Prevalence of fecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae among healthy adult people in Japan

In Japan, the prevalence of extended-spectrum β-lactamase (ESBL) producers in hospital settings has shown an increasing trend. In the present study, we investigated the prevalence of the fecal carriage of ESBL-producing Enterobacteriaceae among healthy adults. Stool samples were collected for the phenotypic and genotypic identification of ESBL-producing Enterobacteriaceae. We found the prevalence of ESBL producers to be 6.4% by phenotypic identification, and 92.9% of them possessed the blaCTX-M gene. Among the CTX-M ESBL-producing Enterobacteriaceae, we identified 11 Escherichia coli and 2 Klebsiella pneumonia strains. The findings suggest that the fecal carriage of CTX-M-type ESBL producers by healthy people is rapidly increasing in Japan. This may be one of the causes of the increased spread of ESBL-producing bacteria in hospitals.