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The Japanese Journal of Antibiotics
Vol.76 No.4 December 2023

◆原著

Contamination rate of broad-spectrum cephalosporin-resistant Enterobacterales isolated from domestic and imported retail chicken meat in Tokyo and Kanagawa, Japan
Yuya Hasunuma, Nozomi Hiyoshi, Masaya Tanaka and Yoshikazu Tokuoka
P.121-134, 2023

 Extended-spectrum cephalosporin-resistant Enterobacterales are among the most prevalent antimicrobial-resistant organisms in Gram-negative bacteria, and their spread in the veterinary field is of global concern. We determined the contamination rate of extended-spectrum cephalosporin-resistant Enterobacterales in domestic and imported retail chickens in Japan, and examined their antimicrobial resistance and molecular characteristics. Fifty-three domestic and thirty-nine imported retail chickens were purchased, and antimicrobial susceptibility, β-lactamase encoding genes, sequence type, and incompatibility type of plasmids were assessed in the isolates. The contamination rates of cefotaxime-resistant Enterobacterales isolated from domestic and imported retail chickens were 60.4% and 87.2%, respectively (p < 0.05). Approximately 50% of isolates harbored the blaCTX-M gene, with blaCTX-M-1 and blaCTX-M-2 groups predominating domestic and imported samples, respectively. The gene for plasmid-mediated AmpC was detected in 34% and 33% of isolates from domestic and imported samples, respectively. Isolates possessing blaCIT with IncK plasmids were found in the isolates from both sample groups. Additionally, our results indicated that the IncK plasmid had the potential for transconjugation with blaCIT. Escherichia coli sequence type (ST) 57 and ST117 were predominant, followed by ST38. The findings of this study suggest that the high contamination rate of drug-resistant bacteria in retail chicken meat leads to frequent exposure to these pathogens by the general public in Tokyo and Kanagawa, Japan.