Third-Generation Cephalosporin Resistance in Intrinsic Colistin-Resistant Enterobacterales Isolated from Retail Meat.

Consumption of retail meat contaminated with antimicrobial-resistant (AMR) bacteria is a common route for transmitting clinically relevant resistant bacteria to humans. Here, we investigated the genotypic and phenotypic resistance profiles of intrinsic colistin-resistant (ICR) Enterobacterales isolated from retail meats. ICR Enterobacterales were isolated from 103 samples of chicken, 103 samples of pork, and 104 samples of beef purchased from retail shops in Japan, using colistin-containing media, and their antimicrobial susceptibility was examined. spp. (440 isolates) showed resistance to cefotaxime (19 isolates, 4.3%), tetracycline (15 isolates, 3.4%), and other antimicrobials (<1%). spp. (136) showed resistance to cefotaxime (12 isolates, 8.6%), ceftazidime (four isolates, 2.9%), and tetracycline (two isolates, 1.4%). spp. (39) showed resistance to chloramphenicol (four isolates, 10.3%), sulfamethoxazole-trimethoprim (four isolates, 10.3%), cefotaxime (two isolates, 5.1%), kanamycin (two isolates, 5.1%), and gentamicin (one isolate, 2.6%). spp. (22) were resistant to tetracycline (two isolates, 9.1%) whereas spp. (11) were resistant to tetracycline (four isolates, 36.4%) and chloramphenicol (one isolate, 9.2%). The resistance genes , , and were detected in cefotaxime-resistant spp., spp., and spp. isolates, respectively. This emergence of antimicrobial resistance in ICR Enterobacterales may pose a public health risk.