First report of the isolation of blaIMI-1-producing colistin-heteroresistant Enterobacter cloacae in Japan, September 2016.

The isolation of a carbapenem-resistant Enterobacter cloacae strain harboring the IMI-1 variant of blaIMI-1 carbapenemase points to the worldwide emergence of multidrug resistant bacteria as a potential source of health care infections. In this report, we describe the first isolation of E. cloacae with blaIMI-1 carbapenemase isolated from a Japanese patient in September 2016. The isolate was resistant to carbapenems, levofloxacin, and aminoglycosides, and heteroresistant to colistin but sensitive to fourth-generation cephalosporins. All microbiology laboratories worldwide should be made aware of these blaIMI-1-producing subtypes with unusual antibiotic susceptibility profiles.