agar and Sepsis

The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. The 2022 survey was the tenth year to focus on blood stream infections caused by Enterobacterales, and the eighth year where Pseudomonas aeruginosa and Acinetobacter species were included. Fifty-five hospitals Australia-wide participated in 2022. The 2022 survey tested 9,739 isolates, comprising Enterobacterales (8,773; 90.1%), P. aeruginosa (840; 8.6%) and Acinetobacter species (126; 1.3%), using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2023). Key resistances included resistance to the third-generation cephalosporin ceftriaxone in 12.7%/12.7% (CLSI/EUCAST criteria) of Escherichia coli and in 6.6%/6.6% of Klebsiella pneumoniae complex. Resistance rates to ciprofloxacin were 13.7%/13.7% for E. coli; 7.8%/7.8% for K. pneumoniae complex; 5.3%/5.3% for Enterobacter cloacae complex; and 4.3%/10.0% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 2.8%/5.9%; 2.9%/8.7%; 18.3%/27.2%; and 6.1%/14.7% for the same four species, respectively. Twenty-nine Enterobacterales isolates from 28 patients were shown to harbour a carbapenemase gene: 18 blaIMP-4; four blaNDM-5; three blaNDM-1; one blaOXA-181; one blaOXA-244; one blaNDM-1 + blaOXA-181; and one blaNDM-5 + blaOXA-181. Transmissible carbapenemase genes were also detected among two Acinetobacter baumannii complex isolates (blaOXA-23) and one P. aeruginosa (blaNDM-1) in the 2022 survey.

Topics: Agar; Anti-Bacterial Agents; Australia; Drug Resistance, Bacterial; Escherichia coli; Humans; Klebsiella pneumoniae; Pseudomonas aeruginosa; Sepsis

The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. The 2020 survey was the eighth year to focus on bloodstream infections caused by Enterobacterales, and the sixth year in which Pseudomonas aeruginosa and Acinetobacter species were included. Eight thousand seven hundred and fifty-two isolates, comprising Enterobacterales (7,871, 89.9%), P. aeruginosa (771, 8.8%) and Acinetobacter species (110, 1.3%), were tested using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2021). Of the key resistances, resistance to the third-generation cephalosporin ceftriaxone was found in 13.5%/13.5% (CLSI/EUCAST criteria) of Escherichia coli and 8.7%/8.7% of Klebsiella pneumoniae. Resistance rates to ciprofloxacin were 16.1%/16.1% for E. coli; 9.9%/9.9% for K. pneumoniae; 5.8%/5.8% for Enterobacter cloacae complex; and 4.5%/8.1% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 2.5%/6.6%; 3.9%/12.5%; 16.9%/26.3%; and 5.5%/14.4% for the same four species respectively. Thirty-two isolates from 32 patients were shown to harbour at least one carbapenemase gene: 19 blaIMP-4, three blaGES-5, two blaNDM-1, two blaNDM-5, two blaOXA-48, two blaOXA-181, one blaIMI-1, and one blaOXA-23+NDM-1.

Topics: Agar; Anti-Bacterial Agents; Australia; Drug Resistance, Bacterial; Escherichia coli; Humans; Microbial Sensitivity Tests; Sepsis

