Multicenter collaboration study on the β-lactam resistant Enterobacteriaceae in Japan - The 65th anniversary public interest purpose project of the Japanese Society of Chemotherapy.

This study was conducted using the same method of the "1-day multicenter collaborative research for Clostridium difficile infectious". This surveillance study was performed by 38 participating medical facilities across Japan. Of the 268 fecal specimens collected in this study, 5 (1.9%) carbapenem-resistant Enterobacteriaceae (CRE) were judged carbapenem resistant by the criteria of the Infectious Disease Act, Japan (2 mg/L or more and 64 mg/L or more MICs for imipenem and cefmetazole, respectively). However, no isolate was shown to have a meropenem MIC of 2 mg/L or more. No carbapenemase encoding genes were detected from the CRE. Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae were detected from 29 specimens (11%), and the predominant ESBL-encoding gene group was blaCTX-M-9. The predominant ST-type by multilocus sequence typing of ESBL encoding gene-positive Escherichia coli was ST131.