Plasmid-mediated AmpC β-lactamase (CMY-2) gene in Salmonella typhimurium isolated from diarrheic pigs in South Korea

ABSTRACTS: BACKGROUND: Salmonella resistant to third-generation cephalosporin has been isolated from an increasing number of animals worldwide. The purpose of this study was to examine ESBL (extended-spectrum β-lactamases)-producing and PABL (plasmid-mediated AmpC β-lactamases)-producing Salmonella isolates from pigs in South Korea. RESULTS: Salmonella Typhimurium KVCC-BA1300259 was resistant to ampicillin, amoxicillin/clavulanic acid, cephalothin, chloramphenicol, florfenicol, cefoxithin, gentamicin, nalidixic acid, trimethoprim/sulfamethoxazole, tetracycline, and ceftiofur. The results of a double-disk synergy test and PCR confirmed that the isolate produced CMY-2 (PABL). Analysis of plasmid incompatibility (Inc) groups revealed the presence of IncA/C and IncFIB, indicating antimicrobial resistance. This study is the first to identify S. Typhimurium isolates harboring CMY-2 in pigs in South Korea. CONCLUSIONS: The presence of CMY-2 in pigs poses a significant threat of possible horizontal spread between animals and humans.