Bloodstream infections have been the leading complications in cancer patients because they are at high risk for antibiotic-resistant bacterial infections. There is increasing evidence from different parts of the world of the high prevalence of antimicrobial-resistant bacterial strains in cancer patients. The burden of the infection is high in developing countries, especially in Ethiopia. Data on bacterial profile and antimicrobial susceptibility patterns among cancer patients in Ethiopia is limited. Thus, this study aimed to determine the predominant bacterial species causing bacteremia and their antibiotic resistance pattern among cancer patients at University of Gondar comprehensive specialized hospital.. A hospital-based, cross-sectional study was conducted on 200 study participants from March to July 2021. All cancer patients who developed a fever at the time of hospital visit were included in this study, and their socio-demographic and clinical data were collected using a structured questionnaire. Blood samples (10 mL for adults and 4 mL for children) were collected from each patient, and the collected blood samples were transferred into sterile tryptic soy broth, then incubated at 37°C for 7 days. Tryptic soy broth which showed signs of growth were Gram-stained and sub-cultured on blood agar, chocolate agar, MacConkey agar, and mannitol salt agar. The inoculated plates were then aerobically incubated at 37°C for 18-24 hours and the isolates obtained were identified using standard microbiological methods. Antimicrobial susceptibility tests were done using a modified Kirby-Bauer disk diffusion technique following CLSI 2021 guidelines. Data were entered using EPI data version 4.6 and analyzed with SPSS version 20.. In this study, out of 200 cancer patients included and 67.5% (135/200) of them were males. The majorities of study participants, 56% (113/200) of cancer patients were pediatrics and 26.5% (53/200) of them belong under five years of age. Out of 200 patient samples that had undergone culture, 27% (54/200) samples had bacterial growth. Gram-positive bacterial isolates were predominant, 61.1%, and S. aureus was the predominant Gram-positive isolate, (51.5.6%), followed by coagulase-negative staphylococci (48.5%). Moreover, K. pneumoniae (47%) and P. aeruginosa (29.5%) were the most common Gram-negative bacterial isolates. Among patients who had BSIs, the highest prevalence of BSIs was observed among males (66.7%), and in pediatrics cancer patients (44.2%). Pediatric study participants were more venerable to bloodstream infection (P = 0.000) compared to adult participants. Meropenem (100%), amikacin (100%), piperacillin/tazobactam (72.3%), and ceftazidime (73.5%) were effective against for Gram-negative isolates while cefoxitin (81.2%) and penicillin (70.5%) were effective for Gram-positive isolates. Additionally, most Gram-negative and Gram-positive bacterial isolates were sensitive for gentamycin (75.9%). Multidrug resistance was seen among 17.1% bacterial isolates, and MDR in Gram-negative and Gram-positive bacteria were 83.3% and 16.7%, respectively. Gram-negative bacterial isolates showed a high prevalence of MDR than Gram-positive isolates.. BSI's remains an important health problem in cancer patients, and Gram-positive bacteria were more common as etiologic agents of BSIs in cancer patients. S. aureus was the dominant bacteria followed by CoNS, K. pneumoniae, and P. aeruginosa. Multidrug-resistant isolates found in cancer patients and routine bacterial surveillance and study of their resistance patterns may guide successful antimicrobial therapy and improve the quality of care. Therefore, strict regulation of antibiotic stewardship and infection control programs should be considered in the study area.

Topics: Adult; Agar; Anti-Bacterial Agents; Bacteria; Child; Cross-Sectional Studies; Drug Resistance, Multiple, Bacterial; Ethiopia; Female; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Male; Microbial Sensitivity Tests; Neoplasms; Sepsis; Staphylococcus aureus

From 1 January to 31 December 2020, forty-nine institutions around Australia participated in the Australian Enterococcal Sepsis Outcome Programme (AESOP). The aims of AESOP 2020 were to determine the proportion of enterococcal bacteraemia isolates in Australia that were antimicrobial-resistant, and to characterise the molecular epidemiology of the E. faecium isolates. Of the 1,230 unique episodes of enterococcal bacteraemia investigated, 93.9% were caused by either E. faecalis (54.2%) or E. faecium (39.7%). Ampicillin resistance was not detected in E. faecalis but was detected in 88.2% of E. faecium . Vancomycin non-susceptibility was detected in 0.2% of E. faecalis and 32.6% of E. faecium . Overall, 35.2% of E. faecium harboured vanA and/or vanB genes. For the vanA/B positive E. faecium isolates, 38.8% harboured the vanA gene, 60.6% the vanB gene, and 0.6% harboured both vanA and vanB . Although the percentage of E. faecium bacteraemia isolates was significantly lower than that detected in the 2019 AESOP (presumably due to the COVID-19 elective surgery restrictions placed on hospitals), it remains substantially higher than that recorded in most European countries. The E. faecium isolates detected consisted of 71 multilocus sequence types (STs), with 81.7% of these isolates classified into eight major STs each containing ten or more isolates. All major STs belonged to clonal cluster 17 (CC17), a major hospital-adapted polyclonal E. faecium cluster. The major STs (ST17, ST1424, ST80, ST796, ST78, ST1421, ST555 and ST117) were found across most regions of Australia. The predominant clone was ST17, which was identified in all regions except the Northern Territory. Overall, 40.9% of isolates belonging to the eight major STs harboured the vanA or vanB gene. The AESOP 2020 has shown enterococcal bacteraemia episodes in Australia are frequently caused by polyclonal ampicillin-resistant high-level gentamicin-resistant vanA - or vanB -positive E. faecium which have limited treatment options.

