cefoxitin and Staphylococcal-Infections

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes severe morbidity and mortality worldwide. For the establishment of national strategies to combat MRSA infection in each country, accurate and current statistics characterizing the epidemiology of MRSA are essential. The purpose of this study was to determine the prevalence of MRSA among Staphylococcus aureus clinical isolates in Egypt. In addition, we aimed to compare different diagnostic methods for MRSA and determine the pooled resistance rate of linezolid and vancomycin to MRSA. To address this knowledge gap, we conducted a systematic review with meta-analysis.. A comprehensive literature search from inception to October 2022 of the following databases was performed: MEDLINE [PubMed], Scopus, Google Scholar, and Web of Science. The review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Statement. Based on the random effects model, results were reported as proportions with a 95% confidence interval (CI). Analyses of the subgroups were conducted. A sensitivity analysis was conducted to test the robustness of the results.. A total of sixty-four (64) studies were included in the present meta-analysis, with a total sample size of 7171 subjects. The overall prevalence of MRSA was 63% [95% CI: 55-70]. Fifteen (15) studies used both PCR and cefoxitin disc diffusion for MRSA detection, with a pooled prevalence rate of 67% [95% CI: 54-79] and 67% [95% CI: 55-80], respectively. While nine (9) studies used both PCR and Oxacillin disc diffusion for MRSA detection, the pooled prevalences were 60% [95% CI: 45-75] and 64% [95% CI: 43-84], respectively. Furthermore, MRSA appeared to be less resistant to linezolid than vancomycin, with a pooled resistance rate of 5% [95% CI: 2-8] to linezolid and 9% [95% CI: 6-12] to vancomycin, respectively.. Our review highlights Egypt's high MRSA prevalence. The cefoxitin disc diffusion test results were found to be consistent with PCR identification of the mecA gene. A prohibition on antibiotic self-medication and efforts to educate healthcare workers and patients about the proper use of antimicrobials may be required to prevent further increases.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Egypt; Humans; Linezolid; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Penicillin-Binding Proteins; Staphylococcal Infections; Vancomycin

To determine whether prophylactic antibiotic administration using cefoxitin at the time of elective caesarean section significantly reduces infectious morbidity.. A tertiary teaching hospital in a large urban city in South Africa.. Women undergoing elective caesarean section.. A prospective, double-blind randomised placebo-controlled trial.. Four hundred and eighty women undergoing elective caesarean section had cefoxitin or placebo administration after umbilical cord clamping. Postpartum complications including febrile morbidity, wound infection, endometritis, urinary tract infection, pneumonia and transient postpartum fever were recorded, as were the duration of hospital stay and the need for therapeutic antibiotics.. Wound infection was the most common complication occurring in 13.3% and 12.5% of women in the placebo and cefoxitin groups, respectively. Prophylactic antibiotics did not decrease febrile morbidity, wound infection, endometritis, urinary tract infection and pneumonia. Women who received cefoxitin stayed on average a day less in hospital than those who received placebo (6.9 vs 7.8 days, risk difference 0.94 CI 1.57 - 0.31 days). Eleven women (4.6%) in the placebo group and eight (3.4%) in the cefoxitin group had microbiological evidence of wound infection. Staphylococcus aureus was the most common pathogen (43%) isolated. Similar proportions in both groups (6.3% placebo and 5.1% cefoxitin) required a course of therapeutic antibiotics.. Antibiotic prophylaxis with cefoxitin in elective caesarean section did not reduce post-operative infectious morbidity in this double-blind randomised placebo controlled trial.

Topics: Adult; Antibiotic Prophylaxis; Cefoxitin; Cephamycins; Cesarean Section; Double-Blind Method; Female; Humans; Length of Stay; Obstetric Labor Complications; Pregnancy; Prospective Studies; Puerperal Infection; Staphylococcal Infections; Surgical Wound Infection; Treatment Outcome

The authors report three trials of B-lactams and carbapenems for soft tissue infections treated on a surgical service: 1) cefmetazole versus cefoperazone, n = 44; 2) cefotetan versus cefoxitin, n = 24; and 3) meropenem versus imipenem, n = 44. A total of 138 hospitalized patients were enrolled with 112 meeting evaluability criteria. Four hundred twenty-three isolates were cultured (mean, three/patient) of which 67 per cent were aerobes and 33 per cent anaerobes. Cure rates for each trial were: 1) 93 per cent; 2) 92 per cent; 3) 100 per cent. Failures were caused by resistant organisms (Streptococcus group D, Bacteroides fragilis and Pseudomonas) appearing in incompletely drained infection sites. Three patients receiving meropenem had adverse effects (headache, nausea) and one receiving cefoxitin (truncal rash). Operative drainage and debridement remain the critical elements in therapy. Agents with longer half lives allowing twice daily dosing (cefmetazole and cefotetan) were as effective and less expensive than multiple doses of short-acting agents. The extended spectrum carbapenems are most useful for severe infections or resistant organisms.

Topics: Adult; Aged; Bacterial Infections; Carbapenems; Cefmetazole; Cefoperazone; Cefotetan; Cefoxitin; Cephalosporins; Drug Combinations; Drug Resistance, Microbial; Escherichia coli Infections; Female; Humans; Imipenem; Male; Meropenem; Middle Aged; Prospective Studies; Remission Induction; Skin Diseases, Infectious; Staphylococcal Infections; Streptococcal Infections; Thienamycins

During a 24-month period, 350 patients were prospectively studied in an effort to determine the perioperative factors in the development of infections after colon and rectal resections. All patients received standard mechanical bowel preparation; perioperative parenteral cefoxitin (group A) or preoperative oral neomycin and erythromycin, in addition to perioperative cefoxitin (Group B), were also given. Both groups were comparable with respect to age, sex, associated diseases, and primary diagnosis. Wound infections developed in nine of 169 (5%) group B patients and in 15 of 141 (11%) group A patients. Stratification by type of operative procedure revealed that the rectal resections involved the highest rate of infection in group A (22%) and in group B (11%). In patients requiring intraperitoneal colon resection, the rates of wound sepsis were similar (3% in both groups). Analysis of length of operation revealed that in operations lasting 215 minutes or more the infection rate was 12%; in those lasting less than 215 minutes the rate was 4%. Patients with rectal resection and operative times of 215 minutes or more had a wound infection rate of 19% compared to 2% (p less than 0.05) in those with shorter nonrectal operations. Group B patients with the longer rectal operations had lower infection rates (11%) than group A patients (27%), while there was no difference among those who had shorter operations. Intra-abdominal abscesses (p less than 0.01) and anastomotic dehiscence (p less than 0.05) were also significantly reduced in group B patients. Postoperative wound infection is associated with length of operation and location of colon resection and can be significantly lowered by a combination of oral and parenteral antibiotics.

Topics: Adult; Aged; Anti-Bacterial Agents; Cefoxitin; Colonic Diseases; Colonic Neoplasms; Escherichia coli Infections; Female; Humans; Male; Middle Aged; Prospective Studies; Random Allocation; Rectal Diseases; Rectal Neoplasms; Staphylococcal Infections; Surgical Wound Infection

Of 152 patients who were scheduled for an amputation for ischemia, seventy-seven were randomly assigned to perioperative prophylaxis with cefoxitin (Mefoxin) and seventy-five patients, to injections of a placebo. The patients were followed for twenty-one days or, in the case of wound complications, to the end of treatment. An infected wound occurred in 38.7 per cent of the patients in the placebo group and 16.9 per cent of those in the antibiotic group (p less than 0.005). Clostridial infection occurred in eight patients in the placebo group and in none in the antibiotic group (p = 0.003). Three of the patients with clostridial infection died of gas gangrene. A multivariate analysis showed that the absence of antibiotic prophylaxis increased the risk of infection by a factor of 3.3 (p = 0.004) and increased the need for reamputation by a factor of 4.5 (p = 0.003). We concluded that amputation patients should have prophylaxis with a broad-spectrum antibiotic given perioperatively.

Topics: Adult; Aged; Amputation, Surgical; Arteriosclerosis; Cefoxitin; Clinical Trials as Topic; Female; Gas Gangrene; Humans; Leg; Male; Middle Aged; Premedication; Random Allocation; Risk; Staphylococcal Infections; Surgical Wound Infection; Time Factors

This prospective study was designed to compare the relative efficacy of two antibiotic regimens for the treatment of operative site infections subsequent to pelvic operations. Patients with endomyoparametritis after delivery or pelvic cellulitis subsequent to hysterectomy were randomized to treatment with the combination of penicillin-gentamicin or the single agent cefoxitin. Seventeen of the 26 patients (65%) with endomyoparametritis who were treated with penicillin-gentamicin were cured by antibiotic therapy alone, in comparison to 15 of 23 (65%) patients treated with cefoxitin. Fifty-eight percent of the patients with pelvic cellulitis who were treated with penicillin-gentamicin responded favorably, in comparison to 50% of the patients treated with cefoxitin. None of these differences was statistically significant. In this study, neither antibiotic regimen provided satisfactory initial treatment for surgically induced soft tissue pelvic infection. Moreover, 11 of the 28 patients with treatment failures (40%) developed serious sequelae of their primary infection.

Topics: Bacterial Infections; Cefoxitin; Cesarean Section; Clindamycin; Clinical Trials as Topic; Delivery, Obstetric; Drug Therapy, Combination; Endometritis; Female; Gentamicins; Humans; Hysterectomy; Infant, Newborn; Parametritis; Penicillins; Peptococcus; Postoperative Complications; Pregnancy; Prospective Studies; Puerperal Infection; Staphylococcal Infections; Streptococcus agalactiae

Topics: Adolescent; Adult; Cefoxitin; Cephalosporins; Clinical Trials as Topic; Female; Humans; Male; Middle Aged; Osteomyelitis; Staphylococcal Infections; Time Factors

Recent evidence has shown that oral antibiotic therapy is not inferior to IV antibiotic therapy in the treatment of complicated Staphylococcus aureus infections. Therefore, oral antibiotic therapy is now frequently prescribed in clinical practice due to cost benefit, ease of administration, decreased complication rate, and lack of need for IV access. In vitro susceptibility testing for β-lactam oral antibiotics is not routinely performed as the guidelines provided by the Clinical and Laboratory Standards Institute (CLSI) recommend using oxacillin and cefoxitin as surrogate markers. Hence, oral antibiotic susceptibilities for cephalexin and dicloxacillin are not reported and implied based on oxacillin and cefoxitin. The objective of the current study was to determine whether susceptibilities among S. aureus isolates are predictable when comparing commonly used IV and oral beta-lactams.. Cefazolin, cephalexin, dicloxacillin, and oxacillin broth microdilution minimum inhibitory concentrations (MICs) were determined for 100 clinical isolates of methicillin-sensitive S. aureus by broth microdilution following CLSI guidelines.. Among these isolates, median MICs for cephalexin were eight-fold higher than cefazolin MICs and median MICs for dicloxacillin were four-fold less than oxacillin MICs. Ten percent of more strains studied had a major or very major error in its susceptibility reporting when cephalexin was compared to its surrogate marker oxacillin.. The variations in MICs observed compounded with the dosing and pharmacokinetic differences of oral versus IV β-lactam suggests that establishing breakpoints for oral β-lactam antibiotics is necessary to ensure adequate therapy is selected for the treatment of complex S. aureus infections.

Topics: Anti-Bacterial Agents; beta-Lactams; Cefazolin; Cefoxitin; Cephalexin; Dicloxacillin; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Monobactams; Oxacillin; Staphylococcal Infections; Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a foodborne bacterial pathogens that can cause staphylococcal food poisoning and contaminate food of animal origin worldwide. The current study was conducted to estimate the prevalence and assess risk factors, hygienic quality, and antibiogram of S. aureus in raw milk and milk products of cows in Ambo and Bako towns, Ethiopia.. Higher prevalence of S. aureus and MDR isolates in milk and milk products was detected in study areas. Therefore, to make milk and milk products safe for human consumption, hygienic handling of milk and milk products, regular surveillance of antimicrobial resistance, and prudent use of drugs are recommended.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cefoxitin; Child, Preschool; Cities; Ethiopia; Female; Humans; Hygiene; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Milk; Oxacillin; Prevalence; Risk Factors; Staphylococcal Infections; Staphylococcus aureus

The presence of Staphylococcus spp. resistant to methicillin in the nasal cavity of swine has been previously reported. Considering the possible occurrence of bacterial resistance and presence of resistance genes in intensive swine breeding and the known transmissibility and dispersion potential of such genes, this study aimed to investigate the prevalence of resistance to different antibiotics and the presence of the mecA resistance gene in Staphylococcus spp. from piglets recently housed in a nursery. For this, 60 nasal swabs were collected from piglets at the time of their housing in the nursery, and then Staphylococcus spp. were isolated and identified in coagulase-positive (CoPS) and coagulase-negative (CoNS) isolates. These isolates were subjected to the disk-diffusion test to evaluate the bacterial resistance profile and then subjected to molecular identification of Staphylococcus aureus and analyses of the mecA gene through polymerase chain reaction. Of the 60 samples collected, 60 Staphylococcus spp. were isolated, of which 38 (63.33%) were classified as CoNS and 22 (36.67%) as CoPS. Of these, ten (45.45%) were identified as Staphylococcus aureus. The resistance profile of these isolates showed high resistance to different antibiotics, with 100% of the isolates resistant to chloramphenicol, clindamycin, and erythromycin, 98.33% resistant to doxycycline, 95% resistant to oxacillin, and 85% resistant to cefoxitin. Regarding the mecA gene, 27 (45%) samples were positive for the presence of this gene, and three (11.11%) were phenotypically sensitive to oxacillin and cefoxitin. This finding highlights the importance of researching the phenotypic profile of resistance to different antimicrobials and resistance genes in the different phases of pig rearing to identify the real risk of these isolates from a One Health perspective. The present study revealed the presence of samples resistant to different antibiotics in recently weaned production animal that had not been markedly exposed to antimicrobials as growth promoters or even as prophylactics. This information highlights the need for more research on the possible sharing of bacteria between sows and piglets, the environmental pressure within production environments, and the exposure of handlers during their transport, especially considering the community, hospital, and political importance of the presence of circulating resistant strains.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Coagulase; Female; Microbial Sensitivity Tests; Nasal Cavity; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Swine; Swine Diseases

The present study is aimed at surveying the antibiotics resistance profile, biofilm formation ability, staphylococcal cassette chromosome. In total, 43. Among all coagulase-negative staphylococci isolates, the highest resistance rate (81.5%) was seen for cefoxitin and cotrimoxazole. All of the isolates were susceptible to linezolid. Out of the 66. The high rate of resistance to antibiotics as well as the possibility of cross-infection shows the importance of a pattern shift in the management and controlling programs of coagulase-negative staphylococci, especially in healthcare centers.

Topics: Anti-Bacterial Agents; Cefoxitin; Coagulase; Health Personnel; Humans; Iran; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis; Staphylococcus haemolyticus

The present study compared multiplex PCR (mPCR) and Whole Genome Sequencing (WGS) using the SCCmecFinder database to identify the Staphylococcal Cassette Chromosome (SCC) mec in five Staphylococcus aureus (SA) and nine non-aureus staphylococci (NAS) isolated from dairy cattle. mPCR identified an SCCmecIV in four SA and one NAS, but could not differentiate between SCCmecII and IV in the fifth SA, that all harbored the mecA gene and were phenotypically resistant to cefoxitin. SCCmecFinder confirmed the presence of an SCCmecIVc(2B) in four SA and of the SCCmecIVa(2B) in the fifth SA and the one NAS. Both methods also detected one untypeable SCCmec in another cefoxitin-resistant NAS harboring the mecA gene and a pseudo SCCmec in one cefoxitin-sensitive NAS harboring one mecC-related gene. No SCCmec elements were identified either in one cefoxitin-sensitive NAS harboring the mecA2 gene, or in five NAS (one resistant and four sensitive to cefoxitin) harboring the mecA1 gene. SCCmecFinder could even not identify the presence of any mecA1 gene in these five NAS, whose presence was nevertheless confirmed by ResFinder. The conclusions of this study are: (i) mPCR and WGS sequencing using SCCmecFinder are complementary methodologies to identify SCCmec; (ii) SCCmecFinder and ResFinder to a lesser extent cannot identify all mec gene allotypes; (iii) a specific classification of the SCCmec in NAS would be epidemiologically helpful; (iv) presence of a mecA gene and a complete SCCmec is linked to cefoxitin resistance, whereas presence of other mec genes and of pseudo or no SCCmec is not.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Belgium; Cattle; Cattle Diseases; Cefoxitin; Chromosomes; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Multiplex Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Whole Genome Sequencing

Therapies which target quorum sensing (QS) systems that regulate virulence in methicillin-resistant Staphylococcus aureus (MRSA) are a promising alternative to antibiotics. QS systems play a crucial in the regulation of MRSA antibiotic resistance, exotoxin production, antioxidant protection and immune cell evasion, and are therefore attractive therapeutic targets to reduce the virulence of a pathogen. In the present work the the effects of bioactive peptides isolated from two strains of lactic acid bacteria were tested against antibiotic resistance, carotenoid production, resistance to oxidative killing and biofilm structure in two clinical MRSA isolates. The results obtained from fractional-inhibitory concentration assays with bulk and semi-purified bioactive molecules showed a significant synergistic effect increasing cefoxitin mediated killing of MRSA. This was coupled to a six-fold decrease of the major membrane pigment staphyloxanthin, and a 99% increase in susceptibility to oxidative stress mediated killing. Real-time quantitative PCR analysis of the QS-genes agrA and luxS, showed differential expression between MRSA strains, and a significant downregulation of the hemolysin gene hla. Light microscopy and scanning electron microscopy revealed alteration in biofilm formation and clustering behavior. These results demonstrate that bioactive metabolites may be effectively applied in tandem with beta-lactam antibiotics to sensitize MRSA to cefoxitin. Moreover, these results shown that several key QS-controlled virulence mechanisms are diminished by probiotic metabolites.

Topics: Anti-Bacterial Agents; Biofilms; Cefoxitin; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Probiotics; Quorum Sensing; Staphylococcal Infections; Virulence

Antibiotic resistance in Staphylococci, particularly methicillin resistance is a major public health concern. While this problem has been reported from the clinical settings, its presence in non-clinical settings also needs to be investigated. The role of wildlife in carrying and disseminating the resistant strains has been established in different studies but its role in Pakistani environment has not been explored yet. To evaluate this, we investigated the carriage of antibiotic resistant Staphylococci in wild birds from Islamabad region.. Birds fecal matter were collected during September 2016-August 2017 from eight different environmental settings of Islamabad. Prevalence of Staphylococci, their susceptibility profile against eight classes of antibiotics through disc diffusion method, their SCCmec types, co-resistance of macrolide and cefoxitin through PCR assay and biofilm formation through microtitre plate assay were studied.. Out of 320 birds feces collected, 394 Staphylococci were isolated, where 165 (42%) were resistant to at least one or two classes of antibiotics. High resistance was found against erythromycin (40%) and tetracycline (21%) while cefoxitin resistance was 18% and vancomycin resistance was only in 2%. One hundred and three (26%) isolates exhibited multi-drug resistance (MDR) pattern. mecA gene was detected in 45/70 (64%) cefoxitin resistant isolates. Community acquired methicillin resistant Staphylococci (CA-MRS) were 87% while Hospital acquired methicillin resistant Staphylococci (HA-MRS) were 40%. In the MRS isolates showing co-resistance to macrolides, mefA (69%) and ermC (50%) genes were more prevalent. Strong biofilm formation was observed in 90% of the MRS, of which 48% were methicillin resistant Staphylococcus aureus (MRSA) isolates while 52% were methicillin resistant coagulase negative Staphylococci (MRCoNS).. Occurrence of methicillin resistant strains of Staphylococci in wild birds suggests their role in the carriage and dissemination of resistant strains into the environment. The findings of the study strongly recommend the monitoring of resistant bacteria in wild birds and wildlife.

Topics: Animals; Animals, Wild; Anti-Bacterial Agents; Cefoxitin; Humans; Macrolides; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus

urinary tract infection (UTI) comes second after respiratory infections in most communities and hospital settings, affecting people of all ages. Frequent use of antibiotics to manage UTI has resulted in development of resistance, calling upon policymakers to fast-track and enforce policies that guide the use of antibiotics in the country. This study intended to determine the current antibiotic resistance to uropathogens among patients attending Kericho County Referral Hospital.. three hundred urine samples from eligible participants were cultured and bacteria colonies identified using biochemical tests. Antibiotic sensitivity was done using Kirby Bauer disk diffusion method on Mueller Hinton Agar.

Topics: Anti-Bacterial Agents; Bacteria; Cefoxitin; Ciprofloxacin; Drug Resistance, Microbial; Escherichia coli; Gentamicins; Hospitals; Humans; Kenya; Microbial Sensitivity Tests; Referral and Consultation; Staphylococcal Infections; Urinary Tract Infections

The purpose of this research is to evaluate the resistance profile of uropathogenic staphylococci bacteria in Casablanca, Morocco.. In this retrospective cross-sectional research carried out from January 2017 to December 2020, isolation and identification were carried out according to the usual techniques in medical microbiology. Staphylococcus aureus isolates were confirmed by polymerase chain reaction (PCR) amplification of the nuc gene, and the antibiogram was performed according to the guidelines of the Antibiogram Committee of the French Society of Microbiology (CA-SFM 2021). The susceptibility of uropathogenic staphylococci to vancomycin was determined with broth microdilution following the recommendations of the Clinical and Laboratory Standards Institute. The mecA gene was tested on phenotypically cefoxitin-resistant S. aureus isolates by PCR.. The prevalence of urinary tract infections (UTIs) was 18% (772/4374). UTIs were more common in females (n = 483, 63%) than males (n = 289, 37%). Among the Gram-positive bacteria isolated (198, 25.65%), the prevalence of staphylococci was (130/198, 65.66%). Among staphylococcal species identified, coagulase-negative staphylococci (CoNS) were more prevalent (112/130, 86.15%), and Staphylococcus saprophyticus was the most frequently isolated CoNS (46/112, 41.07%). Additionally, there were several S. aureus strains (18/130, 13.85%). Forty-four percent of S. aureus isolates (n = 8) were resistant to cefoxitin and also harboured the mecA gene. All S. aureus isolates were susceptible to linezolid, cotrimoxazole and vancomycin.. The prevalence and antibacterial resistance patterns of uropathogenic staphylococci in this study, with a high percentage of methicillin resistance, require careful consideration of antimicrobial therapy for staphylococcal UTIs.

