Characterizing Methicillin-Resistant Staphylococcus spp. and Extended-Spectrum Cephalosporin-Resistant Escherichia coli in Cattle

In the field of cattle medicine in Austria, to date, few studies have investigated the presence of methicillin-resistant and extended-spectrum β-lactamase-producing in Austria. For this reason, milk and nasal samples were examined for the presence of methicillin-resistant as well as fecal samples for extended-spectrum cephalosporin-resistant . 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 was found in the milk samples, but one nasal swab was positive for methicillin-resistant . Twenty-two isolates were detected among the fecal samples. All the isolates were resistant to ceftazidime. In all the isolates, genes from the family were detected with other genes or alone; the most frequently observed β-lactamase gene was (n = 20). In total, 63.6% (n = 14) of the isolates exhibited a multidrug-resistant phenotype and one isolate (4.5%) harbored the AmpC gene. Precisely because the presence of data regarding extended-spectrum cephalosporin-resistant and methicillin-resistant 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.