Topics: Agar; Anti-Bacterial Agents; Bacteremia; COVID-19; Drug Resistance, Bacterial; Enterococcus; Gram-Positive Bacterial Infections; Humans; Northern Territory; Sepsis

From 1 January to 31 December 2020, forty-nine institutions around Australia participated in the Australian Staphylococcus aureus Sepsis Outcome Programme (ASSOP). The aims of ASSOP 2020 were to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that were antimicrobial resistant, with particular emphasis on susceptibility to methicillin; and to characterise the molecular epidemiology of the methicillin-resistant isolates. A total of 2,734 SAB episodes were reported, of which 79.7% were community-onset. Of S. aureus isolates, 17.6% were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 14.2%, which was not significantly different from the 13.3% mortality associated with methicillin-susceptible SAB (p = 0.6). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However, in addition to the β-lactams, approximately 35% of methicillin-resistant S. aureus (MRSA) were resistant to erythromycin, 33% to ciprofloxacin, 13% to tetracycline, 13% to gentamicin and 4% to co-trimoxazole. When applying the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, teicoplanin resistance was detected in four S. aureus isolates. Resistance was not detected for vancomycin and linezolid. Resistance to non-beta-lactam antimicrobials was largely attributable to two healthcare-associated MRSA (HA-MRSA) clones: ST22-IV [2B] (EMRSA-15) and ST239-III [3A] (Aus-2/3 EMRSA). The ST22-IV [2B] (EMRSA-15) clone is the predominant HA-MRSA clone in Australia. However, 85% percent of methicillin-resistant SAB isolates were community-associated MRSA (CA-MRSA) clones. Although polyclonal, approximately 77% of CA-MRSA clones were characterised as: ST93-IV [2B] (Queensland CA-MRSA); ST5-IV [2B]; ST45-V [5C2&5]; ST1-IV [2B]; ST30-IV [2B]; ST8-IV [2B]; and ST97-IV [2B]. The CA-MRSA clones, in particular ST45-V [5C2&5], have acquired multiple antimicrobial resistance determinants including ciprofloxacin, erythromycin, clindamycin, gentamicin and tetracycline. The multi-resistant ST45-V [5C2&5] clone accounted for 11.0% of CA-MRSA. As CA-MRSA is well established in the Australian community, it is important to monitor antimicrobial resistance patterns in community- and healthcare-associated SAB as this information will guide therapeutic practices in treating S. aureus sepsis.

Topics: Agar; Anti-Bacterial Agents; Anti-Infective Agents; Australia; Bacteremia; Ciprofloxacin; Cross Infection; Drug Resistance, Bacterial; Erythromycin; Gentamicins; Humans; Methicillin; Methicillin-Resistant Staphylococcus aureus; Sepsis; Staphylococcal Infections; Staphylococcus aureus; Tetracyclines

Thymine auxotrophic in vitro mutants of Escherichia coli were first reported in the mid-20th century. Later, thymine-dependent clinical strains of E. coli as well as other Enterobacterales, Enterococcus faecalis and Staphylococcus aureus have been recognized as the cause of persistent and recurrent infections.. The aim of this study was to characterize the phenotype and investigate the molecular basis of thymine auxotrophy in ten E. coli isolates obtained at different time points from a patient with recurrent bloodstream infection (BSI) due to a chronic aortic graft infection treated with Trimethoprim/sulfamethoxazole (TMP-SMX).. Clinical data was obtained from hospital records. Growth characterization and antimicrobial susceptibility testing to TMP-SMX was performed on M9 agar and in MH broth with different thymine concentrations (0.5, 2, 5, 10 and 20 μg/mL), on Mueller-Hinton (MH) and blood agar. Whole genome sequencing (WGS) was performed on all E. coli isolates.. E. coli were isolated from ten consecutive BSI episodes from a patient with chronic aortic graft infection. Six of these isolates were resistant to TMP-SMX when assayed on blood agar. Growth experiments with added thymine confirmed that these isolates were thymine-dependent (thy-), and revealed growth defects (slower growth rate and smaller colony size) in these isolates relative to thy+ isolates (n = 4). WGS indicated that all isolates were of the same clonal lineage of sequence type 7358. Genomic analysis revealed a G172C substitution in thyA in all TMP-SMX resistant isolates, while mutations affecting genes involved in the deoxyribose salvage pathway (deoB and deoC) were identified in eight isolates.. This case highlights the risk of resistance development to TMP-SMX, especially for long-term treatment, and the possible pitfalls in detection of growth-deficient subpopulations from chronic infections, which could lead to treatment failure.