Topics: Anti-Bacterial Agents; Cefoxitin; Coagulase; Cross-Sectional Studies; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Morocco; Prevalence; Retrospective Studies; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Vancomycin

Active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) is a component of our neonatal intensive care unit (NICU) infection prevention efforts. Recent atypical trends prompted review of 42 suspected MRSA isolates. Species identification was confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and methicillin resistance was reevaluated by PBP2a lateral flow assay, cefoxitin/oxacillin susceptibility testing,

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Cefoxitin; Genomics; Humans; Infant, Newborn; Intensive Care Units, Neonatal; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus aureus

Here we characterized the distribution and the antibiotic resistance of staphylococci from a Brazilian pork production chain. Samples (n = 1,114) from pig farms, pig lots, and slaughterhouses, located in two Brazilian states (Minas Gerais and Paraná), were subjected to coagulase-positive Staphylococcus enumeration. S. aureus isolates (n = 251) from this collection were further characterized for their resistance to oxacillin, cefoxitin, vancomycin, and tetracycline through phenotypic and molecular assays. Coagulase-positive Staphylococcus counts from pig farms were higher compared with other samples (P < 0.05). Other counts were relatively low but were present in all production stages. S. aureus isolates were commonly resistant to oxacillin and cefoxitin (54 of 73, 74.0%), qualifying them as methicillin-resistant S. aureus, but PCR assays indicated that few harbored the expected antimicrobial resistance genes (femB, mecA, and mecC). Lower frequencies of vancomycin and tetracycline resistance were found (6.8 to 37.0%). PCR sensitivity (34.5 to 86.7%) and specificity (26.6 to 85.0%) for detection of antibiotic resistance genes varied based on the assessed antibiotic. Antibiotic-resistant staphylococci are widely distributed in the Brazilian pork production chain, and methicillin-resistant S. aureus can become a potential health and economic impediment for the Brazilian pork industry.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Brazil; Cefoxitin; Coagulase; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Pork Meat; Red Meat; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Swine; Vancomycin

The oxacillin- and cefoxitin-susceptible

Topics: Abscess; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Female; Genomics; Humans; Lactation; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Mupirocin; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus aureus

The emergence of antimicrobial resistant bacteria in food producing animals is of growing concern to food safety and health. Staphylococci are common inhabitants of skin and mucous membranes in humans and animals. Infections involving antibiotic resistant staphylococci are associated with increased morbidity and mortality, with notable economic consequences. Livestock farms may enable cross-species transfer of antibiotic resistant staphylococci. The aim of the study was to investigate antimicrobial resistance patterns of staphylococci isolated from livestock and farm attendants in Northern Ghana using phenotypic and genotypic methods. Antimicrobial susceptibility testing was performed on staphylococci recovered from livestock and farm attendants and isolates resistant to cefoxitin were investigated using whole genome sequencing.. One hundred and fifty-two staphylococci comprising S. sciuri (80%; n = 121), S. simulans (5%; n = 8), S. epidermidis (4%; n = 6), S. chromogens (3%; n = 4), S. aureus (2%; n = 3), S. haemolyticus (1%; n = 2), S. xylosus (1%; n = 2), S. cohnii (1%; n = 2), S. condimenti (1%; n = 2), S. hominis (1%; n = 1) and S. arlettae (1%; n = 1) were identified. The isolates showed resistance to penicillin (89%; n = 135), clindamycin (67%; n = 102), cefoxitin (19%; n = 29), tetracycline (15%; n = 22) and erythromycin (11%; n = 16) but showed high susceptibility to gentamicin (96%; n = 146), sulphamethoxazole/trimethoprim (98%; n = 149) and rifampicin (99%; n = 151). All staphylococci were susceptible to linezolid and amikacin. Carriage of multiple resistance genes was common among the staphylococcal isolates. Genome sequencing of methicillin (cefoxitin) resistant staphylococci (MRS) isolates revealed majority of S. sciuri (93%, n = 27) carrying mecA1 (which encodes for beta-lactam resistance) and the sal(A) gene, responsible for resistance to lincosamide and streptogramin. Most of the MRS isolates were recovered from livestock.. The study provides insights into the genomic content of MRS from farm attendants and livestock in Ghana and highlights the importance of using whole-genome sequencing to investigate such opportunistic pathogens. The finding of multi-drug resistant staphylococci such as S. sciuri carrying multiple resistant genes is of public health concern as they could pose a challenge for treatment of life-threatening infections that they may cause.

Topics: Animals; Anti-Bacterial Agents; Cefoxitin; Drug Resistance, Bacterial; Farms; Genomics; Ghana; Humans; Livestock; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Staphylococcus epidermidis

The current study was designed to characterize methicillin-resistant Staphylococcus aureus (MRSA) isolated from bovine milk, along with its response to antibiotics, and ultimately reverse its mechanism of resistance by modulation with non-antibiotics. The synergistic combination of antibiotics with NSAIDs were tested in-vivo by giving MRSA challenge to rabbits. The current study reported an overall 23.79% prevalence of MRSA. The BLAST alignment of current study sequences revealed 99% similarity with mecA gene of MRSA from NCBI database. The current study isolates were more similar to each other and also with reference sequences as compared to other mecA gene sequences from Turkey, India, and Russia. Antibiogram of MRSA isolates showed a highly resistant response to cefoxitin, amoxicillin, and gentamicin. Amoxicillin, gentamicin, tylosin, vancomycin, and ciprofloxacin elicited a significant response (p < 0.05) in combination with non-antibiotics against tested MRSA isolates. The highest zone of inhibition (ZOI) increase was noted for vancomycin in combination with flunixin meglumine (145.45%) and meloxicam (139.36%); gentamicin with flunixin meglumine (85.71%) and ciprofloxacin with ivermectin (71.13%). Synergistic behavior was observed in the combination of gentamicin with ketoprofen; sulfamethoxazole and oxytetracycline with meloxicam. Hematological analysis showed significant differences (p < 0.05) among lymphocyte count and bilirubin. On histopathological examination of skin tissue, hyperplasia of epithelium, sloughed off epidermis, hyperkeratosis, infiltration of inflammatory cells, and hemorrhages were observed. The highest cure rate was observed in case of gentamicin in combination with ketoprofen as compared to other treatment groups. The current study concluded antibiotics in combination with non-antibiotics as potential therapeutic agents for resistance modulation against MRSA. This study will help to devise treatment and control strategies against bovine mastitis. Although the prospect of using NSAIDs to manage infections caused by MRSA appears to be a promising direction, further studies should be conducted to test these medications using suitable in-vivo models in controlled clinical trials to justify their repurposing as a treatment for MRSA infections.

Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Bilirubin; Cattle; Cefoxitin; Ciprofloxacin; Drug Repositioning; Female; Gentamicins; Ivermectin; Ketoprofen; Mastitis, Bovine; Meloxicam; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxytetracycline; Rabbits; Staphylococcal Infections; Sulfamethoxazole; Tylosin; Vancomycin

Compared to the clinical sector, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the food sector is relatively low. However, their presence in seafood is a significant public health concern. In India, fish and fishery products are maximally manually handled compared to other food products. In this study, 498 fish samples were collected under various conditions (fresh, chilled or dressed) and representatives from their surroundings. These samples were screened for the prevalence of Staphylococcus aureus, determining its antimicrobial resistance, MRSA and genetic profile. It is observed that 15.0% and 3.0% of the total samples were screened positive for S. aureus and MRSA, respectively. The S. aureus strain MRSARF-10 showed higher resistance to linezolid, co-trimoxazole, cefoxitin, ofloxacin, gentamicin, rifampicin, ampicillin/sulbactam and Piperacillin-tazobactam. This MRSA, spa type t021 and SCCmec type V strain isolated from dried ribbon fish (Family Trachipteridae) carried virulence factors for exoenzymes such as aureolysin, serine, toxin genes and a novel MLST ST 243, as revealed from its draft-genome sequence. This highly pathogenic, multidrug-resistant and virulent S. aureus novel strain is circulating in the environment with chances of spreading among the seafood workers and the environment. It is further suggested that Good Hygienic Practices recommended by World Health Organization need to be followed during the different stages of seafood processing to provide pathogen-free fish and fishery products to the consumers.

Topics: Ampicillin; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Cefoxitin; Gentamicins; Linezolid; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Multilocus Sequence Typing; Ofloxacin; Piperacillin; Prevalence; Rifampin; Seafood; Serine; Staphylococcal Infections; Staphylococcus aureus; Sulbactam; Tazobactam; Trimethoprim, Sulfamethoxazole Drug Combination; Virulence Factors

The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in pets and their owners has increased due to the misuse and abuse of antibiotics. This study compared the prevalence of MRSA and Staphylococcus aureus strains in pets and their owners in urban and rural communities in Trinidad.. Questionnaires were administered to gather demographic and risk factor data for MRSA for human participants, and their pets. Nasal swabs were obtained from 100 pets (dogs and cats) and their human owners. For the isolation of MRSA, nasal swabs obtained were enriched and then plated on selective media. Staphylococcus aureus was identified using standard biochemical procedures. The resistance of S. aureus initially assessed detection of MRSA isolates to cefoxitin and confirmed by the PBP2a latex agglutination test. Antibiotic resistance was determined using the disc diffusion method.. The prevalence of MRSA was 6.0% (3/50) and 2.0% (1/50) in household pet animals and their owners, respectively in urban communities, while in rural communities, the prevalence was 6.0% (3/50) and 12.0% (6/50) respectively. The prevalence of S. aureus in pet owners was higher in the rural community (44.0%) compared to urban (30.0%). However, in pet animals, S. aureus was more frequently isolated from urban communities (78.0%) than rural ones (66.0%). Amongst the S. aureus isolates, 81.7% were resistant to one or more antimicrobial agents.. This study has demonstrated that living in a rural community increased the odds of MRSA colonization.

Topics: Animals; Anti-Bacterial Agents; Cat Diseases; Cats; Cefoxitin; Dog Diseases; Dogs; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Pets; Rural Population; Staphylococcal Infections; Staphylococcus aureus; Trinidad and Tobago

Pediatric sepsis due to Staphylococcus aureus (S. aureus) is associated with high morbidity and mortality. Accessory-Gene-Regulator (agr) has a role in the pathogenesis of S. aureus through controlling and regulating the expression of virulence genes. Therefore, the aim of the present study was to investigate the prevalence of genotypes of the agr system in S. aureus isolated from children with sepsis and to assess their relationship to biofilm formation and antibiotic resistance.. The study was a retrograde cross-sectional study that included 131 children with health care associated sepsis due to S. aureus. The isolated S. aureus was investigated for their ability to form biofilm by microplate method, antibiotic susceptibility pattern by disc diffusion method, and molecular determination of agr genotypes by polymerase chain reaction (PCR).. Methicillin resistant S. aureus (MRSA) was defined by resistance to cefoxitin antibiotic disc in 70 (53.4%) of the isolates and biofilm formation was positive in 67 (58%) of the isolates. Molecular study of the agr genes revealed that 54 (41.2%), 40 (30.5%), 27 (20.6%), and 10 (7.5%) of the studied isolates had agr I, agr II, agr III, and agr IV, respectively. In comparison between MRSA and methicillin sensitive S. aureus (MSSA), there was a signif-icant increase in biofilm formation among MRSA (65.7%, p = 0.01) compared to MSSA (34.3%) and an increase in agr genotype I among MRSA (68.6%, p = 0.001) compared to agr I in MSSA (9.8%). There was a significant association with the presence of a central venous catheter (51.4%, p = 0.001) and urinary tract catheter (81.4%, p = 0.001) in children with MRSA compared to children with MSSA (21.3%, OR = 3.9, 95% CI = 1.8 - 8.5 and 36.1%, OR = 7.8, 95% CI 3.5 - 17.3, respectively).. There was an increase in the biofilm formation among S. aureus isolated from pediatric patients with sepsis with a significant increase in MRSA. The agr group I was the main agr gene among the isolated S. aureus. Moreover, agr I was the predominant gene in MRSA isolates and was significantly associated with biofilm formation.

Topics: Anti-Bacterial Agents; Cefoxitin; Child; Cross-Sectional Studies; Humans; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Sepsis; Staphylococcal Infections; Staphylococcus aureus

In order to restrict the spread of methicillin-resistant

Topics: Aminoglycosides; Anti-Bacterial Agents; Cefoxitin; Clindamycin; Erythromycin; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Staphylococcal Infections; Virulence Factors

Topics: Adult; Blood Culture; Cefoxitin; Humans; Methicillin; Staphylococcal Infections; Staphylococcus aureus

Staphylococcus lugdunensis is a Gram-positive coagulase-negative bacterium and is recognized as a critical pathogenic species recently. Here, we aimed to evaluate the cefoxitin disk diffusion (CDD), oxacillin agar dilution (OAD), and mecA PCR for detecting oxacillin-resistant S. lugdunensis (ORSL) isolates.. Multilocus sequence typing (MLST) analysis was performed to determine the clonality of 117 S. lugdunensis isolates isolated between May 2009 and Jul 2014. CDD, OAD, and mecA PCR were used to identify oxacillin-resistant S. lugdunensis (ORSL).. MLST results showed that the most common sequence type (ST) of our S. lugdunensis isolates was ST6 (35.9%) followed by ST3 (28.2%), ST27 (17.9%), and ST4 (6.8%). CDD and OAD showed that 39 and 43 isolates were ORSL, respectively. 4 ST3 CDD-susceptible S. lugdunensis (OSSL) isolates had MIC values ≥ 4 for oxacillin. mecA PCR results showed that 43 OAD-resistant S. lugdunensis and 3 OAD-susceptible ST27 S. lugdunensis had the mecA gene. Therefore, OAD was used as the gold standard to evaluate the performance of CDD and mecA PCR for identifying ORSL. The overall sensitivity, specificity, and accuracy of CCD for ORSL detection was 90.7%, 100%, and 96.8%, respectively. The sensitivity, specificity, and accuracy of mecA PCR for identifying ORSL was 100%, 95.9%, and 97.44%, respectively.. Our results indicate that OAD shows higher accuracy for ORSL detection compared with CDD and mecA PCR.

Topics: Agar; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Drug Resistance, Bacterial; Humans; Microbial Sensitivity Tests; Multilocus Sequence Typing; Oxacillin; Staphylococcal Infections; Staphylococcus lugdunensis

Oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA) represents an important issue, as its oxacillin susceptibility has contributed to misidentification by conventional susceptibility tests and consequently potential therapeutic failure, but limited data on the current status of OS-MRSA infection in Chinese hospitals are available.. This multicenter study performed a battery of susceptibility tests and diagnostic tests for 956 S. aureus isolates from 10 hospitals, including automated susceptibility testing on VITEK 2, broth microdilution, disk diffusion, and detection of PBB2a, mecA gene and mecC gene. For all identified OS-MRSA, multi-locus sequence typing (MLST), together with spa typing, SCCmec typing and PVL detecting, was carried out.. OS-MRSA, most of which were from pediatric inpatients, represented 1.8% (17/956) of total isolates. Of these 17 OS-MRSA, 10 were ST59, followed by ST965 (3/17), and 11 carried SCCmec type IV, while 5 carried SCCmec type V, but only one was Panton-Valentine leucocidin (PVL)-positive, also, 16 had one or two point mutations within mecA promoter. OS-MRSA had inducible oxacillin resistance and significantly lower MDR (Multi-Drug Resistant) rate. We observed that the VITEK 2 system exhibited some deficiency in OS-MRSA detection, whereas cefoxitin disk diffusion was shown to be a reliable and cost-saving alternative and should be supplemented in detecting S. aureus with borderline oxacillin susceptible MICs.. This study has characterized phenotypically and molecularly OS-MRSA in China, and provided insights into more effective management of OS-MRSA.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Child; China; Cities; Drug Resistance, Multiple, Bacterial; Genotype; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Multilocus Sequence Typing; Mutation; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections

This study was designed to determine antimicrobial resistance phenotypes and genotypes and virulence factors in Staphylococcus aureus and coagulase-negative staphylococci (CNS) in unpasteurized milk sold in Djelfa, Algeria. Eighty-two unpasteurized cow milk samples were randomly obtained from 82 retail stores in Djelfa and tested to detect staphylococci. Species were identified by biochemical tests and MALDI-TOF. Antimicrobial resistance phenotypes and genotypes were determined by disk diffusion test, PCR, and sequencing. The Staph. aureus isolates were subjected to spa typing, multilocus sequence typing, and detection of virulence genes and the scn gene by PCR and sequencing. Forty-five (54.9%) milk samples were contaminated by staphylococci and 45 isolates were recovered: 10 Staph. aureus (12.2% of total samples) and 35 CNS (42.7%). Resistance to penicillin (blaZ), tetracycline (tetL/tetK), and erythromycin (ermB/msrA/ermC) were the most common phenotypes (genotypes). Three CNS were methicillin-resistant and all were mecA-positive. The Staph. aureus isolates were ascribed to the following lineages [spa type/sequence type/associated clonal complex (number of isolates)]: t267/ST479/CC479 (n = 6), t1510/ST5651/CC45 (n = 1), t359/ST97/CC97/ (n = 1), t346/ST15/CC15 (n = 1), and t044/ST80 (n = 1). The mecA gene was detected in the cefoxitin-susceptible t044/ST80 isolate and co-harbored the lukF/lukS-PV and scn genes. The detection of mecA-PVL-positive Staph. aureus, methicillin-resistant CNS, and multidrug-resistant staphylococcal species indicates a potentially serious health issue and reveals that unpasteurized milk sold in Djelfa city could be a potential vehicle for pathogenic and antimicrobial-resistant staphylococci.

Topics: Algeria; Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Cefoxitin; Coagulase; Female; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Milk; Staphylococcal Infections; Staphylococcus aureus

A major determinant of β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is the drug insensitive transpeptidase, PBP2a, encoded by mecA. Full expression of the resistance phenotype requires auxiliary factors. Two such factors, auxiliary factor A (auxA, SAUSA300_0980) and B (auxB, SAUSA300_1003), were identified in a screen against mutants with increased susceptibility to β-lactams in the MRSA strain, JE2. auxA and auxB encode transmembrane proteins, with AuxA predicted to be a transporter. Inactivation of auxA or auxB enhanced β-lactam susceptibility in community-, hospital- and livestock-associated MRSA strains without affecting PBP2a expression, peptidoglycan cross-linking or wall teichoic acid synthesis. Both mutants displayed increased susceptibility to inhibitors of lipoteichoic acid (LTA) synthesis and alanylation pathways and released LTA even in the absence of β-lactams. The β-lactam susceptibility of the aux mutants was suppressed by mutations inactivating gdpP, which was previously found to allow growth of mutants lacking the lipoteichoic synthase enzyme, LtaS. Using the Galleria mellonella infection model, enhanced survival of larvae inoculated with either auxA or auxB mutants was observed compared with the wild-type strain following treatment with amoxicillin. These results indicate that AuxA and AuxB are central for LTA stability and potential inhibitors can be tools to re-sensitize MRSA strains to β-lactams and combat MRSA infections.

Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Bacterial Proteins; beta-Lactam Resistance; beta-Lactams; Cefoxitin; Cell Wall; DNA, Bacterial; Drug Resistance, Bacterial; Humans; Larva; Lipopolysaccharides; Membrane Proteins; Meropenem; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Models, Animal; Moths; Mutation; Octoxynol; Oxacillin; Penicillin-Binding Proteins; Peptidoglycan; Phenotype; Staphylococcal Infections; Teichoic Acids; Virulence

Methicillin resistant Staphylococcus aureus (MRSA) constitute a serious health care problem worldwide. This study addresses the effect of β-lactam treatment on the ability of clinically relevant MRSA strains to induce IL-12 and IL-23. MRSA strains induced a dose-dependent IL-12 response in murine bone-marrow-derived dendritic cells that was dependent on endocytosis and acidic degradation. Facilitated induction of IL-12 (but not of IL-23) called for activation of the MAP kinase JNK, and was suppressed by p38. Compromised peptidoglycan structure in cefoxitin-treated bacteria - as denoted by increased sensitivity to mutanolysin -caused a shift from IL-12 towards IL-23. Moreover, cefoxitin treatment of MRSA led to a p38 MAPK-dependent early up-regulation of Dual Specificity Phosphatase (DUSP)-1. Compared to common MRSA, characteristics associated with a persister phenotype increased intracellular survival and upon cefoxitin treatment, the peptidoglycan was not equally compromised and the cytokine induction still required phagosomal acidification. Together, these data demonstrate that β-lactam treatment changes the MRSA-induced IL-12/IL-23 pattern determined by the activation of JNK and p38. We suggest that accelerated endosomal degradation of the peptidoglycan in cefoxitin-treated MRSA leads to an early expression of DUSP-1 and accordingly, a reduction in the IL-12/IL-23 ratio in dendritic cells. This may influence the clearance of S. aureus.

Topics: Animals; Anti-Bacterial Agents; Bone Marrow Cells; Cefoxitin; Dendritic Cells; Interleukin-12; Interleukin-23; Methicillin-Resistant Staphylococcus aureus; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Signal Transduction; Staphylococcal Infections

This study evaluated disc diffusion tests and agar screening for detecting mecA-mediated oxacillin resistance in Staphylococcus lugdunensis (S. lugdunensis).. Staphylococcus lugdunensis isolates (n = 179) from diverse sources in Hong Kong during 1998-2018 were investigated by disc diffusion tests (cefoxitin and oxacillin) and inoculation onto oxacillin (1 μg/mL and 2 μg/mL) and chromID methicillin-resistant Staphylococcus aureus (MRSA) agars. The results were compared with mecA PCR as the reference. Isolates with discordant results were further tested by MIC and penicillin-binding protein 2a (PBP2a) assays.. Cefoxitin and oxacillin zone diameters were not distributed in ways that allowed reliable division of the mecA-positive (n = 52) and mecA-negative (n = 127) isolates. On applying the 2019 Clinical Laboratory Standards Institute (CLSI) M100 breakpoints for cefoxitin disc results, there was 88% categorical agreement (CA) and 40% very major error (VME). Screening using 2 μg/mL oxacillin agar reliably differentiated mecA-positive and mecA-negative isolates (100% CA) without any major error (ME) or VME results. The performance of screening using 1 μg/mL oxacillin agar or ChromID MRSA agar was variable (74-89% CA, 0-38% ME and 0-37% VME). The mecA-positive isolates (n = 21) that could not be detected by the cefoxitin disc test were further characterised. The cefoxitin MIC for all 21 isolates was ≤4 μg/mL. Twenty isolates had an oxacillin MIC of 1-2 μg/mL and one had an oxacillin MIC of 4 μg/mL. All had positive PBP2a results and were typed as clonal cluster 27/SCCmec V.. These findings highlight the need to evaluate phenotypic methods using mecA-positive S. lugdunensis with different oxacillin resistance phenotypes.

