Molecular Epidemiological Analyses of Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolated from Sporadic Diarrheal Human Cases and Chicken Meats in Fukui Prefecture

Abstract

We investigated the molecular-epidemiological characteristics of 16 chicken and 22 human isolates of extended-spectrum β-lactamase-producing Escherichia coli. Serotypes of O78:H9 and O25:H4 were mainly found in the chicken isolates. On the other hand, serovars of O1:H6, O25:H4 and O86a:H18 were identified in the human isolates. For serovars O25:H4, the CTX-M type of chicken isolate was CTX-M-3, and those of human isolates were CTX-M-14 and CTX-M-27. No CTX-M-15-producing E. coli O25:H4 epidemic strain emerging outside of Japan was isolated. The minimal inhibitory concentrations of Ceftoriaxon for chicken isolates were higher than those for human isolates (P ＜0.01). No clear direct relationship between human and chicken isolates regarding the CTX-M type and antimicrobial susceptibility was observed in the present study.