Plasmid harboring resistance genes. Escherichia coli

Antimicrobial-resistant (AMR) bacteria in humans and animals has an impact on the environment. In 2015, we isolated CTX-M-14-producing E. coli from Siberian weasels (SWs) captured in the university. Thus, to clarify the source of AMR bacteria in SWs, we examined AMR bacteria in animals on this campus. Eighty-eight fecal samples of domestic animals and wild rats were collected from animal facilities in 2016. The third-generation cephalosporin (TGC)-resistant strains were picked up from DHL containing cephalexin (50 mg/mL) or cefotaxime (2 mg/mL) and were subjected to antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), replicon typing, b-lactamase typing and next-generation sequencing. The CTX-M-14- and CMY-2-producing strains were detected on this campus. CTX-M-14 producers from domestic animals and SWs were classified into 6 clusters (7 PFGE profiles). The PFGE and AMR profiles were characteristic based on animal facility. All CTX-M-14 plasmids belonged to IncI1. Most of plasmids had a similar size (98.9-99.3 kb) except for one plasmid (105.5 kb). The recombination network analysis revealed that CTX-M-14 plasmid in SW isolates may be originated from plasmids which evolved among domestic animals in the university campus.