Topics: Agar; Bacterial Load; Bacterial Proteins; Carrier State; Cefoxitin; Disk Diffusion Antimicrobial Tests; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Phenotype; Staphylococcal Infections; Staphylococcus lugdunensis

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus aureus

To determine methicillin resistance in staphylococcus aureus by different phenotypic methods, and to evaluate their accuracy with mecA gene polymerase chain reaction for methicillin-resistant staphylococcus aureus detection.. The descriptive cross-sectional study was conducted from January to December 2015 at the Post- Graduate Medical Institute, Lahore, Pakistan, and comprised consecutive, non-repetitive clinical isolates of methicillin-resistant staphylococcus aureus that were screened with oxacillin disk 1μg and cefoxitin disk 30μg by Kirby-Bauer method using Clinical and Laboratory Standards Institute guideline. The isolates were cultured on oxacillin screen and mannitol salt agar, and subjected to latex agglutination for penicillin-binding protein 2aand polymerase chain reaction for mecA gene. Data was analysed using SPSS 20.. All the 105 isolates were resistant on oxacillin and cefoxitin disk diffusion test, but 95(90.47%) were positive for mecA gene by latex agglutination and polymerase chain reaction. The sensitivity of oxacillin salt agar, mannitol salt agar and latex agglutination was 94.31%, 96.73% and 98.95%, respectively. Keeping polymerase chain reaction as the gold standard, the specificity and diagnostic accuracy of latex agglutination were 77.77% and 97.14% respectively, which was the highest among all the phenotypic methods.. Latex agglutination method can be proposed as a swiftly reliable diagnostic technique for the detection of mecA gene in methicillin-resistant staphylococcus aureus isolates in resource-constrained settings where molecular methods are limited.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Disk Diffusion Antimicrobial Tests; Humans; Latex Fixation Tests; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Oxacillin; Penicillin-Binding Proteins; Phenotype; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections

Methicillin resistant Staphylococcus aureus (MRSA) causes illness to people and can be picked up from both healthcare facilities and the environment leading to high morbidity and mortality. The study was aimed at identifying phenotypic characteristics of Methicillin-Resistant Staphylococcus aureus and determine the antibiotic susceptibility pattern of clinical samples isolated from patients attending or admitted in two health facilities in Kiambu County, Kenya.. One hundred and thirty-eight (138) clinical samples were collected from patients attending Thika and Kiambu Level-5 Hospitals. The isolates were obtained using standard bacteriological techniques. Methicillin resistance of Staphylococcus aureus was determined using the cefoxitin disk diffusion test.. Out of 138 samples, 54 (39.1%) were found to have Staphylococcus aureus of which 22 (40.7%) were shown to be MRSA using the cefoxitin- based susceptibility test. Antibiotic susceptibility testing using Kirby-Bauer technique was performed on all 54 isolates. The highest sensitivity was found in chloramphenicol 46 (85.2%) and lowest in penicillin-G 8 (14.8%). Multi-Drug Resistance (MDR) was reported in 35 (64.8%) of the 54 isolates of Staphylococcus aureus. All 22 MRSA strains were found to be MDR.. the data obtained revealed that there is presence of MRSA in healthcare settings in Kiambu County, Kenya with varying antibiotic sensitivity patterns as well as multidrug resistance. The findings will help healthcare workers in the county to develop preventive strategy as well as institute policy for antibiotic usage, infection control and surveillance.

Topics: Adolescent; Adult; Aged; Anti-Bacterial Agents; Cefoxitin; Child; Child, Preschool; Cross-Sectional Studies; Drug Resistance, Multiple, Bacterial; Female; Humans; Infant; Kenya; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Phenotype; Qualitative Research; Staphylococcal Infections; Young Adult

Until recently, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommended the cefoxitin disc to screen for mecA-mediated β-lactam resistance in Staphylococcus pseudintermedius. A recent study indicated that cefoxitin was inferior to oxacillin in this respect. We have re-evaluated cefoxitin and oxacillin discs for screening for methicillin resistance in S. pseudintermedius.. We included 224 animal and human S. pseudintermedius isolates from Europe (n = 108) and North America (n = 116), of which 109 were mecA-positive. Disc diffusion was performed per EUCAST recommendations using 30-μg cefoxitin and 1-μg oxacillin discs from three manufacturers and Mueller-Hinton agar from two manufacturers.. Cefoxitin inhibition zones ranged from 6 to 33 mm for mecA-positive S. pseudintermedius (MRSP) and from 29 to 41 mm for mecA-negative S. pseudintermedius (MSSP). The corresponding oxacillin zone intervals were 6-20 mm and 19-30 mm. For cefoxitin 16% (95% CI 14.8-18.0%) of the isolates were in the area where positive and negative results overlapped. For oxacillin the corresponding number was 2% (1.6-2.9%). For oxacillin a breakpoint of susceptible (S) ≥ 20 mm and resistant (R) <20 mm resulted in only 0.4% and 1.1% very major error and major error rates respectively.. This investigation confirms that the 1-μg oxacillin disc predicts mecA-mediated methicillin resistance in S. pseudintermedius better than the 30-μg cefoxitin disc. For a 1-μg oxacillin disc we propose that 20 mm should be used as cut off for resistance, i.e. isolates with a zone diameter <20 mm are resistant to all β-lactam antibiotics except those with activity against methicillin-resistant staphylococci.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; beta-Lactam Resistance; Cefoxitin; Disk Diffusion Antimicrobial Tests; Humans; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus

Introduction: Infections associated with health care caused by S. aureus and coagulase-negative Staphylococci multi-resistant to antibiotics cause a high epidemiological impact due to their high morbidity and mortality. Biofilm formation, which has been associated with antimicrobial resistance, can also occur.\ Objectives: To determine methicillin resistance and to quantify the biofilm production to establish if there is a relationship in clinical isolates of S. aureus and coagulase-negative Staphylococci.\ Material and methods: A total of 11 strains of S. aureus and 12 of coagulase-negative Staphylococci were studied. Methicillin resistance was determined with cefoxitin discs and the Clinical Laboratory Standards Institute (CSLI), 2018 reference values. Biofilm production was quantified by the crystal violet method. The mecA and icaADBC genes were identified by PCR. A bivariate analysis was performed with chi-square (c2) and Cramér’s V statistical tests, using SPSS™, version 20.0 software.\ Results: Nine S. aureus strains were methicillin-resistant and two were sensitive. Eight coagulase-negative Staphylococci strains were resistant and four were sensitive. The mecA genotype was found in eight of the nine S. aureus resistant strains and six of eight resistant coagulase-negative Staphylococci. All strains formed biofilms. Ten strains of S. aureus and 11 of coagulase-negative Staphylococci presented the icaADCB genotype. No association was found between methicillin-resistance and biofilm formation.\ Conclusions: Cefoxitin is enough to define the resistance phenotype and is associated with the mecA genotype. All strains formed biofilms and were related to the presence of the icaADCB operon. Biofilm formation and methicillin resistance were independent features in both groups of strains.. Introducción. Las infecciones por Staphylococcus aureus y Staphylococcus coagulasa negativa multirresistentes a los antibióticos y asociadas con la atención en salud tienen un gran impacto epidemiológico por su alta morbimortalidad; además, se han relacionado con la formación de biopelículas, lo cual también se asocia con la resistencia a los antimicrobianos. Objetivo. Determinar la resistencia a la meticilina y cuantificar la producción de biopelículas para establecer su posible relación con los aislamientos clínicos de S. aureus y Staphylococcus coagulasa negativa. Materiales y métodos. Se estudiaron 11 cepas de S. aureus y 12 de Staphylococcus coagulasa negativa. La resistencia a la meticilina se determinó con discos de cefoxitina tomando como valores de referencia los estándares del Clinical Laboratory Standards Institute (CLSI) de 2018. La producción de biopelícula se cuantificó con cristal violeta. Los genes mecA e icaADBC se identificaron mediante reacción en cadena de la polimerasa (PCR), y se hizo un análisis bivariado con la prueba de ji al cuadrado y el coeficiente V de Cramér, utilizando el programa SPSS™, versión 20.0. Resultados. Nueve cepas de S. aureus fueron resistentes a la meticilina (SARM) y dos fueron sensibles. Ocho cepas de Staphylococcus coagulasa negativa fueron resistentes y cuatro fueron sensibles. El genotipo mecA se encontró en ocho de las nueve cepas de S. aureus y en seis de las ocho de Staphylococcus coagulasa negativa resistentes a meticilina. Todas las cepas formaron biopelícula. Diez cepas de S. aureus y 11 de Staphylococcus coagulasa negativa presentaron el genotipo icaADCB. No se encontró asociación entre la resistencia a meticilina y la formación de biopelícula. Conclusiones. La cefoxitina es suficiente para determinar el fenotipo resistente a meticilina y se asoció con el genotipo mecA. Las cepas resistentes a la meticilina y poseedoras del gen mecA pueden presentar un mecanismo de resistencia alterno. Los dos grupos de cepas formadoras de biopelícula se relacionaron con la presencia del operón icaADCB. La formación de biopelícula y la resistencia a la meticilina se expresaron como características independientes en los dos grupos de cepas.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Biofilms; Cefoxitin; Coagulase; DNA, Bacterial; Genes, Bacterial; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Mexico; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is a cause of zoonotic infections in many countries. People with occupational contact with food animal production are at risk of colonization. The aim of this study was to determine the prevalence of MRSA and their frequency of resistance to other antimicrobial agents from broilers and workers at the 'pluck shops' in Trinidad. For isolation of MRSA, choanal, cloacal and pharyngeal swabs taken from broilers and nasal swabs from humans were enriched then plated on CHROMagar MRSA and Brilliance MRSA. MRSA was confirmed using the PBP2a test kit, resistance to oxacillin and cefoxitin and polymerase chain reaction (PCR) for the mecA gene. Antimicrobial resistance of the MRSA isolates to 16 antimicrobial agents was determined using the disc diffusion method. Of the 287 broilers and 47 humans sampled, MRSA was isolated at a frequency of 2 (0.7%) and 0 (0.0%) respectively. All the MRSA isolates exhibited resistance to one or more of the 16 antimicrobial agents. The study demonstrated that broilers at 'pluck shops' in Trinidad harbor MRSA. This is the first isolation of MRSA from poultry in Trinidad, West Indies, and this finding is of public health significance since occupational exposure of humans can lead to increased risk of acquiring MRSA infections.

Topics: Animals; Anti-Bacterial Agents; Cefoxitin; Chickens; Cross-Sectional Studies; Drug Resistance, Multiple, Bacterial; Humans; Livestock; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Nasal Mucosa; Occupational Exposure; Oxacillin; Polymerase Chain Reaction; Prevalence; Serogroup; Staphylococcal Infections; Trinidad and Tobago

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Humans; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections

This study evaluated the diagnostic test accuracy of disc diffusion relative to broth-microdilution for clinical Staphylococcus pseudintermedius isolated from dogs in Australia (n = 614). Accuracy of disc diffusion and broth-microdilution for oxacillin relative to mecA real-time PCR was also assessed. Each isolate had paired minimum inhibitory concentration and zone diameter values for ten antimicrobial agents. Data was dichotomised using Clinical and Laboratory Standards Institute susceptible and resistant clinical breakpoints. Test accuracy was reported using relative diagnostic sensitivity (RSe), specificity (RSp), likelihood ratio pairs, diagnostic odds ratio, and area-under-the receiver-operating characteristic (ROC AUC) analysis. Disc diffusion was found to have high test accuracy for most antimicrobials (ROC AUC range: 0.96 - 0.99) except rifampicin (ROC AUC = 0.80). The RSp of disc diffusion was high for all antimicrobials (range, 97.1%-100%). However, RSe was considerably variable (range, 35.7%-98.8%), particularly for amoxicillin-clavulanic acid (51.5%, 95% CI, 38.9%, 64.0%), cefoxitin (35.7%, 95% CI, 12.8%, 64.9%), and cephalothin (43.6%, 95% CI, 27.8%, 60.4%). When disc diffusion and broth-microdilution were compared to mecA real-time PCR, the overall accuracy of both assays was similar (ROC AUC, 0.99 respectively). However, the RSe for broth-microdilution (96.1%, 95% CI, 88.9%, 99.2%) was significantly higher than for disc diffusion (86.8%, 95% CI, 77.1%, 93.5%) (McNemars mid-p value 0.01). Overall, these findings demonstrate that for most antimicrobials, disc diffusion performed according to CLSI guidelines can be used to differentiate clinical S. pseudintermedius isolates that might otherwise be assessed by broth-microdilution, provided consideration is given to the performance estimates reported here.

Topics: Animals; Anti-Bacterial Agents; Cefoxitin; Disk Diffusion Antimicrobial Tests; Dog Diseases; Dogs; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Oxacillin; Phenotype; Reproducibility of Results; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with significant morbidity and mortality and has resultant important economic and societal costs underscoring the need for accurate surveillance. In recent years, prevalence rates reported in East Africa have been inconsistent, sparking controversy and raising concern.. We described antimicrobial susceptibility patterns of Staphylococcus aureus isolates cultured from patients within the Internal Medicine department of the largest public healthcare facility in East and Central Africa- the Kenyatta National Hospital (KNH) in Nairobi, Kenya. Routine antimicrobial susceptibility data from non-duplicate Staphylococcus aureus isolates cultured between the years 2014-2016 from the medical wards in KNH were reviewed.. Antimicrobial susceptibility data from a total of 187 Staphylococcus aureus isolates revealed an overall MRSA prevalence of 53.4%. Isolates remained highly susceptible to linezolid, tigecycline, teicoplanin and vancomycin.. The prevalence of MRSA was found to be much higher than that reported in private tertiary facilities in the same region. Careful interrogation of antimicrobial susceptibility results is important to uproot any red herrings and reserve genuine cause for alarm, as this has a critical bearing on health and economic outcomes for a population.

Topics: Adult; Africa, Eastern; Anti-Bacterial Agents; Cefoxitin; Female; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Prevalence; Staphylococcal Infections; Staphylococcus aureus

Topics: Adult; Aged; Anti-Bacterial Agents; Bacteremia; Bacterial Proteins; Cefoxitin; Female; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Oxacillin; Penicillin-Binding Proteins; Retrospective Studies; Staphylococcal Infections; Treatment Outcome; Vancomycin; Young Adult

The detection of methicillin-resistant Staphylococcus aureus (MRSA) and other emerging strains in meat-producing animals and retail meat has increased the risk of contamination of food. The aim of this study was to determine the prevalence and characterize S. aureus strains isolated from the pork chain supply in Chile. A total of 487 samples were collected: 332 samples from pigs at farms and slaughterhouses (nasal, n = 155; skin, n = 177); 85 samples from carcasses at slaughterhouses; and 70 meat samples at supermarkets and retail stores. The isolation of S. aureus was carried out by selective enrichment and culture media. Biochemical testing (API

Topics: Abattoirs; Animals; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Chile; Drug Resistance, Multiple, Bacterial; Enterotoxins; Food Microbiology; Meat; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Prevalence; Staphylococcal Infections; Staphylococcus aureus; Swine

In vitro trends of cefazolin and ceftriaxone susceptibilities from pediatric clinical isolates of methicillin-susceptible Staphylococcus aureus (MSSA) between 2011 and 2016 were analyzed for surveillance.. Our laboratory continues to use agar disk diffusion for staphylococcal susceptibilities applying Clinical Laboratory Standard Institute's 2012 breakpoints.. A total of 3992 MSSA clinical isolates in the last 6 years were analyzed for their in vitro cefazolin and ceftriaxone susceptibilities. While all MSSA isolates exhibited cefazolin susceptibilities within the "susceptible" zone range, there have been a proportion of isolates with ceftriaxone susceptibilities falling in "intermediate" zones, ranging from 2.6% in 2011 to 8.3% in 2016.. Cefazolin continues to be the recommended agent for MSSA treatment at our institution, reflected by the finding that only 2% (6/321) of patients who received ceftriaxone as definitive therapy for MSSA bacteremia during the study period. We have confirmed the cefoxitin-predicted MSSA susceptibility to cefazolin, but have found concerning drifts in ceftriaxone susceptibilities by continued in vitro monitoring over the last 6 years.

Topics: Anti-Bacterial Agents; Bacteremia; Cefazolin; Cefoxitin; Ceftriaxone; Disk Diffusion Antimicrobial Tests; Humans; Methicillin-Resistant Staphylococcus aureus; Staphylococcal Infections; Staphylococcus aureus

Ivermectin is an endectocide against many parasites. Though being a macrocyclic lactone, its activity against bacteria has been less known, possibly due to the fact that micromolar concentrations at tissue levels are required to achieve a therapeutic effect. Among pathogenic bacteria of major medical significance,. Twenty-one clinical isolates of. The results showed that ivermectin but not levamisole or albendazole exhibited a potent anti-staphylococcal activity at the concentrations of 6.25 and 12.5 μg/ml against two isolates. Interestingly, one of the isolate was sensitive while the other was resistant to methicillin/cefoxitin.. Our novel findings indicate that ivermectin has an anti-bacterial effect against certain

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Cattle; Cefoxitin; Humans; Ivermectin; Kinetics; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Milk; Pakistan; Staphylococcal Infections; Staphylococcus aureus

Methicillin-resistant

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactam Resistance; beta-Lactamases; Cefoxitin; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Retrospective Studies; Staphylococcal Infections

The aim of the study was to validate whether rapid antimicrobial susceptibility testing (AST) by very early reading of disc diffusion tests would provide reliable results in daily routine work. A total of 264 positive blood culture bottles were examined, of which 178 were examined as part of the daily routine workflow. Enterobacterales were evaluated for resistance to cefotaxime, ceftazidime, gentamicin and ampicillin. Staphylococcus aureus (S. aureus) was tested for resistance to cefoxitin as a marker of methicillin-resistant S. aureus (MRSA). The zones were read after 3 h, and if there was insufficient growth, 30 and 60 min later. The results were compared to standard overnight AST. For ampicillin, gentamicin and cefoxitin, there were no errors. For cefotaxime, there were three minor (1.5%), three major (1.5%) and no very major errors. For ceftazidime, there were 13 minor (6.5%) errors only. With the exception of one minor error, all errors were ESBL-A- or AmpC-producing isolates where rapid AST showed a higher degree of resistance than standard AST. This low-cost method may contribute to early effective antibacterial treatment by providing reliable results of AST within 3-4 h. Special breakpoints for early reading are a prerequisite.

Topics: Ampicillin; Anti-Bacterial Agents; Bacteremia; Blood Culture; Cefotaxime; Cefoxitin; Ceftazidime; Diagnostic Errors; Disk Diffusion Antimicrobial Tests; Drug Resistance, Bacterial; Early Diagnosis; Enterobacteriaceae; Enterobacteriaceae Infections; Gentamicins; Humans; Methicillin-Resistant Staphylococcus aureus; Staphylococcal Infections; Time Factors

Here, 210 healthy participants including community personnel (70), clinical students (68), and healthcare workers (HCWs) (72) from the eastern region of Saudi Arabia were studied. Sixty-three

Topics: Adult; Anti-Bacterial Agents; Cefoxitin; Cross Infection; Female; Health Personnel; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Nasal Cavity; Saudi Arabia; Staphylococcal Infections; Students; Young Adult

The aim of the study was to characterize clinical and environmental Staphylococcus pettenkoferi isolates with regard to genomic diversity and antibiotic susceptibility pattern. Repetitive-sequence-based PCR and core genome phylogenetic analysis of whole-genome sequencing (WGS) data verified the presence of distinct clades comprising closely related S. pettenkoferi isolates from different geographical locations and origins.. Phylogenetic relationships between 25 S. pettenkoferi isolates collected from blood cultures and intra-operative air sampling were determined by repetitive-sequence-based PCR typing and analysis of ~157 000 SNPs identified in the core genome after WGS. Antibiotic susceptibility testing and tests for biofilm production (microtitre plate assay) were performed.. Repetitive-sequence-based PCR as well as WGS data demonstrated the close relatedness of clinically significant blood culture isolates to probable contaminants, as well as to environmental isolates. Antibiotic-susceptibility testing demonstrated a low level of antimicrobial resistance. The mecA gene was present in two cefoxitin-resistant isolates. No isolates were found to produce biofilm.. Close genomic relatedness of S. pettenkoferi isolates from different geographical locations and origins were found within clades, but with substantial genomic difference between the two major clades. The ecological niche of S. pettenkoferi remains unconfirmed, but the presence of S. pettenkoferi in the air of the operating field favours the suggestion of a role in skin flora. Identification of S. pettenkoferi in clinical samples should, in a majority of cases, most likely be regarded as a probable contamination, and its role as a possible pathogen in immunocompromised hosts remains to be clarified.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Biofilms; Cefoxitin; Drug Resistance, Bacterial; Genome, Bacterial; Humans; Microbial Sensitivity Tests; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus

Bovine mastitis causes important economic losses in the dairy industry. Coagulase-negative staphylococci (CNS) are a group of bacteria commonly isolated from bovine mastitis and can display resistance to a wide range of antimicrobial agents.. The objective of this study was to determine staphylococcal resistance towards β-lactam, macrolide and lincosamide antimicrobials in quarters previously treated with third-generation cephalosporin and after lincosamide intramammary therapy.. Sick quarters of eighteen cows from Villaguay, Entre Ríos (Argentina) with clinical mastitis were studied. All staphylococcal isolates were tested by disk diffusion for their antimicrobial susceptibilities. Cefoxitin resistance was investigated by PCR and sequencing for both the mecA and mecC genes.. Resistances to penicillin, oxacillin and cefoxitin were observed, whereas no resistance to macrolide and lincosamide was detected. A cefoxitin-resistant Staphylococcus saprophyticus was found to be mecA-negative but mecC-positive.. This study reports for the first time the mecC gene from a CNS in bovine mastitis in South America. Because CNS may act as reservoirs of antimicrobial resistance genes, they can be seen as a potential public health threat with respect to antimicrobial resistance and the development of multiple resistance. Also, the emergence of methicillin-resistant phenotypes will limit therapeutic options.

