Emergence of OXA-204 β-lactamase in Tunisia.

A retrospective epidemiological survey was carried out to determine the prevalence of carbapenemase producers among enterobacterial clinical isolates recovered in the center of maternity and neonatology of Monastir (Tunisia). PCR screening identified 1 OXA-48 and 2 OXA-204 producers, which coexpressed the CTX-M-15 or the CMY-4 β-lactamases. PCR mapping showed that the bla(OXA-48) gene was carried by a Tn1999.2 transposon, whereas the bla(OXA-204) gene was part of the Tn2016 transposon-like structure. The OXA-48- or OXA-204-producing Klebsiella pneumoniae clinical isolates and the OXA-204-expressing Escherichia coli clinical isolate belonged to the widespread sequence types ST11, ST101, and ST617, respectively. The OXA-204 enzyme, which is a point derivative of the OXA-48 carbapenemase, had hitherto been reported in 2013 from K. pneumoniae isolate. Our study shows for the first time the dissemination of this resistance marker in E. coli strain. The coproduction of OXA-204 with CTX-M-15 and CMY-4 enzymes may potentiate the risk of multiresistance and may enhance the risk of dissemination.