cefoxitin and Mastitis--Bovine

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

This study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci.. Isolation was performed on blood agar and identification was based on biochemical reactions. Antimicrobial susceptibility was according to the Clinical and Laboratory Standards Institute guidelines. The antimicrobial resistance genes, SCC. We isolated a total of 185 staphylococci and 28 streptococci from 148 milk samples. Among the staphylococcal isolates, 154 were identified as CNS and 31 as. The present findings of this study indicate a development of antimicrobial resistance in main bacteria isolated from cows with mastitis in Argentina.

Topics: Animals; Anti-Bacterial Agents; Argentina; Cattle; Cattle Diseases; Cefoxitin; Clindamycin; Drug Resistance, Bacterial; Erythromycin; Female; Mastitis, Bovine; Oxacillin; Staphylococcus; Staphylococcus aureus; Streptococcus

The present study investigated the effects of N-acetylcysteine (NAC) on β-lactam antibacterial activity against 20 methicillin-resistant Staphylococcus aureus (MRSA) isolates from bovine mastitis. Minimum inhibitory concentrations (MIC) were determined by the E-test method. The presence of 10 mM NAC reduced the MIC of penicillin, ampicillin, oxacillin, cefoxitin, ceftazidime, and cefotaxime to MRSA. Importantly, the MIC of cefoxitin in MRSA in the presence of NAC was lower than the susceptible breakpoint of cefoxitin. The results provide a new way to use current β-lactam antibiotics combined with NAC against MRSA.

Topics: Acetylcysteine; Ampicillin; Animals; Anti-Bacterial Agents; beta-Lactams; Cattle; Cefoxitin; Female; Mastitis, Bovine; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Oxacillin; Penicillin G

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

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

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

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