Identification of Diverse OXA-40 Group Carbapenemases, Including a Novel Variant, OXA-160, fromAcinetobacter baumanniiin Pennsylvania

Abstract

Three Acinetobacter baumannii isolates that possess OXA-40 group carbapenemase genes were identified. They belonged to novel sequence types (ST122, ST123, and ST124) and harbored bla _OXA-160, bla _OXA-72, and bla _OXA-40, respectively. OXA-160 is a novel variant of OXA-40 with a P227S substitution. An isogenic Escherichia coli clone producing OXA-160 was more susceptible to carbapenems than a clone producing OXA-40. The genetic environment of bla _OXA-160 and bla _OXA-40 beyond the putative XerC/XerD recombination sites was distinct from the scaffold reported previously.