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Characterizing Methicillin-Resistant Staphylococcus spp. and Extended-Spectrum Cephalosporin-Resistant Escherichia
Lisa Abdank1,2, Igor Loncaric2, Sascha D Braun3,4
1Clinical Centre for Ruminant and Camelid Medicine, University of Veterinary Medicine, 1210 Vienna, Austria.
Abstract:
In the field of cattle medicine in Austria, to date, few studies have investigated the presence of methicillin-resistant Staphylococcus aureus and extended-spectrum β-lactamase-producing Escherichia coli in Austria. For this reason, milk and nasal samples were examined for the presence of methicillin-resistant Staphylococcus aureus as well as fecal samples for extended-spectrum cephalosporin-resistant Escherichia coli. The nasal and fecal swabs were collected during the veterinary treatment of calf pneumonia and calf diarrhea. For the milk samples, the first milk jets were milked into a pre-milking cup and then the teats were cleaned and disinfected before the samples were taken. The cows were selected during the veterinary visits to the farms when treatment was necessary due to mastitis. Depending on the severity of the mastitis (acute mastitis or subclinical mastitis), antibiotics and non-steroidal anti-inflammatory drugs were given immediately (acute disease) or after completion of the antibiogram (subclinical disease). Isolates were characterized by a polyphasic approach including susceptibility pheno- and genotyping and microarray-based assays. No methicillin-resistant Staphylococcus aureus was found in the milk samples, but one nasal swab was positive for methicillin-resistant Staphylococcus aureus. Twenty-two Escherichia coli isolates were detected among the fecal samples. All the Escherichia coli isolates were resistant to ceftazidime. In all the Escherichia coli isolates, genes from the blaCTX family were detected with other bla genes or alone; the most frequently observed β-lactamase gene was blaCTX-M-1/15 (n = 20). In total, 63.6% (n = 14) of the isolates exhibited a multidrug-resistant phenotype and one E. coli isolate (4.5%) harbored the AmpC gene. Precisely because the presence of data regarding extended-spectrum cephalosporin-resistant Escherichia coli and methicillin-resistant Staphylococcus aureus in calves and cows in Austria is rare, this study further expands our understanding of antimicrobial resistance in Austrian cattle, which is highly relevant for successful antibiotic therapy in sick cattle.
Insights
Methicillin-resistant Staphylococcus aureus was detected in one nasal swab, and multidrug-resistant, extended-spectrum cephalosporin-resistant Escherichia coli, often carrying blaCTX-M genes, were found in Austrian cattle fecal samples. This study highlights critical antimicrobial resistance concerns in Austrian cattle populations.
Area of Science:
- Veterinary Medicine
- Microbiology
- Antimicrobial Resistance
Background:
- Limited data exists on methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum cephalosporin-resistant Escherichia coli (ESCCEC) in Austrian cattle.
- Antimicrobial resistance (AMR) in livestock poses a significant threat to animal and public health.
Purpose of the Study:
- To investigate the prevalence of MRSA in milk and nasal samples and ESCCEC in fecal samples from Austrian cattle.
- To characterize the antimicrobial resistance profiles and genetic determinants of detected isolates.
Main Methods:
- Collection of milk, nasal, and fecal samples from cattle during veterinary treatments for mastitis, pneumonia, and diarrhea.
- Phenotypic and genotypic characterization of isolates, including antimicrobial susceptibility testing and microarray analysis.
- Detection of specific resistance genes like blaCTX and AmpC.
Main Results:
- MRSA was identified in one nasal swab; no MRSA was found in milk samples.
- All 22 Escherichia coli fecal isolates were resistant to ceftazidime, with 63.6% exhibiting multidrug resistance.
- The blaCTX-M-1/15 gene was the most frequent beta-lactamase gene detected in E. coli isolates.
Conclusions:
- This study provides crucial data on AMR in Austrian cattle, identifying MRSA and ESCCEC.
- The findings underscore the importance of monitoring AMR in livestock for effective antibiotic therapy and disease control.
- Further research is needed to understand the transmission dynamics and impact of these resistant bacteria in the cattle population.
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