Topics: Agar; Anti-Bacterial Agents; Escherichia coli; Escherichia coli Infections; Humans; Microbial Sensitivity Tests; Phenotype; Reinfection; Sepsis; Thymine; Trimethoprim, Sulfamethoxazole Drug Combination

Mycobacterium spp. are a rare cause of endocarditis. Herein, we describe a case of Mycobacterium mageritense prosthetic valve endocarditis. This organism produced an unusual brown pigment on solid media. Cultures of valve tissue for acid-fast bacilli might be considered in some cases of apparently culture-negative prosthetic valve endocarditis.

Topics: Agar; Bacteriological Techniques; Culture Media; Endocarditis; Female; Humans; Microscopy; Middle Aged; Mycobacterium; Mycobacterium Infections, Nontuberculous; Pigments, Biological; Prosthesis-Related Infections; Sepsis

Each of 1,018 blood culture specimens was inoculated into Bactec 6B (Johnston Laboratories, Towson, MD) and a biphasic blood culture system that incorporates internal removable agar dip slides (Hylab). Ninety clinically significant pathogens were recovered: 66 from both systems, 14 from Bactec only, and 10 from Hylab only. The mean incubation times to positive of the two systems did not differ when data were examined for gram-negative bacilli, gram-positive cocci, total isolates, and contaminants (P greater than 0.05). Contamination rates were also comparable: Bactec 5.4%, Hylab 7.3% (P greater than 0.05). The Hylab system may offer a practical alternative to Bactec 6B.

Topics: Agar; Bacteriological Techniques; Blood; Humans; Sepsis

A strain of Salmonella choleraesuis subsp. choleraesuis serovar paratyphi-A isolated from the blood of a febrile patient grew into filaments on a nutrient agar containing various salts, such as NaCl, KCl, MgCl2, NH4Cl, (NH4)2SO4, or (NH4)2HPO4, at concentrations of 50 to 400 mM. The filamentous cells were nonseptate and multinucleate, and they had colony-forming ability. This mutant strain, however, did not show filamentous growth in liquid media which contained the same salts. On nutrient agar containing 20% sucrose but no salts, some of the cells formed large spheroplasts. Both ampicillin treatment and in vivo environment may in part be responsible for the induction of the mutant strain.

Topics: Adolescent; Agar; Ammonium Chloride; Ammonium Sulfate; Culture Media; Humans; Magnesium; Magnesium Chloride; Male; Mutation; Osmotic Pressure; Potassium Chloride; Salmonella; Salmonella Infections; Sepsis; Sodium Chloride

An albumin polysorbate semisolid medium (Ellinghausen McCullough Johnson Harris medium) gelled with gellan gum (Gelrite; Kelco Div., Merck & Co., Inc.) compared favorably with conventional agar media for the cultivation of both pathogenic and saprophytic leptospires. The gellan gum medium supported the growth of all 18 leptospiral strains studied which included an array of serovars with various fastidious growth characteristics. Gellan gum medium was also used advantageously as a long-term maintenance medium; 9- to 12-month-old cultures still contained viable organisms. The colonial growth in gellan gum plating medium of six representative strains was consistent with previously described colonial growth on agar plating media. In addition, gellan gum medium appeared to be an excellent medium for the recovery of leptospires from the blood, liver, and kidneys of hamsters experimentally infected with a virulent Leptospira interrogans serovar bataviae strain. As few as 1 to 10 organisms in the infective tissue could be recovered in semisolid Ellinghausen McCullough Johnson Harris-gellan gum medium. The antigenicity did not appear to be affected by growth in gellan gum medium. The hamster-virulent strain of L. interrogans serovar bataviae isolated from a moribund hamster maintained its virulence after 10 sequential passages in gellan gum medium. Gellan gum medium can be a valuable adjunct to currently used cultural procedures.