Topics: Animals; Anti-Bacterial Agents; Argentina; Bacterial Proteins; beta-Lactams; Cattle; Cefoxitin; Drug Resistance, Bacterial; Female; Lincosamides; Macrolides; Mastitis, Bovine; Microbial Sensitivity Tests; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus saprophyticus

β-lactam antibiotics target penicillin-binding proteins (PBPs) preventing peptidoglycan synthesis and this inhibition is circumvented in methicillin resistant Staphylococcus aureus (MRSA) strains through the expression of an additional PBP, named PBP2A. This enzyme is encoded by the mecA gene located within the Staphylococcal Chromosome Cassette mec (SCCmec) mobile genetic element, of which there are 12 types described to date. Previous investigations aimed at analysing the synergistic activity of two β-lactams, oxacillin and cefoxitin, found that SCCmec type IV community-acquired MRSA strains exhibited increased susceptibility to oxacillin in the presence of cefoxitin, while hospital-acquired MRSA strains were unaffected. However, it is not clear if these differences in β-lactam resistance are indeed a consequence of the presence of the different SCCmec types. To address this question, we have exchanged the SCCmec type I in COL (HA-MRSA) for the SCCmec type IV from MW2 (CA-MRSA). This exchange did not decrease the resistance of COL against oxacillin and cefoxitin, as observed in MW2, indicating that genetic features residing outside of the SCCmec element are likely to be responsible for the discrepancy in oxacillin and cefoxitin synergy against these MRSA strains.

Topics: Cefoxitin; Community-Acquired Infections; Cross Infection; DNA, Bacterial; Drug Resistance, Bacterial; Drug Synergism; Humans; Interspersed Repetitive Sequences; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Sequence Analysis, DNA; Staphylococcal Infections

Little is known about the characteristics and diseases associated with methicillin-resistant Staphylococcus aureus (MRSA) in nondomestic animals. Four presumptive MRSA isolates, obtained from clinical (n = 3) and surveillance specimens (n = 1) from dwarf (Helogale parvula) and yellow mongooses (Cynictis penicillata) from a United Kingdom zoo, were analyzed by PCR for detection of mecA and mecC-mediated methicillin resistance, and virulence genes. Isolates were genotyped by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) and spa sequence typing. Three isolates, obtained from the dwarf mongooses, carried mecA, tetK, and fexA resistance and virulence genes (icaA, icaD, and sec) and were typed to SCCmec IVa, spa type t899, and clonal complex (CC) 398. The fourth MRSA isolate, obtained from the femoral bone marrow of a yellow mongoose showing postmortem findings consistent with septicemia, carried mecC and was oxacillin/cefoxitin susceptible, when tested at 37°C but showed a characteristic MRSA susceptibility profile at 25°C ± 2°C. Furthermore, this isolate exhibited a different genetic background (SCCmecXI/t843/CC130) and had biofilm-associated genes (bap, icaA, and icaD) and tetK tetracycline resistance genes. This work describes the first isolation of livestock-associated MRSA CC398 from two zoo mongoose species where it was associated with both clinical disease and colonization, and the first isolation of mecC MRSA from a zoo species in the United Kingdom. Both reports highlight the potential for zoo species to act as reservoirs for these zoonotic agents.

Topics: Animals; Animals, Zoo; Anti-Bacterial Agents; Cefoxitin; Clone Cells; Female; Gene Expression; Genes, Bacterial; Genotype; Herpestidae; Male; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Multilocus Sequence Typing; Staphylococcal Infections; United Kingdom; Virulence Factors

The aim of the study was to compare the effectiveness of Cefoxitin with that of Methicillin/Oxacillin in the determination of mecAgene in Methicillin resistant Coagulase-negative staphylococci(CoNS). We assessed 57 CoNS isolates for mecA gene via PCR, which were subsequently subjected to Methicillin/Oxacillin and Cefoxitin disc diffusion test. These methods are simple, inexpensive and easily available compared to PCR despite less specificity. Out of 41 mecApositive species, 33 (80.5%) were resistant to Methicillin/Oxacillin. Cefoxitin-resistance was seen in all 41 (100%) mecApositive samples. Two (12.5%) mecAnegative isolates of S.saprophyticuswere Methicillin/Oxacillin resistant, but were Cefoxitin sensitive. Four (9.7%) isolates of S.saprophyticus, three (7.3%) of S.epidermidisspecies, and one (2.4%) S.haemolyticusthat were mecApositive were sensitive to Methicillin/Oxacillin but resistant to Cefoxitin. Cefoxitin resistance provides a more accurate picture of mecAgene positivity as compared to Methicillin and Oxacillin.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Coagulase; Drug Resistance, Bacterial; Genes, Bacterial; Humans; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Polymerase Chain Reaction; Predictive Value of Tests; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus

Topics: Animals; Anti-Bacterial Agents; Automation, Laboratory; Cefoxitin; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Sensitivity and Specificity; Staphylococcal Infections

Vancomycin heteroresistance in coagulase negative Staphylococci (CoNS) is a recent health concern especially in serious infections like bloodstream infections as it may lead to failure of therapy. Little information is available about the prevalence vancomycin heteroresistance in CoNS causing bloodstream infections in intensive care units (ICUs) patients of Mansoura University Hospitals (MUHs).. This prospective study enrolled 743 blood samples collected from ICUs patients presented with clinical manifestations of bloodstream infections over the period extending from January 2014 to March 2016. Samples were processed, coagulase negative Staphylococci were identified by routine microbiological methods and the absence of coagulase activity. Species were identified by API Staph 32. Oxacillin resistant CoNS were identified by cefoxitin disc diffusion method. Susceptibility testing of isolated CoNS to vancomycin was carried out using vancomycin agar dilution method. Mec A gene detection by PCR was done for oxacillin resistant isolates. Screening for vancomycin heteroresistance was done on brain heart infusion (BHI) agar containing 4 μg/mL vancomycin. Confirmation of vancomycin heteroresistance was carried out by population analysis profile (PAP).. A total of 58 isolates were identified as CoNS from patients of clinically suspected bloodstream infections. The identified species were 33 (56.9%) Staphylococcus epidermidis, 12 (20.7%) Staphylococcus capitis, 7 (12.1%) Staphylococcus haemolyticus, and 3 isolates (5.2%) Staphylococcus lugdunesis. Three isolates were unidentified by API Staph 32. Forty-four (75.9%) isolates were oxacillin resistant. Mec A gene was detected in all oxacillin resistant isolates. All isolates had susceptible vancomycin MICs by agar dilution. Nine isolates (15.5%) could grow on BHI agar containing 4 μg/mL vancomycin. These isolates showed heterogeneous profile of resistance to vancomycin by population analysis profile.. Vancomycin heteroresistant CoNS causing bloodstream infections is growing unrecognized health hazard in ICUs patients. These isolates have susceptible vancomycin MICs. Screening methods are recommended and should be considered to improve clinical outcome in these high risk patients.

Topics: Anti-Bacterial Agents; Bacteremia; Bacterial Proteins; Cefoxitin; Coagulase; Drug Resistance, Bacterial; Egypt; Female; Genes, Bacterial; Hospitals, University; Humans; Intensive Care Units; Male; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Prospective Studies; Staphylococcal Infections; Staphylococcus; Vancomycin; Vancomycin Resistance

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in horses and its zoonotic potential is poorly understood. The objective of this study is to provide data on the prevalence and genetic characteristics of MRSA isolated from horses on farms, at racecourses, and at slaughterhouses in Italy, using standard and molecular methods. In addition, we report the prevalence of MRSA in horse handlers. Among 388 horses tested by nasal swabs, 27 (7%) were positive for MRSA ST398 (t011, t899, t1255) and ST1 (t127). The prevalence of MRSA in horses tested at slaughterhouses was significantly higher (p < 0.001) compared with those tested on farms and racecourses. Five (7%) out of 67 staff members working in close contact with horses (2 from slaughterhouse, 2 from riding stable, and 1 from racecourse) were carriers of MRSA ST398 (t011, t034) and ST1 (t127). The isolates from horses and humans carried SCCmec IVa or V and were pvl negative and pia positive. All the isolates from both horses and humans were resistant to at least two antimicrobial classes. The circulation of MRSA in horses and in humans working in close contact with them should be considered an emerging public health issue. In fact, it represents a potential risk for people who work in close contact with horses, and for horse meat consumers.

Topics: Abattoirs; Animals; Anti-Bacterial Agents; Cefoxitin; Culture Media; Food Safety; Genotyping Techniques; Horses; Humans; Italy; Methicillin-Resistant Staphylococcus aureus; Oxacillin; Prevalence; Public Health; Spain; Staphylococcal Infections

The heterogeneous expression of methicillin resistance in. This is an analytical comparative study conducted among sudanese patients during period from May 2012 to July 2014,. MRSA- latex agglutination was the most accurate test; it showed 100% of both sensitivity and specificity, followed by cefoxitin disc with sensitivity of 98.48% and specificity of 100%. However, both of oxacillin disc and oxacillin resistance screen agar base showed less accurate results, and were affected by incubation periods. Oxacillin disc after 24 h incubation both at 30°C and 35°C showed sensitivity and specificity values of 87.88% and 96.23%, respectively. However, after 48h incubation the test at 30°C showed sensitivity and specificity values of 89.39%, and 94.34%, respectively. At 35°C (48h) it showed values of 89.39%, 92.45% respectively. Specificity of ORSAB was more than oxacillin disc at 35°C after 24h incubation 98.11% and 96.23%, respectively.. MRSA- latex agglutination and cefoxitin disc diffusion tests are recommended for routine detection of MRSA.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Drug Resistance, Bacterial; Humans; Latex Fixation Tests; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections; Temperature

Coagulase-negative staphylococci have become increasingly recognized as the etiological agent of some infections. A significant characteristic of coagulase-negative staphylococci especially strains isolated from animals and clinical samples is their resistance to routinely used antibiotics although, resistant strains isolated from fermented foods have not been fully reported.. A total of two hundred and fifty-five CoNS isolates were subjected to antimicrobial susceptibility test using the disc diffusion technique. The minimum inhibitory concentration of the isolates to the tested antibiotics was determined using the microbroth dilution method. Methicillin resistant strains were confirmed by detection of methicillin resistant genes (mecA) and also employing cefoxitin screening test.. The isolates were confirmed to be methicillin resistant by the detection of mecA genes and the cefoxitin screening test. The isolates demonstrated appreciable resistance to ampicillin (86.7%), sulfomethoxazole-trimethoprim (74.9%), amoxicillin-clavulanic acid (52.5%) and oxacillin (35.7%). Methicillin resistance was exhibited by 13 out of the 255 isolates although no mecA gene was detected. It was also observed that the methicillin resistant isolates were prevalent in these traditional foods; iru, kindirmo, nono and wara.. This study has ameliorated the incidence of multiple antibiotic resistant coagulase-negative staphylococci in Nigerian fermented foods and if not tackled adequately might lead to horizontal transfer of antibiotic resistance from food to man.

Topics: Adenosine; Ampicillin; Animals; Anti-Infective Agents; Bacterial Proteins; Cefoxitin; Coagulase; Fermentation; Food Microbiology; Humans; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Nigeria; Oxacillin; Phenotype; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus

Staphylococcus haemolyticus is a coagulase-negative staphylococcus that is frequently isolated from blood cultures. Here, we report a case of methicillin-susceptible S. haemolyticus that is resistant to teicoplanin (TEC) and heteroresistant to vancomycin (VAN). The isolate was susceptible to cefoxitin and resistant to TEC by Etest. Population analysis profile-area under the curve analysis confirmed the presence of a VAN heteroresistant subpopulation. Next-generation sequencing analysis of the genome revealed the presence of blaZ and msr(A), which encode cross-resistance to macrolide, lincosamide, and streptogramin B, and the quinolone resistance-conferring gene norA. In addition, several amino acid substitutions were observed in the TEC resistance operon tcaRAB, including I3N, I390N, and L450I in tcaA and L44V, G52V, and S87P in tcaR, as well as in the transpeptidase encoding gene walK (D336Y, R375L, and V404A) and L315 and P316 in graS. We hypothesized that this combination of mutations could confer TEC resistance and reduced VAN susceptibility.

Topics: Amino Acid Substitution; Anti-Bacterial Agents; Bacteremia; Biological Variation, Population; Cefoxitin; Disk Diffusion Antimicrobial Tests; Drug Resistance, Bacterial; Female; Genes, Bacterial; Humans; Methicillin; Middle Aged; Mutation, Missense; Operon; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus haemolyticus; Teicoplanin; Whole Genome Sequencing

Staphylococcus pseudintermedius is a coagulase-positive species that colonizes the nares and anal mucosa of healthy dogs and cats. Human infections with S. pseudintermedius range in severity from bite wounds and rhinosinusitis to endocarditis; historically, these infections were thought to be uncommon, but new laboratory methods suggest that their true incidence is underreported. Oxacillin and cefoxitin disk and MIC tests were evaluated for the detection of mecA- or mecC-mediated methicillin resistance in 115 human and animal isolates of the Staphylococcus intermedius group (SIG), including 111 Staphylococcus pseudintermediusand 4 Staphylococcus delphini isolates, 37 of which were mecA positive. The disk and MIC breakpoints evaluated included the Clinical and Laboratory Standards Institute (CLSI) M100-S25 Staphylococcus aureus/Staphylococcus lugdunensis oxacillin MIC breakpoints and cefoxitin disk and MIC breakpoints, the CLSI M100-S25 coagulase-negative Staphylococcus (CoNS) oxacillin MIC breakpoint and cefoxitin disk breakpoint, the CLSI VET01-S2 S. pseudintermedius oxacillin MIC and disk breakpoints, and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) S. pseudintermedius cefoxitin disk breakpoint. The oxacillin results interpreted by the VET01-S2 (disk and MIC) and M100-S25 CoNS (MIC) breakpoints agreed with the results of mecA/mecC PCR for all isolates, with the exception of one false-resistant result (1.3% of mecA/mecC PCR-negative isolates). In contrast, cefoxitin tests performed poorly, ranging from 3 to 89% false susceptibility (very major errors) and 0 to 48% false resistance (major errors). BD Phoenix, bioMérieux Vitek 2, and Beckman Coulter MicroScan commercial automated susceptibility test panel oxacillin MIC results were also evaluated and demonstrated >95% categorical agreement with mecA/mecC PCR results if interpreted by using the M100-S25 CoNS breakpoint. The Alere penicillin-binding protein 2a test accurately detected all mecA-positive isolates, although for four isolates, cefoxitin induction was required prior to testing. These data demonstrate that the cefoxitin surrogate test does not reliably detect the presence of mecA in S. pseudintermedius isolates and that laboratories should perform oxacillin disk or MIC tests of these isolates when they are encountered.

Topics: Animals; Cefoxitin; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus intermedius

Bacteria of the genus Staphylococcus are one of the major pathogens causing bovine mastitis. In recent decades, resistance of this genus to oxacillin (methicillin) has been a matter of concern due to the possibility of reducing the effectiveness of mastitis treatments and the transfer of resistance determinants to other bacteria. Oxacillin resistance was studied in 170 staphylococci from bovine milk samples, including 79 Staphylococcus aureus and 91 coagulase-negative staphylococci (CNS). The susceptibility profile of 10 antimicrobial agents used in veterinary practice was determined by the Etest method. In addition to the Etest, the phenotypic characterization of oxacillin resistance was tested using the cefoxitin disk diffusion test. All isolates were screened by PCR to detect the mecA gene in 2 different regions of the gene. The isolates with an oxacillin minimum inhibitory concentration ≥0.5 µg/mL or resistant to cefoxitin were identified by sequencing a 536-bp fragment of the 16S rRNA gene. This group of isolates was also evaluated for the presence of blaZ and mecC genes. Molecular analysis of the mecA gene was carried out by typing of the staphylococcal cassette chromosome mec (SCCmec). The relatedness of the mecA-positive isolates was evaluated by macrorestriction of chromosomal DNA followed by pulsed-field gel electrophoresis. With the exception of penicillin and oxacillin, 86% of the isolates showed susceptibility to cephalothin, gentamicin, erythromycin, sulfonamide, trimethoprim-sulfamethoxazole, and tetracycline. All S. aureus isolates were susceptible to oxacillin, whereas 47% (n=43) of the CNS isolates were resistant. The CNS isolates showed a higher resistance to cephalothin, erythromycin, tetracycline, and gentamicin in comparison with S. aureus. The mecA gene was only detected in 10 CNS isolates, identified as Staphylococcus epidermidis, and classified into 3 pulsotypes (A, B, and C) and 4 subtypes (A1, B1, B2, and B3). Among the isolates with an oxacillin resistance phenotype, 12 were positive for the blaZ gene, and 9 of them were mecA-positive. Two of the oxacillin-resistant isolates amplified the mecA homolog gene of Staphylococcus sciuri and none amplified mecC. Three SCCmec types, I, IV, and V, were found. Our results suggest that Staphylococcus epidermidis can be a reservoir for mecA for other Staphylococcus species. Studies investigating the molecular and phenotypic profile of antimicrobial resistance in staphylococcal species shou

Topics: Animals; Anti-Bacterial Agents; Brazil; Cattle; Cefoxitin; Female; Mastitis, Bovine; Methicillin Resistance; Microbial Sensitivity Tests; Milk; Oxacillin; Penicillin G; RNA, Ribosomal, 16S; Staphylococcal Infections; Staphylococcus epidermidis

Staphylococcus aureus small-colony variants (SCVs) emerge frequently during chronic infections and are often associated with worse disease outcomes. There are no standardized methods for SCV antibiotic susceptibility testing (AST) due to poor growth and reversion to normal-colony (NC) phenotypes on standard media. We sought to identify reproducible methods for AST of S. aureus SCVs and to determine whether SCV susceptibilities can be predicted on the basis of treatment history, SCV biochemical type (auxotrophy), or the susceptibilities of isogenic NC coisolates. We tested the growth and stability of SCV isolates on 11 agar media, selecting for AST 2 media that yielded optimal SCV growth and the lowest rates of reversion to NC phenotypes. We then performed disk diffusion AST on 86 S. aureus SCVs and 28 isogenic NCs and Etest for a subset of 26 SCVs and 24 isogenic NCs. Growth and reversion were optimal on brain heart infusion agar and Mueller-Hinton agar supplemented with compounds for which most clinical SCVs are auxotrophic: hemin, menadione, and thymidine. SCVs were typically nonsusceptible to either trimethoprim-sulfamethoxazole or aminoglycosides, in accordance with the auxotrophy type. In contrast, SCVs were variably nonsusceptible to fluoroquinolones, macrolides, lincosamides, fusidic acid, and rifampin; mecA-positive SCVs were invariably resistant to cefoxitin. All isolates (both SCVs and NCs) were susceptible to quinupristin-dalfopristin, vancomycin, minocycline, linezolid, chloramphenicol, and tigecycline. Analysis of SCV auxotrophy type, isogenic NC antibiograms, and antibiotic treatment history had limited utility in predicting SCV susceptibilities. With clinical correlation, this AST method and these results may prove useful in directing treatment for SCV infections.

Topics: Aminoglycosides; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Fluoroquinolones; Fusidic Acid; Humans; Lincosamides; Macrolides; Microbial Sensitivity Tests; Penicillin-Binding Proteins; Rifampin; Staphylococcal Infections; Staphylococcus aureus; Trimethoprim, Sulfamethoxazole Drug Combination

The prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) in Africa is sparsely documented. In Zimbabwe there is no routine patient or specimen screening for MRSA. The aim of this study was to document the presence and epidemiology of MRSA in Zimbabwe.. The study was done in one private sector laboratory with a national network that serves both public and private hospitals. The sample population included in-patients and outpatients, all ages, both genders, all races and only one positive specimen per patient was counted. Specimens testing positive for Staphylococcus aureus in this laboratory were further tested for MRSA using cefoxitin, by standard laboratory procedures. Data was collected from 1(st) June 2013 to 31(st) May 2014.. MRSA was positive in 30 of 407 [7.0%] cases of Stapylococcus aureus reported from the laboratory. All age groups were affected from neonates to geriatrics. All specimens had similar antibiotic susceptibility pattern. Resistance was high for most widely used drugs in Zimbabwe with high sensitivity to vancomycin, linezolid and teicoplanin.. Although there are no recent reports in the literature of the presence of MRSA in Zimbabwe, this study documented a 7.0% prevalence. Resistance to common antibiotics is high and antibiotic oversight is required to control the emergence of resistance to these few expensive drugs.. Study was supported by Department of Anaesthesia and Critical Care funds.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Cefoxitin; Child; Child, Preschool; Drug Resistance, Bacterial; Female; Humans; Infant; Infant, Newborn; Linezolid; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Prevalence; Staphylococcal Infections; Teicoplanin; Vancomycin; Young Adult; Zimbabwe

Staphylococcus aureus isolates with discordant susceptibility results between oxacillin and cefoxitin obtained using automated microbiology systems are infrequently observed. From April 2013 to December 2014, 1956 methicillin-resistant S. aureus (MRSA) and 1761 methicillin-susceptible S. aureus isolates were obtained from different patients. Forty isolates (1.1% and 2% in case of S. aureus and MRSA, respectively) with discordant susceptibility results (oxacillin susceptible and cefoxitin resistant) and carrying mecA gene were obtained. Except 2 SCCmec type IV isolates, 38 MRSA isolates were all SCCmec type V (V

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Cefoxitin; Child; Child, Preschool; Female; Genotype; Humans; Infant; Infant, Newborn; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Oxacillin; Staphylococcal Infections; Taiwan; Young Adult

Forty-four mecA-positive and eight mecA-negative Staphylococcus aureus isolates confirmed by PCR were further tested by disc-diffusion (DD) oxacillin and cefoxitin, oxacillin Epsilon (E)-test, and oxacillin and cefoxitin minimal inhibitory concentration (MIC) Strip methicillin-resistant phenotype in S. aureus (MRSA) tests. Among 44 mecA-positive S. aureus isolates, two (4·5%) were detected as MRSA by DD-oxacillin, 17 (38·6%) by DD-cefoxitin test, and seven (15·9%) by the E-test. In the cefoxitin MIC Strip MRSA test, 19 (43·2%) isolates were resistant. In the oxacillin MIC Strip MRSA test, 18 (40·9%) isolates were resistant and 26 (59·1%) were sensitive, i.e. oxacillin-sensitive MRSA (OS-MRSA) (MIC range 0·25-≤0·25 mg/l). Fifteen out of 26 OS-MRSA (57·7%) belonged to spa-CC 355/595, 78% of which belonged to the largest PFGE clone. Some discrepancies between the phenotypic methods for MRSA identification obtained in this study were caused by large proportion of OS-MRSA. Misidentification of OS-MRSA as MSSA might result in an appearance of highly resistant MRSA in patients treated with beta-lactam antibiotics.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Bosnia and Herzegovina; Cefoxitin; Disk Diffusion Antimicrobial Tests; False Positive Reactions; Genes, Bacterial; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Polymerase Chain Reaction; Staphylococcal Infections

During a 1-year period, 87 methicillin-resistant Staphylococcus aureus isolates were collected from 4 major Cuban hospitals for epidemiological analysis. The majority (86%) were related to the community-associated USA300 clone, whereas the remaining belonged to a new clone ST72-V. Interestingly, no hospital-associated clone was found in these Cuban hospitals.

