A carbapenem-resistant clinical isolate of Aeromonas hydrophila in Japan harbouring an acquired gene encoding GES-24 β-lactamase

Several species of Aeromonas produce the enzyme CphA metallo-β-lactamase. This study describes an isolate of Aeromonas hydrophila harbouring an acquired gene encoding the carbapenemase GES-24. This isolate was obtained from an inpatient in Okinawa, Japan, with no apparent record of travelling overseas. The minimum inhibitory concentrations of carbapenems against this isolate were 8 µg ml for imipenem and 16 µg ml for meropenem. Recombinant GES-24 hydrolyzed all of the tested β-lactams, including imipenem and meropenem. The genomic environment surrounding blaGES-24 was intI1-blaGES-24-aac(6')-IIc-qacEdelta1-sulI-orfX-tetR-tetE. This is the first report of A. hydrophila producing a GES-type carbapenemase.