Topics: Agar; Animals; Cricetinae; Culture Media; Kidney; Leptospira; Leptospira interrogans; Liver; Polysaccharides; Polysaccharides, Bacterial; Polysorbates; Sepsis; Virulence; Weil Disease

The Roche Septi-Chek biphasic blood culture system with tryptic soy broth was compared with a conventional blood culture bottle with supplemented peptone broth in 6,956 paired blood cultures from adult patients. Both systems were inoculated with equal volumes of blood (5 ml) and incubated aerobically (vented) for 2 weeks. More clinically important bacteria and fungi, including Staphylococcus aureus, S. epidermidis, Escherichia coli and other Enterobacteriaceae, Pseudomonas aeruginosa, and Candida albicans and C. tropicalis were recovered from the biphasic system (P less than 0.001). In contrast, more clinically important anaerobic bacteria (P less than 0.001) and Gardnerella vaginalis (P less than 0.05) were recovered in conventional supplemented peptone broth. Staphylococci (P less than 0.01), Enterobacteriaceae other than E. coli (P less than 0.05), and fungi (P less than 0.001) were detected 1 or more days earlier in the biphasic system, whereas streptococci (P less than 0.001) were detected earlier in the conventional bottle. The overall superiority of the agar slide blood culture system compared with conventional blood culture bottles was confirmed by this evaluation. For optimal detection of anaerobic bacteremia, however, the agar slide bottle should be paired with an anaerobic bottle.

Topics: Agar; Bacteria; Blood; Culture Media; Fungi; Humans; Peptones; Sepsis

A blood isolate of Pseudomonas aeruginosa was encountered which produced, on subculture to Mueller-Hinton agar, markedly adherent, tenacious colonies which were characterized microscopically by the presence of serpentine rows of interlocking bacilli. Factors accounting for the observed morphologic aberration, which was lost upon subculture, remain unknown.

Topics: Agar; Child, Preschool; Female; Humans; Pseudomonas aeruginosa; Pseudomonas Infections; Sepsis; Urinary Tract Infections

Both prereduced molten agar and broth and aerobic molten agar and broth were inoculated with blood samples collected from patients with periodontitis, but in otherwise good health, both before and after extraction of two or more teeth. Postoperative blood samples from 23 of 25 patients sampled yielded anaerobic and facultative species. Colony counts from nine samples yielded from less than 1 to over 100 colonies per ml of blood. Organisms detected were species belonging to the genera Bacteroides, Fusobacterium, Peptostreptococcus, Leptotrichia, Propionibacterium, Peptococcus, Veillonella, plus Streptococcus mitis, S. salivarius, vibrio forms, and strains resembling S. mutans. The data indicate that prereduced anaerobically sterilized culture medium with polyanethol sulfonate is effective for detecting anaerobic species in bacteremia and that anaerobic species can be prevalent in bacteremias immediately after tooth extraction in patients with periodontitis.

Topics: Aerobiosis; Agar; Anaerobiosis; Animals; Anticoagulants; Bacteria; Bacteriological Techniques; Culture Media; Gastric Juice; Humans; Periodontitis; Postoperative Complications; Rumen; Sepsis; Sterilization; Sulfonic Acids; Tooth Extraction

Topics: Adolescent; Adult; Agar; Aged; Animals; Anti-Bacterial Agents; Bacteriological Techniques; Bile; Caniformia; Carrier State; Child; Child, Preschool; Citrates; Disease Reservoirs; Drug Resistance, Microbial; Enterobacteriaceae; Enterobacteriaceae Infections; Feces; Female; Gastroenteritis; Humans; Indoles; Infant; Male; Middle Aged; Rectum; Reptiles; Sepsis; Thailand; Zoonoses

Topics: Agar; Animals; Bone Marrow; Bone Marrow Cells; Cerebrospinal Fluid; Culture Techniques; Humans; Leukemia; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Mice; Retroviridae; Sepsis

Topics: Agar; Amphotericin B; Candida; Candidiasis; Endocarditis; Fluorescent Antibody Technique; France; Humans; Immunodiffusion; Immunoelectrophoresis; Nystatin; Precipitins; Sepsis

Topics: Agar; Animals; Animals, Laboratory; Arthritis, Infectious; Cricetinae; Culture Media; Culture Techniques; Disease Models, Animal; Freund's Adjuvant; Guinea Pigs; Injections; Injections, Intraperitoneal; Lymphoma, Non-Hodgkin; Methylcellulose; Mice; Mucins; Mycoplasma; Mycoplasma Infections; Rabbits; Rats; Sarcoma, Experimental; Sepsis; Silicon Dioxide; Talc; Virulence