Topics: Adolescent; Adult; Aged; Cefoxitin; Community-Acquired Infections; Cuba; Female; Hospitals; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Molecular Epidemiology; Staphylococcal Infections; Young Adult

Small-colony variants (SCVs) are slow-growing subpopulations of various auxotrophic bacterial strains. Thymidine-dependent SCVs (TD-SCVs) are unable to synthesize thymidine; hence, these variants fail to grow in a medium without thymidine. In this study, we used 10 TD-SCVs of Staphylococcus aureus, of which four strains possessed mecA. We compared the efficacy of a newly modified medium containing thymidine for the detection of TD-SCVs of methicillin-resistant S. aureus (MRSA) to the efficacy of routinely used laboratory media. We observed that none of the 10 TD-SCVs of S. aureus grew in Mueller-Hinton agar, and four TD-SCVs of MRSA failed to grow on all MRSA screening media, except for the ChromID™ MRSA medium. Laboratory tests conducted using medium with thymidine incorporated showed that thymidine did not affect the minimum inhibitory concentrations of oxacillin and cefoxitin for clinical isolates of S. aureus, and was able to detect MRSA, including TD-SCVs. These findings showed that thymidine-incorporated media are able to detect TD-SCVs of MRSA without altering the properties of other clinically isolated MRSA strains.

Topics: Agar; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Culture Media; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Pilot Projects; Staphylococcal Infections; Thymidine

Methicillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene (mecC-MRSA) exhibited at 37°C MICs of oxacillin close to those of methicillin-susceptible S. aureus (MSSA). We investigated whether at this temperature, mecC-MRSA strains respond to flucloxacillin treatment like MSSA strains, using a rat model of endocarditis. Flucloxacillin (human-like kinetics of 2 g intravenously every 6 h) cured 80 to 100% of aortic vegetations infected with five different mecC-MRSA strains. These results suggest that mecC-MRSA infections may successfully respond to treatment with β-lactams.

Topics: Animals; Anti-Bacterial Agents; Aorta; Cefoxitin; Chromatography, Micellar Electrokinetic Capillary; Endocarditis, Bacterial; Floxacillin; Infusion Pumps; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Rats; Staphylococcal Infections; Temperature

Cefoxitin is a potent inducer of the mecA gene. It is currently as a screening recommended method for presumptive identification of isolates of methicillin resistant Staphylococcus aureus (MRSA). The aim of the study was to compare the sensitivity and specificity of the cefoxitin disc diffusion (30 μg) to oxacillin agar screening from detection of the mecA gene by PCR.. Three hundred thirty-one strains of S. aureus isolated from blood cultures of patients from hospitals in Lima were used in the study. The following tests were performed: oxacillin screening agar (plates were inoculated with 4% NaCl and 6 mg/L of oxacillin), cefoxitin disc diffusion test (30 ug) and PCR to amplify the mecA gene.. The mecA gene was detected in 165 out of 331 S. aureus isolates. Thus, the frequency of detection of MRSA was 50%. The evaluation of the cefoxitin disc diffusion test showed a 96.3% and 90.9% of sensitivity and specificity, respectively.. Cefoxitin disc diffusion test correlated well with detection of the mecA gene by PCR. Therefore, this test can be an alternative to PCR for detection of MRSA in limited resources settings.

Topics: Adenosine; Anti-Bacterial Agents; Cefoxitin; False Positive Reactions; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Phenotype; Polymerase Chain Reaction; Staphylococcal Infections

Staphylococcus pseudintermedius is an opportunistic pathogen recognized as the leading cause of skin, ear, and post-operative bacterial infections in dogs and cats. Zoonotic infections have also recently been reported causing endocarditis, infection of surgical wounds, rhinosinusitis, and catheter-related bacteremia. The aim of the present study is to evaluate, for the first time, the pathogenic potential of S. pseudintermedius isolated from a human infection. To this end, strain DSM 25713, which was recently isolated from a wound of a leukemic patient who underwent a bone marrow transplantation, was investigated for biofilm formation and antibiotic-resistance under conditions relevant for wound infection.. The effect of pH (5.5, 7.1, and 8.7) and the presence of serum (diluted at 1:2, 1:10, and 1:100) on biofilm formation was assessed through a crystal violet assay. The presence of serum significantly reduced the ability to form biofilm, regardless of the pH value tested. In vitro activity of eight antibiotics against biofilm formation and mature 48 h-old biofilms was comparatively assessed by crystal violet assay and viable cell count, respectively. Antibiotics at sub-inhibitory concentrations reduced biofilm formation in a dose-dependent manner, although cefoxitin was the most active, causing a significant reduction already at 1/8xMIC. Rifampicin showed the highest activity against preformed biofilms (MBEC90: 2xMIC). None of the antibiotics completely eradicated the preformed biofilms, regardless of tested concentrations. Confocal and electron microscopy analyses of mature biofilm revealed a complex "mushroom-like" architecture consisting of microcolonies embedded in a fibrillar extracellular matrix.. For the first time, our results show that human wound-associated S. pseudintermedius is able to form inherently antibiotic-resistant biofilms, suggestive of its pathogenic potential, and consistent with recent reports of zoonotic infections.

Topics: Anti-Bacterial Agents; Biofilms; Cefoxitin; Drug Resistance, Multiple, Bacterial; Humans; Hydrogen-Ion Concentration; Rifampin; Staphylococcal Infections; Staphylococcus; Surgical Wound Infection

Detection and identification of methicillin-resistant Staphylococcus aureus (MRSA) in clinical microbiology laboratories are important for the selection of appropriate treatment and obtaining epidemiological data. mecC gene, is a mecA homologue, showing almost 69% DNA similarity with the mecA gene and the encoded protein by this gene shows almost 63% similarity with the PBP2a/2' protein. Several studies indicated that mecC positive MRSA strains can be transmitted from the livestock to humans by cross contamination. Panton-Valentine leukocidin (PVL), a potent cytotoxin of S.aureus is also considered as an important virulence factor. The aim of this study was to determine the existence and prevalence of mecC and pvl genes among S.aureus strains isolated from clinical specimens. A total of 1700 S.aureus isolates including 1177 methicillin-susceptible S.aureus (MSSA) and 523 MRSA, isolated in our hospital between January 2007 to December 2014, were included in the study. The isolates were identified by both conventional methods and BD Phoenix automated system (BD Diagnostic Instrument Systems, USA). Antibiotic susceptibility testing was performed by Kirby-Bauer disk diffusion method with oxacillin (1 μg) and cefoxitin (30 μg) according to the CLSI standards. The presence of mecA gene was investigated by the use of real-time PCR, and the presence of pvl and mecC genes were detected by conventional PCR method. Among the patients, 44.6% (759/1700) were outpatients, 65.8% (1119/1700) were male and the mean age of of patients was 39.7 years. Of 1700 isolates evaluated in this study, 523 (30.7%) were positive for mecA gene, however all of them were negative for mecC gene. A total of 32 (1.8%) isolates were positive for pvl gene including 23 (1.9%) out of 1177 MSSA and nine (1.7%) out of 523 MRSA strains. Eighteen (56.2%) of the PVL-positive S.aureus strains were isolated from skin and soft tissue infections. The frequency of PVL detected in this study was similar to the data of previous studies in our country. To the best of our knowledge, this is the first study for the determination of the mecC in our country. Although the mecC gene positive S.aureus has not been detected in our study, it should be kept in mind that the regional epidemiological conditions can vary quickly. In conclusion, multicenter studies are needed for the screening of mecC gene including the animal isolates, in Turkey.

Topics: Adult; Anti-Bacterial Agents; Bacterial Proteins; Bacterial Toxins; Cefoxitin; Exotoxins; Female; Humans; Leukocidins; Male; Methicillin-Resistant Staphylococcus aureus; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections

We aimed to characterise the staphylococcal cassette chromosome mec (SCCmec) type, genetic relatedness, biofilm formation and composition, icaADBC genes detection, icaD expression, and antibiotic susceptibility of planktonic and biofilm cells of Staphylococcus hominis isolates from blood.. The study included 67 S. hominis blood isolates. Methicillin resistance was evaluated with the cefoxitin disk test. mecA gene and SCCmec were detected by multiplex PCR. Genetic relatedness was determined by pulsed-field gel electrophoresis. Biofilm formation and composition were evaluated by staining with crystal violet and by detachment assay, respectively; and the biofilm index (BI) was determined. Detection and expression of icaADBC genes were performed by multiplex PCR and real-time PCR, respectively. Antibiotic susceptibilities of planktonic cells (minimum inhibitory concentration, MIC) and biofilm cells (minimum biofilm eradication concentration, MBEC) were determined by the broth dilution method.. Eighty-five percent (57/67) of isolates were methicillin resistant and mecA positive. Of the mecA-positive isolates, 66.7% (38/57) carried a new putative SCCmec type. Four clones were detected, with two to five isolates each. Among all isolates, 91% (61/67) were categorised as strong biofilm producers. Biofilm biomass composition was heterogeneous (polysaccharides, proteins and DNA). All isolates presented the icaD gene, and 6.66% (1/15) isolates expressed icaD. This isolate presented the five genes of ica operon. Higher BI and MBEC values than the MIC values were observed for amikacin, vancomycin, linezolid, oxacillin, ciprofloxacin, and chloramphenicol.. S. hominis isolates were highly resistant to methicillin and other antimicrobials. Most of the detected SCCmec types were different than those described for S. aureus. Isolates indicated low clonality. The results indicate that S. hominis is a strong biofilm producer with an extracellular matrix with similar composition of proteins, DNA and N-acetylglucosamine; and presents high frequency and low expression of icaD gene. Biofilm production is associated with increased antibiotic resistance.

Topics: Amidohydrolases; Anti-Bacterial Agents; Bacteremia; Bacterial Proteins; Biofilms; Cefoxitin; Chromosomes, Bacterial; Ciprofloxacin; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Humans; Methicillin; Microbial Sensitivity Tests; Operon; Oxacillin; Penicillin-Binding Proteins; Phylogeny; Plankton; Staphylococcal Infections; Staphylococcus hominis; Vancomycin

The development of persistent antibiotic resistance by human methicillin-sensitive Staphylococcus aureus (MSSA) strains and substantial association with poly-N-acetyl glucosamine (PNAG) in biofilms is reported in this investigation. Sixteen of 31 MSSA strains under study were found to have developed resistance to one or more antibiotics, with four strains, two of which did not produce biofilms, showing resistance to cefoxitin, undetectable by mecA amplification. Antibiotic resistance displayed by 13/14 biofilm-forming S. aureus isolates remained persistent for 4 weeks prior to reverting back to the original antibiotic susceptibility, prompting a suggestion of determining antibiograms for clinical S. aureus isolates subcultured from biofilms developed in vitro as well as planktonic subcultures prepared from the site of infection. While there was correlation of antibiotic resistance with biofilm formation confirming previous reports, this is the first time that persistence of the biofilm-associated antibiotic resistance by S. aureus as planktonic cells is reported. Among the two methods used for assessment of biofilm formation, the tissue culture plate (TCP) method revealed that almost all strains were strong or moderate biofilm producers whereas only 19/31 strains were biofilm producers using the Congo Red agar (CRA) method indicating the superiority of the TCP method in detecting biofilm producers. We also observed no association between biofilm formation and major capsule types. However, substantial, although not absolute, association of biofilm formation with PNAG was observed, warranting continued identification of additional surface-associated polysaccharide and/or protein antigens associated with biofilm formation for development of an effective vaccine against S. aureus infections regardless of capsular phenotype.

Topics: Acetylglucosamine; Anti-Bacterial Agents; Bacterial Adhesion; Bacterial Capsules; Bacterial Proteins; Biofilms; Cefoxitin; Drug Resistance, Bacterial; Gene Expression; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Penicillin-Binding Proteins; Plankton; Staphylococcal Infections

Methicillin-resistant Staphylococcus aureus (MRSA) strains carrying the mecC gene have been reported from humans and animals from several European countries, but never from Spain. We describe the first isolates of mecC-positive MRSA of human origin collected in Spain and report a fatal case of bacteraemia.. Isolates were tested for phenotypic resistance using cefoxitin, tested for the mecA/mecC genes and toxin genes by PCR, and typed by staphylococcal cassette chromosome mec (SCCmec), PFGE, spa, multilocus sequence typing and agr.. During 2008-13 five MRSA isolates showing resistance to cefoxitin and carrying the mecC gene were recovered at one hospital in Spain. In a review of 5505 S. aureus strains received at the Spanish National Reference Centre for Staphylococci from the same period, we found two additional mecC-positive isolates. The isolates were recovered from blood (two), wounds (two), joint fluid (one), urine (one) and a nasal swab (one). All MRSA were mecA negative, presented SCCmecXI, belonged to agr group III and to clonal complex 130, and were negative for the production of the toxin genes tst1, eta, etb, etd and Panton-Valentine leucocidin. Six isolates belonged to spa type t843 (ST130 and ST1945, where ST stands for sequence type) and one to spa type t6220 (ST1945). One patient with mecC-positive MRSA sepsis died in the emergency department.. We confirm the presence of MRSA carrying the mecC gene in Spain, the ability of this livestock-associated MRSA to cause severe infections in humans and the need to perform culture-based susceptibility testing methods in order to detect these emerging strains.

Topics: Aged; Aged, 80 and over; Animals; Anti-Bacterial Agents; Bacteremia; Bacterial Proteins; Cefoxitin; Child, Preschool; DNA, Bacterial; Fatal Outcome; Female; Genotype; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Molecular Typing; Polymerase Chain Reaction; Spain; Staphylococcal Infections; Virulence Factors

This study aimed to determine the prevalence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) carriage, risk factors of colonization and antimicrobial susceptibility patterns of S. aureus strains. The study was conducted at the Muhimbili National Hospital in Dar es Salaam, Tanzania. Nasal swabs were obtained from children and S. aureus was isolated and identified using conventional culture methods. MRSA was screened and confirmed using the cefoxitin disk and multiplex real-time polymerase chain reaction, respectively. Antibiotic susceptibility was performed using the Kirby-Bauer disk diffusion method. MRSA isolates were further characterized by pulsed field gel electrophoresis (PFGE) profiling. Of 285 children included in the study, S. aureus was detected in 114 (40%). Of the 114 isolates, 12 (10.5%) were MRSA. PFGE results showed that these MRSA isolates are epidemiologically unrelated. Resistance of all S. aureus to trimethoprim-sulfamethoxazole, tetracycline, gentamicin, and ciprofloxacin was 65.8%, 23.7%, 27.2%, and 4.4%, respectively. No resistance to vancomycin was found. The prevalence of inducible clindamycin resistance, constitutive clindamycin resistance, MS phenotype (resistance to erythromycin alone), and multidrug resistance was 16.7%, 1.8%, 14.0%, and 16.8%, respectively. None of the risk factors examined was found to be significant. This is the first report of S. aureus and nasal carriage of MRSA and a high rate of S. aureus carriage was found in Tanzanian under-5 children. The study findings support the need for proper health education and effective infection control measures for healthcare workers.

Topics: Anti-Bacterial Agents; Bacterial Typing Techniques; Carrier State; Cefoxitin; Child, Preschool; Clone Cells; Drug Resistance, Multiple, Bacterial; Electrophoresis, Gel, Pulsed-Field; Female; Humans; Infant; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Nasal Cavity; Staphylococcal Infections; Tanzania

To investigate the reliability of cefoxitin and oxacillin for the detection of mecC-positive Staphylococcus aureus.. The susceptibility to cefoxitin and oxacillin of 62 mecC-positive S. aureus isolates was investigated using broth microdilution, agar dilution, Etest and disc diffusion on different types of media. The data were interpreted for the utility of cefoxitin and oxacillin in conjunction with the stated methodologies for the detection of mecC-positive isolates.. Cefoxitin with Mueller-Hinton media from Becton Dickinson and Oxoid detected all mecC-positive isolates when tested by broth microdilution, agar dilution and disc diffusion. By Etest, one isolate was falsely susceptible. Mueller-Hinton agar from bioMérieux was substantially less able to detect these isolates. One isolate was falsely susceptible by agar dilution when using Iso-Sensitest and Columbia agar. Disc diffusion using cefoxitin on Iso-Sensitest agar missed 29% of the isolates. For oxacillin, only agar dilution on Columbia agar + 2% NaCl was able to detect all mecC-positive isolates successfully.. Cefoxitin used with EUCAST methodology and oxacillin used with agar dilution on Columbia agar + 2% NaCl detected all mecC-positive isolates. These methods with their concomitant agars should be preferred over Iso-Sensitest, which is recommended by the BSAC. It should be noted that for disc diffusion Mueller-Hinton media from bioMérieux performed poorly, with 26%-47% of mecC isolates being falsely susceptible.

Topics: Anti-Bacterial Agents; Cefoxitin; Culture Media; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Sensitivity and Specificity; Staphylococcal Infections

Due to the ongoing concern about the reliability of Staphylococcus breakpoints (interpretive criteria) for other β-lactam agents, the Clinical and Laboratory Standards Institute recently approved the elimination of all breakpoints for antistaphylococcal β-lactams except for penicillin, oxacillin or cefoxitin, and ceftaroline. Routine testing of penicillin and oxacillin or cefoxitin should be used to infer susceptibility for all β-lactams with approved clinical indications for staphylococcal infections. It is critical for laboratories to reject requests for susceptibility testing of other β-lactams against staphylococci and to indicate that susceptibility to these agents can be predicted from the penicillin and oxacillin or cefoxitin results. This article reviews β-lactam resistance mechanisms in staphylococci, current antimicrobial susceptibility testing and reporting recommendations for β-lactams and staphylococci, and microbiologic data and clinical data supporting the elimination of staphylococcal breakpoints for other β-lactam agents.

Topics: Anti-Bacterial Agents; beta-Lactam Resistance; beta-Lactams; Cefoxitin; Ceftaroline; Cephalosporins; Humans; Microbial Sensitivity Tests; Oxacillin; Penicillins; Staphylococcal Infections; Staphylococcus; United States; United States Food and Drug Administration

The accurate performance of the Vitek 2 GP67 card for detecting methicillin-resistant coagulase-negative staphylococci (CoNS) is not known. We prospectively determined the ability of the Vitek 2 GP67 card to accurately detect methicillin-resistant CoNS, with mecA PCR results used as the gold standard for a 4-month period in 2012. Included in the study were 240 consecutively collected nonduplicate CoNS isolates. Cefoxitin susceptibility by disk diffusion testing was determined for all isolates. We found that the three tested systems, Vitek 2 oxacillin and cefoxitin testing and cefoxitin disk susceptibility testing, lacked specificity and, in some cases, sensitivity for detecting methicillin resistance. The Vitek 2 oxacillin and cefoxitin tests had very major error rates of 4% and 8%, respectively, and major error rates of 38% and 26%, respectively. Disk cefoxitin testing gave the best performance, with very major and major error rates of 2% and 24%, respectively. The test performances were species dependent, with the greatest errors found for Staphylococcus saprophyticus. While the 2014 CLSI guidelines recommend reporting isolates that test resistant by the oxacillin MIC or cefoxitin disk test as oxacillin resistant, following such guidelines produces erroneous results, depending on the test method and bacterial species tested. Vitek 2 cefoxitin testing is not an adequate substitute for cefoxitin disk testing. For critical-source isolates, mecA PCR, rather than Vitek 2 or cefoxitin disk testing, is required for optimal antimicrobial therapy.

Topics: Cefoxitin; Coagulase; Diagnostic Errors; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus

We evaluated the utility of 2 methods for detection of methicillin-resistant Staphylococcus aureus (MRSA) directly from signal-positive blood culture bottles: loop-mediated isothermal amplification (LAMP) assay, and direct cefoxitin disk diffusion (DCDD) test using a 30 μg cefoxitin disk. In parallel, standard microbiological identification and oxacillin susceptibility testing with MecA PCR was performed. Of 60 blood cultures positive for Gram-positive cocci in clusters, LAMP (via detection of the FemA and MecA genes) showed 100% sensitivity and specificity for identification of MRSA/MSSA. When coagulase-negative staphylococci were tested, sensitivity for detection of methicillin resistance was 91.7% and specificity was 100%. DCDD along with direct tube coagulase assay detected only 80.6% of MRSA/MSSA. LAMP showed higher diagnostic accuracy although DCDD was more cost-effective and did not require additional reagents or supplies.. الكشف المباشر للعنقوديات الذهبية المقاومة للميثيسيلين من خلال التضخيم المتساوي الحرارة بواسطة العروة، واختبارات انتشار قرص السيفوكسيتين المباشر. لبنى متولي، ناهد جمعة، رانيا حسن. قد قامت الباحثات بتقييم فائدة طريقتين للكشف المباشر للعقديات الذهبية المقاومة للميثيسيلين المستمدة من زجاجة زرع الدم الإيجابية العلامة؛ والطريقتان هما المقايسة بالتضخيم المتساوي الحرارة بواسطة العروة، واختبار الانتشار المباشر لقرص وغرام. وأجرت الباحثات بموازاة ذلك اختبارات للكشف المعياري للمكروبات مع الاستجابة للأوكسيسيلين باستخدام التفاعل السلسلي للبوليمراز على مادة .MecA ومن بين 60 زجاجة زرع دم إيجابي للجراثيم المكوَّرة الإيجابية الغرام، تبيَّن أن هناك 100% استجابة ونوعية لكشف التضخيم المتساوي الحرارة بواسطة العروة (عبر كشف جينات FemA و.(MecA وعند إجراء الاختبار على المكورات العنقودية السلبية لإنزيم التخثير (كوأغيولاز) وجدت الباحثات أن حساسية كشف المقاومة للميثيسيلين بلغت 91.7% بينما بلغت النوعية 100% كما أن استخدام الانتشار المباشر لقرص السيفوكسيتين مع المقايسة المباشرة في الأنبوب لإنزيم التخثير لم يكشف إلا 80.6% من الجراثيم العنقودية المقاومة للميثيسيلين، والمستجيبة له. وهكذا اتضح أن التضخيم المتساوي الحرارة بواسطة العروة يوفر دقة تشخيصية أعلى مما يوَّفره الانتشار المباشر لأقراص السيفوكسيتين، وأنه أكثر مردوداً ولا يتطلب إمدادات أو كواشف إضافية.. Détection de Staphylococcus aureus résistant à la méthicilline directement par amplification isotherme induite par boucle et par tests de diffusion sur disque à la céfoxitine directs.. Nous avons évalué l’utilité de deux méthodes de détection de Staphylococcus aureus résistant à la méthicilline directement à partir des flacons d’hémoculture donnant des signaux positifs à l’aide de l’amplification isotherme induite par boucle ainsi que de tests de diffusion sur disque de 30 μg de céfoxitine directs. En parallèle, une identification microbiologique normalisée et un test de sensibilité à l’oxacilline par PCR visant l’amplification du gène MecA ont été réalisés. Sur 60 hémocultures positives pour les cocci à Gram positif en grappes, l’amplification isotherme induite par boucle (au moyen du dépistage des gènes FemA et MecA) a montré une sensibilité et une spécificité de 100 % pour l’identification de Staphylococcus aureus résistant et sensible à la méthicilline. Lorsque les staphylocoques à coagulase négative ont été analysés, la sensibilité pour la détection de la résistance à la méthicilline était de 91,7 % et la spécificité de 100 %. Les tests de diffusion sur disque de céfoxitine directs ainsi que le dosage direct de la coagulase à partir des flacons ont détecté seulement 80,6 % des Staphylococcus aureus résistants/sensibles à la méthicilline. L’amplification isotherme induite par boucle a montré une exactitude diagnostique supérieure, même si les tests de diffusion sur disque à la céfoxitine directs étaient d’un meilleur rapport coût-efficacité et n’exigeaient ni réactifs ni fournitures supplémentaires.

