Extended spectrum cephalosporin-resistant Escherichia coli on dairy farms

The intestinal tracts of farm animals including dairy cattle are important reservoirs of extended-spectrum ß-lactamase (ESBL) producing, especially, third generation cephalosporin (3GC)-resistant E. coli. We found E. coli isolates that were resistant to 3GC but sensitive to 2GC (e.g., cefoxitin) from dairy farms. For further insight of antimicrobial resistance patterns of 3GC-resistant E. coli on dairy farms, whole genome sequencing was performed.