Topics: Cefoxitin; Disk Diffusion Antimicrobial Tests; DNA Fingerprinting; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Drug Resistance, Bacterial; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Penicillin-Binding Proteins; Prevalence; Staphylococcal Infections; Staphylococcus aureus

Staphylococcus aureus infections are increasingly reported from both health institutions and communities around the world. In particular, infections due to methicillin-resistant Staphylococcus aureus (MRSA) strains have been detected worldwide. If MRSA becomes the most common form of S. aureus in a community, it makes the treatment of common infections much more difficult. But, report on the current status of community acquired MRSA in the study area is scanty.. Community-based cross sectional study was conducted to evaluate the current prevalence and antibiotic susceptibility pattern of MRSA among primary school children and prisoners in Jimma town. MRSA was detected using Cefoxitin (30μg) disc; and epidemiologic risk factors were assessed using pre-designed questionnaires distributed to the children's parents and prisoners. A total of 354 nasal swabs were collected from primary school children and prisoners from December 2010 to March 2011 following standards microbiological methods.. A total of 169 S. aureus isolates were recovered. The overall prevalence of MRSA among the study population was 23.08 % (39/169). Specifically, the prevalence of MRSA among primary school children and prisoners were 18.8% (27/144) and 48% (12/25), respectively. The isolated S. aureus and MRSA displayed multiple drug resistance (MDR) to 2 to 10 antibiotics. The most frequent MDR was Amp/Bac/Ery/Pen/Fox (resistance to Ampicillin, Bacitracin, Erythromycin, Penicillin, and Cefoxitin).. The present study revealed that MRSA could be prevalent in the healthy community, transmitted from hospital to the community. The high distribution of MRSA could be favored by potential risk factors. Thus, for comprehensive evaluation of the current prevalence of MRSA and design control measures, consideration need to be given to the healthy community besides data coming from health institutions.

Topics: Adolescent; Adult; Ampicillin; Anti-Bacterial Agents; Carrier State; Cefoxitin; Child; Child, Preschool; Cross Infection; Cross-Sectional Studies; Drug Resistance, Multiple, Bacterial; Ethiopia; Female; Humans; Male; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Prevalence; Prisoners; Risk Factors; Schools; Staphylococcal Infections; Students; Surveys and Questionnaires; Young Adult

Reports of oxacillin-susceptible mecA-positive Staphylococcus aureus strains are on the rise. Because of their susceptibility to oxacillin and cefoxitin, it is very difficult to detect them by using routine phenotypic methods. We describe two such isolates that were detected by chromogenic medium and confirmed by characterization of the mecA gene element.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Bacteriological Techniques; Cefoxitin; Chromogenic Compounds; Culture Media; Humans; Methicillin-Resistant Staphylococcus aureus; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections

In vitro studies demonstrate that oxacillin minimal inhibitory concentrations (MICs) of methicillin-resistant S. aureus (MRSA) strains USA300 and 400 decrease in the presence of cefoxitin. The aim of this study was to characterize the activity of cefoxitin plus β-lactams against a collection of MRSA isolates. We assessed the in vitro antimicrobial activity of a selection of β-lactams alone and together with subinhibitory concentrations of cefoxitin against a collection of MRSA, methicillin-susceptible S. aureus (MSSA), and vancomycin-intermediate S. aureus (VISA) isolates using MICs and time kill assays. For community-associated (CA) MRSA strains USA300 and USA400, MICs of nafcillin, cefazolin, cephalexin, cefuroxime, ceftriaxone and cefotaxime decreased by 8- to 64-times in the presence of 10 μg/ml cefoxitin. In contrast, for hospital-associated (HA) strains COLn, N315, and Mu50, there was no change in any β-lactam MIC in the presence of cefoxitin. When combined with cefoxitin, the cephalexin MIC decreased for eight CA-MRSA and five MSSA sequence types but did not change for seven HA-MRSA sequence types. β-lactam/cefoxitin combinations were synergistic against CA- but not HA-MRSA strains in time kill assays. Cefoxitin combined with a variety of β-lactams enhances their activity against CA-MRSA strains in vitro. Further studies of combination β-lactam therapy may provide insight into β-lactam biology, penicillin binding protein cooperativity, and novel therapeutic strategies against MRSA.

Topics: beta-Lactams; Cefoxitin; Community-Acquired Infections; Cross Infection; Drug Synergism; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Staphylococcal Infections

The increase in antibiotic resistance due to multiple factors has encouraged the search for new compounds which are active against multidrug-resistant pathogens. In this context, chalcones, dihydrochalcones, hydrazones and oxadiazoles were tested against Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus (MRSA) isolates, which were obtained from clinical laboratories and were characterized as MRSA using traditional and molecular methods. Among 65 tested compounds, two chalcones, one dihydrochalcone and two hydrazones were active against MRSA. Based on the minimal inhibitory concentration and cytotoxicity, hydrazones provided a better selectivity index than chalcones. Active hydrazones are promising antibiotic-like substances and they should be the subject of further microbiological studies.

Topics: Animals; Anti-Bacterial Agents; Chalcones; Chlorocebus aethiops; Humans; Hydrazones; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Models, Chemical; Oxadiazoles; Staphylococcal Infections; Staphylococcus aureus; Vero Cells

The objectives of this study were to investigate the relationship between primary care antibiotics prescribed within 2 months and 12 months and the carriage of meticillin-resistant Staphylococcus aureus (MRSA) in nasal flora from a large representative sample of community-resident adults. S. aureus isolates were obtained from nasal samples submitted by UK resident adults aged ≥ 16 years registered with 12 general practices in the former Avon and Gloucestershire health authority areas. Individual-level antibiotic exposure data during the 12 months prior to providing the samples were collected from the primary care electronic records. MRSA status was determined by measuring resistance to cefoxitin. In total, 6937 adults were invited to take part, of whom 5917 returned a nasal sample. S. aureus was identified in 946 samples and a total of 761 participants consented to primary care record review and had complete data for the analyses. There was no evidence of an association between any antibiotic in the previous 2 months and MRSA isolation, with an adjusted odds ratio (aOR) of 1.33 [95% confidence interval (CI) 0.12-15; P=0.8]. There was a suggestion of an association between any antibiotic use in the previous 12 months and MRSA, with an aOR of 2.45 (95% CI 0.95-6.3; P=0.06). In conclusion, there is a suggestion that antibiotics prescribed within 12 months is associated with the carriage of MRSA, but not within 2 months, although the 2-month analysis had fewer data subjects and was therefore underpowered to detect this association. A larger study would be able to clarify these associations further.

Topics: Adult; Aged; Anti-Bacterial Agents; Carrier State; Cefoxitin; Female; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Nose; Prescriptions; Primary Health Care; Staphylococcal Infections; Surveys and Questionnaires; United Kingdom

The recent finding of a new mecA homologue, mecA(LGA251) , with only 70% nucleotide homology to the conventional mecA gene has brought the routine testing for mecA as a confirmatory test for methicillin-resistant Staphylococcus aureus (MRSA) into question. A multiplex PCR was designed to differentiate mecA(LGA251) from the known mecA together with detection of lukF-PV and the spa gene fragments, enabling direct spa typing by sequencing of the PCR amplicons. The PCR analysis and subsequent spa typing were validated on a large collection (n=185) of contemporary MRSA and methicillin-sensitive S. aureus isolates, including 127 isolates carrying mecA(LGA251) . The mecA(LGA251) gene was situated in staphylococcal cassette chromosome mec type XI elements, and sequence variation within a 631-bp fragment of mecA(LGA251) in 79 isolates indicated a very conserved gene sequence. Following a successful validation, the multiplex PCR strategy was implemented in the routine testing of MRSA for national surveillance. Over a 2-month period, among 203 samples tested, 12 new MRSA cases caused by isolates carrying mecA(LGA251) were identified, emphasizing the clinical importance of testing for these new MRSA isolates.

Topics: Bacterial Proteins; Base Sequence; Cefoxitin; Chromosomes, Bacterial; Conserved Sequence; DNA, Bacterial; Genes, Bacterial; Humans; Methicillin-Resistant Staphylococcus aureus; Multilocus Sequence Typing; Penicillin-Binding Proteins; Phenotype; Staphylococcal Infections

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Cattle; Cattle Diseases; Cefoxitin; Germany; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Molecular Typing; Oxacillin; Penicillin-Binding Proteins; Sequence Analysis, DNA; Sequence Homology, Nucleic Acid; Staphylococcal Infections

Cefoxitin disk diffusion susceptibility testing is a recommended screening method for the detection of methicillin resistance in human isolates of Staphylococcus aureus and coagulase-negative staphylococci. A retrospective analysis of 1,146 clinical isolates of Staphylococcus pseudintermedius from dogs was conducted to determine if screening by the cefoxitin disk method can be similarly useful with S. pseudintermedius. The distribution of cefoxitin growth inhibition zone diameters within this collection was bimodal and correlated well with the results of methicillin resistance gene (mecA) detection by polymerase chain reaction. Of the isolates, 5% had discordant results and, when retested, 84% of these were in agreement. While a greater diversity of isolates and interlaboratory comparisons must be tested, the current study suggests that an epidemiological breakpoint (of approximately ≤ 30 mm = resistant; ≥ 31 = susceptible) can be established to predict methicillin resistance in S. pseudintermedius.

Topics: Animals; Cefoxitin; Disk Diffusion Antimicrobial Tests; Dog Diseases; Dogs; Methicillin; Methicillin Resistance; Staphylococcal Infections; Staphylococcus

Twenty-three strains of Staphylococcus aureus with borderline resistance to oxacillin were studied. These strains were not detected by the cefoxitin test, tests for penicillin-binding protein 2a (PBP2a), mecA, and mecA(LGA251) were negative, and the strains were genetically unrelated. To detect all strains resistant to oxacillin, laboratories should routinely test for both cefoxitin and oxacillin.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Cluster Analysis; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Molecular Epidemiology; Molecular Typing; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Tunisia

Methicillin-resistant Staphylococcus aureus (MRSA) infections are difficult and expensive to treat, therefore early detection is essential to avoid treatment failure. Several phenotypic and genotypic methods are used to detect MRSA; however, the method of choice remains problematic. For detection of MRSA we have evaluated 3 different phenotypic methods with the genotypic method ie, polymerase chain reaction (PCR). Detection of mecA gene by PCR is a gold standard for detection of MRSA strains. Methicillin resistance was detected in 280 clinical Staphylococcus aureus isolates by PCR, oxacillin (1 microg) disc diffusion (ODD), oxacillin screen agar (OSA), and cefoxitin (30 microg) disc diffusion (CDD) methods. Out of 280 Staphylococcus aureus strains 145 (51.8%) were mecA gene positive PCR. Sensitivity and specificity of the ODD, OSA and CDD methods were detected as follows: 97.2% and 95.9%, 100% and 94.8%, and 97.8% and 100%, respectively, when compared to PCR for mecA gene. Amongst all 3 phenotypic methods, cefoxitin disc diffusion (CDD) method was best correlated with mecA-PCR. CDD methods could be a good choice for detecting methicillin resistance in S aureus strains in day to day practice where mecA PCR cannot be performed.

Topics: Bacterial Proteins; Cefoxitin; Disk Diffusion Antimicrobial Tests; Genotype; Humans; Methicillin-Resistant Staphylococcus aureus; Oxacillin; Penicillin-Binding Proteins; Phenotype; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections

Topics: Anti-Bacterial Agents; Argentina; Cefoxitin; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections

The Clinical and Laboratory Standards Institute (CLSI) recommends testing coagulase-negative staphylococci (CoNS) strains to determine resistance against oxacillin by testing for mecA, PBP2a, or with cefoxitin disk. However, discrepant results of resistance to oxacillin and susceptibility to cefoxitin were found. In this study, we aimed to investigate the oxacillin resistance and cefoxitin susceptibility of CoNS in Taiwan. Of 9,017 strains collected from 2005 to 2010, 131 (1.5%) of the isolates were oxacillin-resistant and cefoxitin-susceptible. Species identification was carried out using the Vitek 2 system or 16S ribosomal RNA sequencing. Oxacillin minimum inhibitory concentrations (MICs) were examined by the agar dilution method. The presence of mecA and the activity of β-lactamase were performed by polymerase chain reaction (PCR) and Cefinase disks, respectively. Overall, 33% (43/129) of the strains carried mecA and 43% (37/86) of mecA-negative isolates tested positive for β-lactamase. The remaining 49 isolates were negative for both mecA and β-lactamase, and were mainly Staphylococcus cohnii ssp. urealyticus and S. saprophyticus (oxacillin MICs 0.5-2 μg/ml) obtained from bloodstream and urinary tract infections. Our study suggests that incorrect reporting can be found in CoNS using cefoxitin disk alone to determine the susceptibility to oxacillin, and the strains should be further tested for oxacillin MICs and detection of the mecA gene or β-lactamase activity.

Topics: Anti-Bacterial Agents; Bacterial Typing Techniques; beta-Lactam Resistance; Cefoxitin; Coagulase; Genotype; Humans; Microbial Sensitivity Tests; Oxacillin; Polymerase Chain Reaction; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus; Taiwan

The performance of the MicroScan WalkAway PC30 panel for detection of oxacillin resistance was evaluated by use of a collection of 420 staphylococcus isolates. The addition of a cefoxitin test (4 mg/liter) to the oxacillin MIC determination increased its raw performance for Staphylococcus aureus; additional data were required for coagulase-negative staphylococci.

Topics: Anti-Bacterial Agents; Cefoxitin; Drug Resistance, Bacterial; Humans; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus aureus

Penicillin binding protein 2a/2' (PBP2a/PBP2') which is encoded by the mecA gene, is responsible for the methicillin resistance in staphylococci. Detection of methicillin resistance with phenotypic methods is still a problem especially because of heterogenous expression of mecA gene. Although mecA gene determination by polymerase chain reaction is considered as the gold standard method, molecular tests are not easily applied in all routine laboratories. Thus, for the rapid and accurate diagnosis of MRSA strains, easy and practical phenotypic tests are still required. This study was conducted to compare the oxacillin (OX), cefoxitin (CFX), ceftizoxime (CZX), and moxolactam (MOX) susceptibility testing by disk diffusion method for the detection of methicillin resistance in staphylococci. A total of 247 staphylococci (125 Staphylococcus aureus and 122 coagulase-negative staphylococci; CNS) isolated from various clinical specimens (114 wound and soft tissue materials, 51 urine, 48 blood, 30 respiratory tract, and four other samples) of inpatients and outpatients, were included in this study. PBP2a latex agglutination test was used as the reference method for the recognition of methicillin resistance; four antibiotic disks tested and sensitivity, specificity, positive and negative predictive values (PPV and NPV) were determined for each of them. According to PBP2a latex agglutination test 66 (54.1%) of CNS and 53 (42.4%) of S.aureus isolates were found methicillin- resistant. OX and MOX disks detected 113 (63 CNS and 50 S.aureus) methicillin-resistant strain out of 119 PBP2a positive isolates, where CFX and CZX disks detected 110 (60 CNS and 50 S.aureus) of them. Among 128 PBP2a negative isolates, 123 (52 CNS and 71 S.aureus) were detected as susceptible with OX, 127 (55 CNS and 72 S.aureus) with CFX and CZX, 126 (54 CNS and 72 S.aureus) with MOX. According to these results, the sensitivities and specificities of OX, CFX, CZX, and MOX disks were; 95.4% and 92.8%, 90.9% and 98.2%, 90.9% and 98.2%, 95.4% and 96.4%, respectively for CNS and 94.3% and 98.6%, 94.3% and 100%, 94.3% and 100%, 94.3% and 100%, respectively for S.aureus. The difference between sensitivities and specificities of tested antibiotic disks were not found statistically significant. In conclusion, due to the problems in detection of methicillin resistance with phenotypic methods, the use of different mecA gene-inducing antibiotic disks at the same time, and utilization of molecular methods as

Topics: Anti-Bacterial Agents; Cefoxitin; Ceftizoxime; Disk Diffusion Antimicrobial Tests; Humans; Latex Fixation Tests; Methicillin; Moxalactam; Oxacillin; Penicillin-Binding Proteins; Predictive Value of Tests; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) is responsible for nosocomial and community-acquired infections. Hence, rapid and accurate laboratory diagnosis of MRSA is a vital constituent of control measures. The present study evaluated five different methods for the identification of MRSA. A total of 207 S. aureus clinical isolates that consisted of 89 MRSA and 118 methicillin-susceptible S. aureus (MSSA) strains confirmed by PCR were tested. MRSA strains were evaluated by five different methods: chromogenic MRSA agar (CMRSA), oxacillin resistance screening agar base (ORSAB), mannitol salt oxacillin agar (MSO), mannitol salt cefoxitin agar with two different concentrations of cefoxitin [4 microg/ml (MSC-4) and 6 microg/ml (MSC-6)]. The results of the different methods were compared to mecA PCR as the gold standard. MSC-6 showed only six false-positive MRSA in comparison with PCR. The sensitivities and specificities of MSC-6, MSC-4, MSO-4, ORSAB, and CMRSA were as follows: 98.9/94.9%, 100/83.1%, 89.9/87.3%, 97.8/96.6%, and 95.5/94.9%, respectively. In comparison with PCR, it was found that both MSC-6 and ORSAB were relatively the least expensive screening tests ($0.70 and $1.00, respectively). In conclusion, all methods were comparable, but MSC-6 was the least expensive medium for MRSA screening.

Topics: Agar; Anti-Bacterial Agents; Cefoxitin; Culture Media; Humans; Methicillin; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) are commonly associated with nosocomial infections and are usually resistant to many antibiotics. This study describes the prevalence of MRSA strains and their antibiogram in a tertiary care hospital in Central India. The detection of MRSA was done by a cefoxitin (30 microg) disc diffusion test. Antibiotic sensitivity tests were done as per the Clinical and Laboratory Standards Institute guidelines 2006. Of the 280 S. aureus strains studied: 145 (51.8%) strains were MRSA; 51 (35.2%) MRSA strains were inducible clindamycin resistant; and all (100%) MRSA strains were resistant to penicillin and sensitive to vancomycin and linezolid. In order to detect the MRSA strains, cefoxitin disc diffusion tests should be used routinely in any microbiology laboratory to enable prompt treatment for the patient.

Topics: Acetamides; Animals; Anti-Bacterial Agents; Cefoxitin; Drug Resistance, Multiple, Bacterial; Humans; Incidence; India; Inhibitory Concentration 50; Linezolid; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxazolidinones; Prevalence; Staphylococcal Infections; Vancomycin

The aim of the present study was to compare the performance of the new VITEK2 AST-P551 card with the cefoxitin disk diffusion method for the daily detection of methicillin resistance with a high number of Staphylococcus aureus clinical isolates. Detection of the PBP2a protein or mecA gene was performed for each discordant case. Seventy (3.3%) isolates out of 2,107 clinical strains showed discordant results, two very major errors, four major errors and 64 minor errors. Fifty-nine (84%) discordant results were resolved, with a final overall agreement of 99.5%. Eleven (0.5%) strains remained discordant (minor error [mE]). Four of 370 MRSA strains were misclassified as susceptible in daily practice by the cefoxitin disk diffusion method. All of these strains were resistant to aminoglycosides and/or fluoroquinolones. The VITEK2 system is highly reliable for methicillin resistance detection at the routine level. Oxacillin-susceptible classified clinical strains with associated resistance patterns required attention.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Diagnostic Errors; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Sensitivity and Specificity; Staphylococcal Infections

Oxacillin is the main drug used for the treatment of Staphylococcus aureus infections. However, resistance of S. aureus to oxacillin has become a major problem over recent decades. The aim of this study was to determine oxacillin resistance in S. aureus isolates obtained from the University Hospital of the Botucatu Medical School, Universidade Estadual Paulista, Brazil.. A total of 102 isolates collected between 2002 and 2006 were analyzed by detection of the mecA gene, cefoxitin and oxacillin disk diffusion methods, screening test on Mueller-Hinton agar and E-test.. Forty-six (45.1%) isolates were mecA positive. The oxacillin disk diffusion method showed 86.9% sensitivity and 91.1% specificity. The screening method and cefoxitin disk diffusion presented a similar sensitivity (91.3%) and the same specificity. The E-test showed 97.8% sensitivity and the same specificity as observed for the other methods.. The E-test yielded the best results compared to the other methods.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Brazil; Cefoxitin; Drug Resistance, Bacterial; Hospitals, University; Humans; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus aureus

This study focused on the correlation between geno- and phenotypic tests in the correct assessment of mecA-mediated methicillin resistance among coagulase-negative staphylococci (CoNS) and the further characterization of mecA-positive isolates.. A total of 121 CoNS from cases of bovine mastitis were investigated for oxacillin susceptibility by disc diffusion and broth microdilution. Isolates classified as methicillin resistant by either method were tested by PCR for the mecA gene and the SCCmec type. The cefoxitin disc test was also applied. PFGE served to determine the genetic relationships of the resistant isolates.. Sixteen isolates were classified as methicillin resistant and 96 isolates as methicillin susceptible by both methods. The mecA gene was identified in 15 of the 16 resistant isolates. Nine mecA-negative isolates showed oxacillin MICs of 0.5 or 1 mg/L, oxacillin zone sizes of 18-23 mm and were classified as methicillin susceptible in the cefoxitin disc test. SCCmec cassettes of types V (five Staphylococcus haemolyticus), III (one Staphylococcus saprophyticus), IV (five Staphylococcus epidermidis, one Staphylococcus capitis) and IV with an additional ccrA4/B4 gene (two S. epidermidis) were seen, while one S. epidermidis carried a non-typeable SCCmec element (mec complex B + no ccr gene complex detected). All isolates with SCCmec type IV or non-typeable cassettes exhibited low oxacillin MICs of 1-4 mg/L, whereas isolates with type III or V cassettes had MICs of >or=16 mg/L.. CoNS with oxacillin MICs of 0.5 and 1 mg/L should be confirmed for the presence of mecA before reporting them as methicillin resistant.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Bacterial Typing Techniques; Cattle; Cefoxitin; Coagulase; DNA Fingerprinting; DNA, Bacterial; Electrophoresis, Gel, Pulsed-Field; Female; Mastitis, Bovine; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus

A cefoxitin-susceptible Staphylococcus aureus strain was identified by the Cepheid GeneXpert as methicillin-resistant S. aureus (MRSA). This strain was highly unstable and rapidly lost SCCmec upon subculturing in vitro, indicating that unstable MRSA is best detected by gene amplification-based methods.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Bacteriological Techniques; Cefoxitin; DNA Fingerprinting; DNA, Bacterial; Electrophoresis, Gel, Pulsed-Field; Female; Genomic Instability; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Penicillin-Binding Proteins; Staphylococcal Infections

To evaluate methicillin-resistant S. aureus (MRSA) detection methods, we compared (a) mannitol salt agar with cefoxitin (MSA-FX), (b) MRSASelect agar (Bio-Rad), (c) MRSA ID (bioMerieuex), and (d) CHROMagar MRSA (BD Diagnostics) as selective media for culturing nasal swab specimens collected from intensive care unit (ICU) patients and healthcare personnel. A total of 99 (17.1%) cases of MRSA were recovered from 578 specimens. Four (5.5%) cases were identified from healthcare personnel and 95 (18.8%) were from ICU patients. The sensitivity of MSA-FX, MRSASelect, MRSA ID, and CHROMagar MRSA was 83.8, 87.9, 80.8, and 84.8% after 18 hr; 92.9, 94.9, 90.9, and 91.9% after 24 hr; and 96.0, 100, 99.0, and 99.0% after 48 hr, respectively. The specificity of MSA-FX, MRSASelect, MRSA ID, and CHROMagar MRSA was 97.7, 99.0, 98.7. and 99.8% after 18 hr; 97.1, 98.5, 98.1, and 99.5% after 24 hr; and 95.2, 97.7, 97.9, and 99.0% after 48 hr, respectively. In conclusion, all four media showed good results after the 24 hr readings, but MRSA ID and CHROMagar MRSA media required readings at 48 hr due to increased sensitivity at this time point.

Topics: Agar; Anti-Bacterial Agents; Bacterial Proteins; Blotting, Western; Cefoxitin; Chromogenic Compounds; Health Personnel; Humans; Intensive Care Units; Mannitol; Methicillin-Resistant Staphylococcus aureus; Nasal Mucosa; Penicillin-Binding Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sensitivity and Specificity; Staphylococcal Infections

Methicillin-Resistant Staphylococcus aureus (MRSA) is one of the most common and important causes of nosocomial infections. Rapid detection of this pathogen is important for conducting good and swift infection control. This prospective study evaluates two chromogenic media for the detection of MRSA. New colony characteristics were noticed during this evaluation: (i) a yellow/golden colouration on a pipette after streaking the colonies of the chromogenic culture could eventually be used as a supplementary identification test to identify the MRSA strains, and (ii) some MRSA strains do not metabolise the chromogens and therefore are not coloured on chromogenic agars. However, they have a typical yellow/golden colony aspect usually observed amongst S. aureus.

Topics: Bacterial Typing Techniques; Cefoxitin; Chromogenic Compounds; Cross Infection; Culture Media; Humans; Methicillin-Resistant Staphylococcus aureus; Phenotype; Predictive Value of Tests; Prospective Studies; Staphylococcal Infections

Five new steroids, norselic acids A-E (1-5), were isolated from the sponge Crella sp. collected in Antarctica. The planar structures of the norselic acids were established by extensive NMR spectroscopy and mass spectrometry studies, and the configuration of norselic acid A (1) was elucidated by X-ray crystallography. Norselic acid A displays antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive S. aureus (MSSA), vancomycin-resistant Enterococcus faecium (VRE), and Candida albicans and reduces consumption of food pellets by sympatric mesograzers. Compounds 1-5 are also active against the Leishmania parasite at low micromolar levels.

Topics: Animals; Antarctic Regions; Anti-Infective Agents; Candida albicans; Enterococcus faecium; Leishmania; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Molecular Structure; Porifera; Staphylococcal Infections; Steroids; Vancomycin Resistance

The recommended breakpoints for the cefoxitin disk diffusion test for Staphylococcus aureus were recently modified. In this large-sample study, cefoxitin sensitivity and specificity compared to those of oxacillin were 97.3% and 100%, respectively. This study validated the new cefoxitin breakpoints for the detection of mecA-mediated resistance in S. aureus.

Topics: Anti-Bacterial Agents; Cefoxitin; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Sensitivity and Specificity; Staphylococcal Infections

Clinical and Laboratory Standards Institute interpretive breakpoints for in vitro susceptibility tests that predict mecA-mediated oxacillin resistance in Staphylococcus pseudintermedius isolates from animals have been changed twice in the past decade. Moreover, there are no counterpart recommendations for human isolates of S. pseudintermedius. Individual medical and veterinary laboratories variably use interpretive breakpoints identical to those recommended for use with Staphylococcus aureus or identical to those recommended for use with coagulase-negative staphylococci. The purpose of the current study was to examine correlations between oxacillin disk diffusion, oxacillin gradient diffusion, oxacillin microbroth dilution, and cefoxitin disk diffusion tests used to predict mecA-mediated resistance in S. pseudintermedius and to retrospectively estimate, from disk diffusion zone diameter measurements, the prevalence and rate of increase of oxacillin resistance among canine S. pseudintermedius isolates submitted to a veterinary teaching hospital laboratory. Oxacillin disk diffusion zone diameters of or=0.5 microg/ml were highly correlated with detection of mecA in canine S. pseudintermedius isolates by polymerase chain reaction. MecA-mediated resistance among S. pseudintermedius isolates from dogs increased from less than 5% in 2001 to near 30% in 2007. More than 90% of the methicillin-resistant S. pseudintermedius isolates in 2006 and 2007 were also resistant to representatives of >or=4 additional antimicrobial drug classes. Cefoxitin disk diffusion with the resistance breakpoint set at

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Dog Diseases; Dogs; Drug Resistance, Bacterial; Oxacillin; Staphylococcal Infections; Staphylococcus; Time Factors

We describe a calorimetric assay for the detection of methicillin-resistant Staphylococcus aureus (MRSA) within 5 h. Microbial heat was calculated in culture with and without cefoxitin. Among 30 genetically distinct clinical isolates, 19/20 MRSA (95%) and 10/10 methicillin-susceptible Staphylococcus aureus (100%) were correctly identified. Microcalorimetry may be useful for rapid MRSA screening.

Topics: Anti-Bacterial Agents; Calorimetry; Cefoxitin; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus aureus; Time Factors

To type the staphylococcal cassette chromosome (SCC) in coagulase-negative staphylococci (CoNS) from animal sources.. A total of 92 CoNS isolates recovered from farm animals was analysed. The top three staphylococcal species were Staphylococcus lentus (34), S. sciuri (31), and S. xylosus (13). The presence of the cassette chromosome recombinase (ccr) genes ccrA1, ccrB1, ccrA2, ccrB2, ccrA3, ccrB3 and ccrC, the mec regulatory genes mecI and mecR1, and Tn554 was used to differentiate the SCC. A total of 60 of the 92 isolates were methicillin resistant. Among the 60 methicillin-resistant Staphylococcus spp. isolates, SCCmec (mecA-carrying SCC) types I, III, IV and V were identified in 24 isolates based on the combinations of the ccr genes and the mec regulatory genes, with type III being predominant. The single S. epidermidis carried SCCmec type IV. SCC type III was also identified in two of 32 methicillin-susceptible isolates. Identical SCCmec types were present in different species of CoNS. Pulsed-field gel electrophoresis (PFGE) generated 64 patterns out of 81 PFGE typeable isolates. Indistinguishable clones were detected in animals from different farms.. Heterogeneous SCC existed in CoNS of diverse genetic background. Both clonal transmission of methicillin-resistant CoNS and horizontal transfer of SCCmec occurred in the animal production environment.. This study adds to our knowledge of SCCmec type and the diversity of SCC in CoNS.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Birds; Cefoxitin; Chromosomes, Bacterial; Coagulase; DNA, Bacterial; Electrophoresis, Gel, Pulsed-Field; Genetic Variation; Mammals; Methicillin Resistance; Microbial Sensitivity Tests; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus

Methicillin-resistant Staphylococcus aureus (MRSA) arises when methicillin-susceptible S. aureus (MSSA) acquires the staphylococcal cassette chromosome mec (SCCmec). Most pvl-positive MRSA in Taiwan belong to ST59 lineage and carry SCCmec V. The genetic profiles of 51 MSSA were compared with those of 80 MRSA from the same hospitals. Nine pvl-positive MSSA (oxacillin MIC < or = 2 microg/mL) shared >80% similarity in pulsed field gel electrophoresis pattern with 17 pvl-positive SCCmec V MRSA. Further investigation found that 5 of these 9 isolates were MRSA by cefoxitin and carried SCCmec V. All 26 pvl-positive isolates had very similar genetic profile (ST59, protein A clonal complex [spa-CC] c2:441/437, and agr group I). The success of the ST59:SCCmec V MRSA may be due in part to its heterogeneous and borderline resistance to methicillin, which may be missed by testing only oxacillin, with subsequent exposure to beta-lactams causing the emergence of more resistant subpopulations.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Bacterial Toxins; Bacterial Typing Techniques; Cefoxitin; Cluster Analysis; DNA Fingerprinting; DNA, Bacterial; Electrophoresis, Gel, Pulsed-Field; Exotoxins; Genes, Bacterial; Genotype; Hospitals; Humans; Leukocidins; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Staphylococcal Infections; Staphylococcus aureus; Taiwan

The heterogeneous expression of methicillin resistance in Staphylococcus aureus affects the efficiency of tests available to detect it. Not all laboratories have access to accurate molecular tests used for this purpose. This study compares the performances of four phenotypic tests used to detect methicillin resistant S. aureus (MRSA) with the mecA gene polymerase chain reaction. Two hundred thirty-seven S. aureus isolates were isolated from different patients visiting Sir Sundar Lal Hospital, Banaras Hindu University, Varanasi, India and subjected to cefoxitin and oxacillin disc diffusion tests, oxacillin minimum inhibitory concentration (MIC) test, and oxacillin screen agar test. The tests showed the following sensitivities and specificities, respectively: cefoxitin disc diffusion (98.5% and 100%), oxacillin disc diffusion (77.3% and 84.6%), oxacillin MIC (89.4% and 87.2%), and oxacillin screen agar (87.9% and 94.9%). The cefoxitin disc diffusion test can be the best method for routine detection of MRSA when molecular techniques are not available. We recommend the Clinical Laboratory Standards Institute (CLSI) cut-off point for determining cefoxitin resistance be reexamined to see if it should be revised from < or = 19 mm to < or = 20 mm.

Topics: Bacterial Proteins; Cefoxitin; Developing Countries; Disk Diffusion Antimicrobial Tests; Humans; Methicillin-Resistant Staphylococcus aureus; Oxacillin; Penicillin-Binding Proteins; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections

A 2-year-old dog was evaluated because of complications that developed following tibial plateau leveling osteotomy. Infection of the surgical site developed following removal of the failed implant.. The dog was lame with evidence of a deep surgical site infection, and Staphylococcus pseudintermedius was isolated from the surgical site. Results of in vitro testing indicated that the isolate was resistant to multiple antimicrobials but susceptible to cefoxitin. Subsequent testing confirmed that the isolate was methicillin-resistant S pseudintermedius and was in fact resistant to cefoxitin.. On the basis of results of follow-up testing, doxycycline was administered before and after surgery to remove the surgical implant. The dog recovered without further complications.. Findings suggested that certain strains of methicillin-resistant S pseudintermedius, which appears to be an emerging pathogen in dogs, may be falsely identified as methicillin susceptible on the basis of results of testing for cefoxitin susceptibility because cefoxitin may not induce the mecA gene as reliably in S pseudintermedius as it does in Staphylococcus aureus. Isolates of S pseudintermedius should be considered to likely be methicillin resistant when multidrug resistance is identified, even if susceptibility to some beta-lactam antimicrobials is reported.

Topics: Animals; Anti-Bacterial Agents; Bone Plates; Cefoxitin; Dog Diseases; Dogs; Doxycycline; Male; Methicillin Resistance; Staphylococcal Infections; Staphylococcus; Surgical Wound Infection

Staphylococcus saprophyticus is a uropathogenic bacterium that causes acute uncomplicated urinary tract infections, particularly in female outpatients. We investigated the dissemination and antimicrobial susceptibilities of 101 S. saprophyticus isolates from the genitourinary tracts of patients in Japan. Eight of these isolates were mecA positive and showed beta-lactam resistance. Pulsed-field gel electrophoresis showed that only some isolates were isogenic, indicating that the mecA gene was apparently acquired independently by mecA-positive isolates through staphylococcal cassette chromosome mec (SCCmec). Type determination of SCCmec by multiplex PCR showed a nontypeable element in the eight mecA-positive isolates. Sequence analysis of the entire SCCmec element from a prototype S. saprophyticus strain revealed that it was nontypeable with the current SCCmec classification due to the novel composition of the class A mec gene complex (IS431-mecA-mecR1-mecI genes) and the ccrA1/ccrB3 gene complex. Intriguingly, the attachment sites of SCCmec are similar to those of type I SCCmec in S. aureus NCTC 10442. Furthermore, the genes around the mec gene complex are similar to those of type II/III SCCmec in S. aureus, while those around the ccr gene complex are similar to those of SCC15305RM found in S. saprophyticus ATCC 15305. In comparison with known SCCmec elements, this S. saprophyticus SCCmec is a novel type.

Topics: Bacterial Proteins; Chromosomes, Bacterial; Electrophoresis, Gel, Pulsed-Field; Methicillin Resistance; Molecular Sequence Data; Polymerase Chain Reaction; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus; Urinary Tract Infections

Recent cases of infections caused by community-acquired methicillin-resistant Staphylococcus aureus (MRSA) (CA-MRSA) strains in healthy individuals have raised concerns worldwide. CA-MRSA strains differ from hospital-acquired MRSAs by virtue of their genomic background and increased virulence in animal models. Here, we show that in two common CA-MRSA isolates, USA300 and MW2 (USA400), a loss of penicillin binding protein 4 (PBP4) is sufficient to cause a 16-fold reduction in oxacillin and nafcillin resistance, thus demonstrating that mecA, encoding PBP2A, is not the sole determinant of methicillin resistance in CA-MRSA. The loss of PBP4 was also found to severely affect the transcription of PBP2 in cells after challenge with oxacillin, thus leading to a significant decrease in peptidoglycan cross-linking. Autolysis, which is commonly associated with the killing mechanism of penicillin and beta-lactams, does not play a role in the reduced resistance phenotype associated with the loss of PBP4. We also showed that cefoxitin, a semisynthetic beta-lactam that binds irreversibly to PBP4, is synergistic with oxacillin in killing CA-MRSA strains, including clinical CA-MRSA isolates. Thus, PBP4 represents a major target for drug rediscovery against CA-MRSA, and a combination of cefoxitin and synthetic penicillins may be an effective therapy for CA-MRSA infections.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Base Sequence; beta-Lactam Resistance; Cefoxitin; Community-Acquired Infections; DNA Primers; DNA, Bacterial; Drug Therapy, Combination; Gene Deletion; Genes, Bacterial; Genetic Complementation Test; Humans; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Mutation; Penicillin-Binding Proteins; Penicillins; Phenotype; Staphylococcal Infections

Detection of methicillin resistance in Staphylococcus aureus is a challenge, especially low-level resistance, which is often misdiagnosed. The aim of this study was to compare the diagnostic accuracies of the automated Vitek 2 system and disk diffusion tests, using cefoxitin and moxalactam, for the detection of methicillin resistance in S. aureus strains. Four sets of genotypically diverse isolates were selected from a national reference collection, including mecA-negative S. aureus isolates (n = 56), hospital-acquired (n = 88) and community-acquired (n = 40) S. aureus isolates, and heterogeneous methicillin-resistant S. aureus isolates (n = 29). Oxacillin susceptibility was tested by the Vitek 2 system with the AST P549 card and by disk diffusion methods using 10, 30, and 60 microg cefoxitin and 30 microg moxalactam. Oxacillin resistance was confirmed by PCR for the mecA gene. The overall sensitivities for oxacillin resistance detection were 97.5% for the Vitek 2 automated system, 98.7% for 60-microg cefoxitin and moxalactam disk diffusion, and 99.6% for 10- and 30-microg cefoxitin disks, respectively. Methicillin-susceptible S. aureus isolates were correctly reported as susceptible by all methods. The median times for methicillin testing were 7 h for the Vitek 2 system versus 24 h for disk diffusion methods. In conclusion, the cefoxitin and moxalactam disk diffusion methods and the Vitek 2 automated system are highly accurate methods for methicillin resistance detection, including a range of representative Belgian methicillin-resistant S. aureus strains and unusual strains exhibiting cryptic or low-level oxacillin resistance.

Topics: Anti-Bacterial Agents; Automation; Bacterial Proteins; Belgium; Cefoxitin; DNA, Bacterial; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Moxalactam; Oxacillin; Penicillin-Binding Proteins; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus aureus; Time Factors

In this study we evaluated the performance of the oxacillin agar screen test, and agar dilution tests using cefoxitin and oxacillin antimicrobials, to detect meticillin resistance in Staphylococcus aureus isolates. The presence of the mecA gene, detected by PCR, was used as the standard to which agar screen and agar dilution tests were compared. The best performance was obtained using the agar dilution test (99.4 % accuracy) with breakpoints of 4 mug ml(-1) for oxacillin and 8 mug ml(-1) for cefoxitin, and using the oxacillin agar screen test. Also, a strong correlation between MIC values of cefoxitin and oxacillin permits the use of either drug for detection of meticillin resistance.

Topics: Agar; Cefoxitin; Humans; Inpatients; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus aureus

A total of 276 blood culture bottles with Staphylococcus aureus were tested by direct cefoxitin disk diffusion testing; 105 (38.1%) had zone sizes of /=21 mm (all 137 had MSSA). Detection of MRSA/MSSA in blood cultures could be reported 10 to 24 h earlier for 88% of cultures with total accuracy.

Topics: Aged; Aged, 80 and over; Anti-Bacterial Agents; Bacteremia; Blood; Cefoxitin; Diffusion; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus aureus

Accurate and rapid detection of methicillin-resistant Staphylococcus aureus is very important in a clinical laboratory setting to avoid treatment failure. Conventional methods were compared against the gold standard polymerase chain reaction (PCR) technique to determine the best combination of the routine procedures.. Methicillin resistance was investigated in 416 clinical Staphylococcus aureus isolates by PCR, oxacillin agar screening (OAS), oxacillin disk diffusion (ODD) and cefoxitin disk diffusion (CDD) methods.. Two hundred and ten (51%) out of 416 S. aureus strains were found to be mecA-positive by PCR. Sensitivity and specificity of the ODD, CDD and OAS methods were detected as follows: 100% and 89%, 99.50% and 100%, and 99.50% and 100%, respectively.. Combining the ODD and CDD methods could be a good choice for detecting methicillin resistance in S. aureus strains where mecA PCR cannot be performed.

Topics: Cefoxitin; Disk Diffusion Antimicrobial Tests; Humans; Methicillin-Resistant Staphylococcus aureus; Oxacillin; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections

In this study, the use of isothermal microcalorimetry (IMC) for differentiation between methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) and MIC determination was evaluated. It was possible to differentiate between MRSA and MSSA within 4 h, whereas the standard method required 24 h. The MICs of cefoxitin were successfully determined for MRSA and MSSA by using IMC.

Topics: Anti-Bacterial Agents; Calorimetry; Cefoxitin; Hot Temperature; Humans; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus aureus; Time Factors

Mannitol salt agar (MSA), CHROMagar Staph aureus (CSA) and CHROMagar MRSA (CSA-MRSA) were evaluated with nasal surveillance specimens for their ability to detect Staphylococcus aureus and meticillin-resistant S. aureus (MRSA). CSA was found to be more sensitive than MSA in detecting S. aureus (98 versus 84.3 %; P=0.03). CSA and CSA-MRSA were equivalent in the ability to detect MRSA at 24 h (89.7 versus 87.2 %) and at 48 h (94.9 versus 94.9 %). When combined with Staphaurex slide confirmation testing, both CSA and CSA-MRSA were highly specific (100 %) media for detecting MRSA from nasal swab specimens.

Topics: Agar; Anti-Bacterial Agents; Cefoxitin; Chromogenic Compounds; Culture Media; Humans; Mannitol; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Nasal Mucosa; Species Specificity; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus

Members of the genus Staphylococcus are among the most important human pathogens, and strains demonstrating resistance to methicillin are an increasing problem worldwide, both within and outside of hospital environments. The objective of this study was to evaluate the use of variations of agar screening tests with cefoxitin and oxacillin to detect methicillin resistance in staphylococcal isolates. The agar screening test with cefoxitin (4 microg/ml) showed 99.4% accuracy for detecting both S. aureus and coagulase-negative staphylococci. The performance of the agar screening test with cefoxitin (4 microg/ml) either equaled or was superior to the other agar screening test variations evaluated and can be used to characterize the presence of the mecA gene among staphylococcal species.

Topics: Agar; Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus

Methicillin-resistant S. epidermidis are recognized as one of the most important nosocomial infections. Because of the different expression level of mecA gene which is under regulatory genes control, detection of methicillin resistance by phenotypic methods may leads to false negative or false positive results. The aim of this study was to estimate effectiveness of MRSE strains identification using oxacillin (1 microg) and cefoxitin (30 microg) disk-diffusion method in comparison with PCR, considered as a "gold standard". The analysis of 120 strains isolated from clinical materials of patients of the University Hospital at the L. Rydygier Collegium Medicum in Bydgoszcz, University of Nicolaus Copernicus in Toruń indicated high degree of correlation between phenotypic methods with taken disks. Results consistency of detecting methicillin resistance between oxacillin disk diffusion method and PCR concerned 95% strains. In case of cefoxitin 4,2% S. epidermidis strains detected phenotypically as MSSE were mecA-positive. Our results show that disk-diffusion method with disks mentioned above is characterized by comparable specificity and sensitivity amounted 90,8% and 100% for oxacillin and 92,3% and 100% for cefoxitin respectively.

Topics: Bacterial Typing Techniques; Cefoxitin; Disk Diffusion Antimicrobial Tests; False Positive Reactions; Hospitalization; Humans; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Polymerase Chain Reaction; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus epidermidis

In the present study, several conventional methods to detect methicillin-resistant Staphylococcus aureus (MRSA) were compared with polymerase chain reaction (PCR) detection of mecA gene-positive isolates. Cefoxitin E-test was also evaluated as a possible phenotypic method of MRSA detection. Oxacillin agar screen and PBP2' latex agglutination methods were found to be more sensitive than oxacillin and cefoxitin disk-diffusion methods. Cefoxitin disk diffusion was found to be the most specific. A combination of oxacillin agar screening with cefoxitin disk diffusion, or oxacillin disk diffusion with PBP2', improved sensitivity and specificity. Cefoxitin E-test with the current break points had low sensitivity and specificity (33.3% and 75%, respectively) for the detection of MRSA. However, changing the break points to or= 6 microg/ml for sensitive and resistant, respectively, greatly improved both. Changing the 30-microg cefoxitin disk-diffusion break points to

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; DNA, Bacterial; Humans; Latex Fixation Tests; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Penicillin-Binding Proteins; Phenotype; Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus aureus

Cinical and Laboratory Standards Institute (CLSI) recommends the use of cefoxitin disks instead of long-used oxacillin disks for screening methicillin-resistant isolates of staphylococci. The frequency of discrepant results and accuracy of the tests were evaluated by detecting mecA gene.. A total of 3,123 Stapylococci isolates from patients in Severance Hospital were tested during September 2005 to August 2006 by the CLSI-recommended test using both cefoxitin and oxacillin disks. The mecA gene was detected by PCR and the oxacillin minimum inhibitory concentration (MIC) was determined by using agar dilution method for the isolates with discrepant tests.. Among 1,915 S. aureus islolates tested, one isolate was resistant to oxacillin disk but susceptible to cefoxitin disk; the isolate did not have mecA gene. Another isolate susceptible to oxacillin but resistant to cefoxitin had mecA gene. Among 1,208 coagulase-negative staphylococcal isolates, 15 isolates were resistant to oxacillin disk but susceptible to cefoxitin disk; the isolates did not have mecA genes. Two isolates susceptible to oxacillin disk but resistant to cefoxitin disk had mecA genes. Among the 16 Staphylococcus isolates that did not have mecA gene, 15 isolates had the oxacillin MICs of

Topics: Anti-Bacterial Agents; Bacterial Proteins; Cefoxitin; Disk Diffusion Antimicrobial Tests; Humans; Methicillin; Methicillin Resistance; Oxacillin; Penicillin-Binding Proteins; Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus aureus

The aim of this study was to evaluate the accuracy of cefoxitin disc diffusion as a prediction of oxacillin resistance in coagulase-negative staphylococci (CoNS), and also to compare genotypic and phenotypic methods for detecting this resistance property. A total of 151 clinical CoNS isolates were tested by PCR for the presence of the mecA gene (gold standard method). The isolate susceptibilities were determined by the disc diffusion method with oxacillin (1 microg) and cefoxitin (30 microg) and by the agar dilution method for cefoxitin and oxacillin. Although none of the techniques showed 100% sensitivity and 100% specificity, the cefoxitin disc diffusion and oxacillin agar dilution were the best methods for detecting resistance to oxacillin among CoNS as these methods produced the best negative and positive predictive values. A combination of methods can be used routinely to identify resistance to oxacillin in CoNS.

Topics: Anti-Bacterial Agents; Cefoxitin; Coagulase; Drug Resistance, Bacterial; Genes, Bacterial; Humans; Microbial Sensitivity Tests; Oxacillin; Predictive Value of Tests; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus

Ingested foreign bodies rarely cause gastrointestinal perforation, because the majority are passed out uneventfully in the feces. However, long, sharp, slender, hard, indigestible objects such as toothpicks are dangerous and may lead to potentially life-threatening complications. We report a case of duodenal perforation caused by a toothpick and complicated by liver abscess and methicillin-resistant Staphylococcus aureus sepsis. Although laparotomy was not performed because of the patient's refusal to undergo surgery, the liver abscess and sepsis were controlled successfully with antibiotics. We also conducted a literature search for reports on injuries caused by ingested toothpicks.

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Bacteremia; Cefoxitin; Duodenum; Follow-Up Studies; Foreign-Body Migration; Humans; Intestinal Perforation; Liver; Liver Abscess; Male; Methicillin Resistance; Metronidazole; Middle Aged; Staphylococcal Infections; Tomography, X-Ray Computed; Ultrasonography; Vancomycin

We compared MRSA Select to mannitol-salt agar with 8 microg/ml cefoxitin for the detection of methicillin-resistant Staphylococcus aureus (MRSA) from 6,199 clinical samples submitted for MRSA screening. The sensitivities and specificities of MRSA Select and mannitol-salt agar with cefoxitin were 98% and 92% versus 90% and 78%, respectively (P<0.0001). Most (96%) MRSA were detected after overnight incubation using MRSA Select.

Topics: Anti-Bacterial Agents; Bacteriological Techniques; Cefoxitin; Culture Media; Humans; Methicillin Resistance; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus aureus

Topics: Anti-Bacterial Agents; Brazil; Cefoxitin; Coagulase; Humans; Microbial Sensitivity Tests; Oxacillin; Penicillin Resistance; Staphylococcal Infections; Staphylococcus

Coagulase-negative staphylococci (CoNS) are a significant cause of nosocomial bacteraemia and their susceptibility to beta-lactamase-stabile penicillins is unpredictable. To ensure appropriate antibiotic therapy reliable methods for detection of methicillin resistance (MR) are needed. The objectives of this study were to determine the frequency of MR in a set of CoNS from cases of monomicrobial bacteraemia and to evaluate two phenotypic assays for detection of MR, the 10 microg cefoxitin disk test on Iso-Sensitest agar using a semiconfluent inoculum and the oxacillin Etest. MR was determined by a commercial genomic mecA assay. Of 110 CoNS, 75 were mecA positive and 35 mecA negative. Using interpretive zone diameters R < 22 mm and S > or = 27 mm, the cefoxitin disk test had a sensitivity and specificity of 100%. A correct prediction was obtained for 86 isolates, while 23 were indeterminate (> or = 22 mm; <27 mm). Using CLSI's guidelines, sensitivity and specificity of the oxacillin Etest were 100% and 80%, respectively. A correct prediction was obtained for 102 isolates, while 7 mecA negative isolates were classified as resistant. Thus, the cefoxitin disk test and the oxacillin Etest performed with high accuracy and both seem to be suitable for routine use.

Topics: Anti-Bacterial Agents; Bacteremia; Bacterial Proteins; Cefoxitin; Coagulase; Humans; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Penicillin-Binding Proteins; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus

The emergence of heterogeneous populations of methicillin-resistant Staphylococcus aureus (MRSA) causes major problems in routine screening for MRSA. In heterogeneous MRSA populations, a proportion of bacterial cells show low-level resistance to oxacillin, with minimal inhibitory concentrations (MICs) of oxacillin ranging between 1 and 100 mg/l, while in homogeneous MRSA populations, the MIC of oxacillin for all cells is >100 mg/l. Routine oxacillin disk diffusion tests often fail to detect heterogeneous MRSA populations. In the present study, a recently proposed disk diffusion method that employs a cephamycin antibiotic (cefoxitin 30 microg; BD Sensi-disc, Becton Dickinson, Germany) was evaluated using 155 clinical isolates of S. aureus (73 mecA positive and 82 mecA negative). The results were compared with those of other MRSA screening techniques: a disk diffusion test with oxacillin 1 microg and cefoxitin 30 microg (BD Sensi-disc; Becton Dickinson), an MRSA latex agglutination test (Denka Seiken, Japan), and an oxacillin screen agar test (6 microg/ml; Becton Dickinson). Detection of the mecA gene by polymerase chain reaction was considered the gold standard. The performances of the different methods were determined and compared. The results showed that the cefoxitin disk diffusion test is preferable to the oxacillin disk diffusion method for routine screening to detect MRSA.

Topics: Agar; Anti-Bacterial Agents; Cefoxitin; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Oxacillin; Staphylococcal Infections; Staphylococcus aureus

Two oxacillin disk methods were compared with a cefoxitin disk diffusion test for detection of methicillin-resistant Staphylococcus aureus (MRSA), with PCR for mecA as the reference method. When tested with 115 MRSA and 350 methicillin-susceptible S. aureus isolates, the cefoxitin disk test (specificity 100%, sensitivity 96.5%) was superior to the oxacillin disk methods (specificity 99.1%, sensitivity 90.4%). Testing with both oxacillin and cefoxitin disks would give better sensitivity (100%) than the cefoxitin test alone, but at the expense of specificity (99.1%). The cefoxitin disk test required no special test conditions and would improve the reliability of routine tests for detection of MRSA.

Topics: Anti-Bacterial Agents; Cefoxitin; Humans; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus aureus

Very-low-level methicillin-resistant Staphylococcus aureus (MRSA), or class 1 MRSA, is often misdiagnosed as methicillin-susceptible S. aureus (MSSA). We evaluated the performances of three methods for detection of low-level methicillin resistance: the disk diffusion method using the cephamycin antibiotics cefoxitin and moxalactam, the Vitek 2 system (bioMérieux), and the MRSA-screen test (Denka). Detection of the mecA gene by PCR was considered to be the "gold standard." We also determined the sensitivity of the oxacillin disk diffusion method with 5- and 1-microg disks and that of the Oxascreen agar assay with 6 mg of oxacillin liter(-1) for detection of MRSA. We compared the distributions of MICs of oxacillin and cefoxitin by the E-test (AB Biodisk), and those of moxalactam by dilutions in agar, for MRSA and MSSA isolates. The 152 clinical isolates of S. aureus studied were divided into 69 MSSA (mecA-negative) and 83 MRSA (mecA-positive) isolates, including 63 heterogeneous isolates and 26 class 1 isolates (low-level resistance). The cefoxitin and moxalactam disk diffusion tests detected 100% of all the MRSA classes: cefoxitin inhibition zone diameters were <27 mm, and moxalactam inhibition zone diameters were <24 mm. The Vitek 2 system and the MRSA-screen test detected 94 and 97.6% of all MRSA isolates, respectively. The sensitivities of the 5- and 1-microg oxacillin disks were 95.2 and 96.4%, respectively, whereas that of the Oxascreen agar screen assay was 94%. All of the tests except the 1-microg oxacillin disk test were 100% specific. For the class 1 MRSA isolates, the sensitivity of the Vitek 2 test was 92.3%, whereas those of the MRSA-screen test and the disk diffusion method with cefoxitin and moxalactam were 100%. Therefore, the cefoxitin and moxalactam disk diffusion methods were the best-performing tests for routine detection of all classes of MRSA.

Topics: Bacterial Proteins; Carrier Proteins; Cefoxitin; Gene Expression Regulation, Bacterial; Hexosyltransferases; Hospitalization; Humans; Lactams; Latex Fixation Tests; Methicillin; Methicillin Resistance; Microbial Sensitivity Tests; Moxalactam; Muramoylpentapeptide Carboxypeptidase; Oxacillin; Penicillin-Binding Proteins; Peptidyl Transferases; Staphylococcal Infections; Staphylococcus aureus

Cefoxitin, cefotetan, and cefmetazole were compared in 10-day therapy of intra-abdominal and subcutaneous infections caused by three organisms: Bacteroides fragilis and Bacteroides thetaiotaomicron combined with either Escherichia coli or Staphylococcus aureus. Intra-abdominal infection was caused by B. fragilis plus B. thetaiotaomicron plus E. coli. Therapy was initiated immediately before inoculation or was delayed for 8 h. Mortality was 14 of 30 (47%) for saline-treated mice, and all survivors developed abscesses. Immediate therapy reduced mortality and the percentage of mice with abscesses (in survivors), respectively, to 17 and 20% with cefoxitin, 0 and 13% with cefotetan, and 0 and 17% with cefmetazole, and the numbers of all bacteria were reduced by all the cephalosporins. Delayed therapy reduced mortality and abscess formation, respectively, to 20 and 8% of mice with cefoxitin, 10 and 93% with cefotetan, and 7 and 96% with cefmetazole. B. thetaiotaomicron survived in all abscesses treated with cefotetan and cefmetazole. Subcutaneous abscesses were caused by each organism alone or in combinations of one aerobe (S. aureus or E. coli) and one or two Bacteroides species. Early therapy reduced the numbers of all bacteria independent of their in vitro susceptibility. All agents reduced the number of each Bacteroides species with either E. coli or S. aureus. However, when therapy was delayed, cefotetan and cefmetazole were less effective than cefoxitin against B. thetaiotaomicron. Cefotetan was the most active agent against E. coli, and cefmetazole was the most effective against S. aureus. These data illustrate the efficacy of all tested cephalosporins in the prophylaxis of polymicrobial infections.

Topics: Abdomen; Abscess; Animals; Bacterial Infections; Bacteroides fragilis; Bacteroides Infections; Cefmetazole; Cefotetan; Cefoxitin; Disease Models, Animal; Escherichia coli; Escherichia coli Infections; Male; Mice; Microbial Sensitivity Tests; Skin Diseases, Bacterial; Staphylococcal Infections; Staphylococcal Skin Infections; Staphylococcus aureus

This report compares the in vitro activity of three cephalosporins (cephalothin, cefoxitin and ceftriaxone) against 57 Staphylococcus aureus strains isolated from cows with clinical mastitis on the basis of the minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC). The majority of the S aureus strains showed resistance to cefoxitin and ceftriaxone and sensitivity to cephalothin. The highest MICs and MBCs were found for cefoxitin and ceftriaxone. Antimicrobial tolerance (MBC/MIC greater than or equal to 32:1) was observed in relation to cephalothin and ceftriaxone. The data suggest that these cephalosporins may not be effective for the treatment of staphylococcal bovine mastitis. The precise definition of their antimicrobial efficacies requires more detailed in vitro and in vivo studies.

Topics: Animals; Cattle; Cefoxitin; Ceftriaxone; Cephalothin; Female; Mastitis, Bovine; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus aureus

Protein binding, serum kinetics and minimum inhibitory concentrations (MICs) for Staphylococcus aureus were determined for cefoxitin, cefazolin, ceftazidime and ceftriaxone in the rabbit. MICs of cefazolin and cefoxitin were also measured for Escherichia coli. Varying concentrations of the bacteria were administered intradermally to create areas of cellulitis, which were quantified as mean erythematous areas (EAs). Despite large differences in protein binding of the antibiotics (range 12-88%) and antibiotic dosing to allow serum concentrations to drop below the respective MICs, there was no statistical difference in the mean EAs of the animals after bacterial challenge. Antibiotic protein binding did not alter the course of cellulitis nor correlate with bacterial MIC in this model.

Topics: Animals; Bacterial Infections; Biological Availability; Cefazolin; Cefoxitin; Ceftazidime; Ceftriaxone; Cephalosporins; Chromatography, High Pressure Liquid; Escherichia coli Infections; Female; Kinetics; Protein Binding; Rabbits; Staphylococcal Infections

Vascular prosthetic graft infection is one of the most catastrophic problems complicating vascular surgery. The purpose of the present study was to determine the efficacy of binding an antibiotic to a vascular prosthesis via a glucosaminoglycan-keratin luminal coating (GKLC). Ten adult mongrel dogs had polytetrafluoroethylene (PTFE) grafts inserted into the right common carotid artery and PTFE grafts with GKLC bonded with cefoxitin inserted into the left common carotid artery. Before the neck incision was closed, an infusion of 1 X 10(8) Staphylococcus aureus was administered intravenously during a 15-minute period to each dog. Grafts were harvested at 10 different time periods (1, 2, 3, 5, 7, 10, 14, 18, 21, and 28 days). At the time of harvesting, cultures were taken of the lumen of each graft. Washout of antibiotic from the graft lumen was determined by measuring zones of inhibition of disks excised from the antibiotic grafts that were placed on S. aureus plates. Results demonstrated that only 1 of the 10 GKLC-cefoxitin grafts was infected compared with 10 of 10 regular PTFE grafts (p less than 0.003). Regression analysis showed antibiotic elution to occur in an exponential fashion (r = 0.9654) with no detectable antibiotic present after 10 days. GKLC with cefoxitin significantly protects the PTFE graft lumen from infection during bacteremia compared with regular PTFE. The role of antibiotic-bound grafts in relation to the use of intravenous antibiotics will need to be determined by further studies.

Topics: Animals; Bacterial Infections; Blood Vessel Prosthesis; Cefoxitin; Dogs; Glycosaminoglycans; Keratins; Polytetrafluoroethylene; Staphylococcal Infections

An experimental wound model has been used to evaluate the effectiveness of cefazolin and cefoxitin in the prevention of wound infection. Incisions were contaminated with Staph. aureus, E. coli, or a standardized fecal suspension. Regardless of the contaminant employed, the prophylactic use of either cefazolin or cefoxitin yielded lower wound bacterial concentrations and fewer infections compared with treatment with placebo. Cefazolin proved just as effective as cefoxitin in preventing infection when wounds were contaminated with Staph. aureus or E. coli. Although cefoxitin is the only cephalosporin that offers anaerobic coverage, its prophylactic administration when wounds were contaminated with a standardized fecal suspension did not significantly alter wound bacterial concentrations or infection rates compared with cefazolin. The data from our animal wound model suggest that prophylactic anaerobic coverage is not necessary.

Topics: Animals; Cefazolin; Cefoxitin; Escherichia coli Infections; Feces; Female; Mice; Mice, Inbred Strains; Premedication; Staphylococcal Infections; Surgical Wound Infection

Plasma levels of antibiotics often do not correlate well with their tissue levels. To determine optimal antibiotic coverage for prophylactic effect in vascular surgery, we studied the tissue pharmacokinetics of four cephalosporins in dogs: cefazolin, cefoxitin, cefamandole, and moxalactam for 3 hours after a single (25 mg/kg) intravenous injection. The minimal inhibitory concentration (MIC) of these antibiotics for the three most common pathogens involved in graft infections (Staphylococcus aureus, S. albus, and Escherichia coli) and their tissue concentration (TC) in the plasma, muscle, subcutaneous tissue, and aortic wall were assayed. The data are presented as TC/MIC ratio. Cefoxitin and moxalactam failed to achieve an effective therapeutic TC/MIC ratio (greater than 10) for S. aureus and S. albus in all the tissues studied whereas cefoxitin and cefamandole were above therapeutic levels. All antibiotics achieved an effective therapeutic ratio against E. coli, but cefamandole performed better (p less than 0.05) than cefoxitin; the latter reached effective levels at 3 hours. Cefamandole attained the most effective bioactive aortic tissue levels when the three most common pathogens were considered together and should therefore be considered as an antibiotic agent of choice for prophylaxis in vascular surgery.

Topics: Animals; Aorta; Bacterial Infections; Cefamandole; Cefazolin; Cefoxitin; Cephalosporins; Dogs; Escherichia coli Infections; Kinetics; Moxalactam; Muscles; Staphylococcal Infections; Time Factors; Tissue Distribution; Vascular Surgical Procedures

The possibility of reducing the incidence of postoperative recurrences of pilonidal fistulas by using preoperative doses of Cephoxitine and primary surgical closure is described.

Topics: Cefoxitin; Escherichia coli Infections; Humans; Pilonidal Sinus; Preoperative Care; Staphylococcal Infections; Streptococcal Infections

Our clinical experience with new antibiotics giving special consideration to the individual cephalosporin groups is discussed. Although newer cephalosporins from cefamandol and cefoxitin to cefotiam and cefoperazon already showed increased effectiveness (for example, cefoxitin in bacteroides infection) in comparison to older ones, the real breakthrough regarding enterobacteriaceae was only made with cephalosporins of the cefotaxime group. This group's main indication is non-specific initial therapy of severe nosocomial infections, especially processes in which the presence of resistant enterobacteriaceae must be assumed. Because of its broad spectrum of action, cefotaxime can to a large extent replace the combinations with aminoglycosides which were used previously. When required, cefotaxime proves to be a good partner for combinations with pseudomonas antibiotics.

Topics: Bacteroides Infections; Cefotaxime; Cefoxitin; Cephalosporins; Cross Infection; Drug Therapy, Combination; Enterobacteriaceae Infections; Gentamicins; Humans; Pseudomonas Infections; Staphylococcal Infections; Structure-Activity Relationship

Cefoxitin, a parenteral cephamycin beta-lactam antibiotic was prospectively evaluated as a single drug alternative in 31 children with cellulitis and the results of therapy were compared retrospectively with those from prevailing multiple antibiotic therapy for cellulitis in 56 children. Periorbital and lower extremity cellulitis accounted for more than 60% of the cases in both study groups. The most common bacterial agents included Haemophilus influenzae, Staphylococcus aureus, and group A beta-hemolytic Streptococcus. In as many as 50% of the cases, no etiologic agent could be found. In addition to blood cultures, cellulitis leading edge aspirate cultures were helpful in establishing the etiologic diagnosis. Of 52 patients sampled in the combined studies, 21% had positive aspirate cultures in the presence of negative blood cultures. The outcome and mean duration of hospital stay were similar in both groups. No severe adverse reactions were encountered. The mean number of antibiotics used in the retrospective study was three (range 1 to 7) whereas cefoxitin alone was used in the prospective study. All organisms isolated in the prospective study were susceptible to cefoxitin. Single antibiotic therapy with cefoxitin appears to be as safe and as effective in the treatment of cellulitis in children as multiple antibiotic therapy.

Topics: Anti-Bacterial Agents; Cefoxitin; Cellulitis; Child; Child, Preschool; Haemophilus Infections; Haemophilus influenzae; Humans; Infant; Male; Orbital Diseases; Prospective Studies; Retrospective Studies; Staphylococcal Infections; Streptococcal Infections; Streptococcus agalactiae