The sequences of seven class D β-lactamases isolated from carbapenem-resistant Acinetobacter baumannii from four continents

Carbapenem resistance associated with class D β-lactamases is an increasing problem in Acinetobacter baumannii. Most enzymes of this class reported so far belong to two subgroups, 1 and 2; however, a novel class D carbapenemase (OXA-51) has been reported recently which shares 56% and <63% amino-acid identity with subgroups 1 and 2, respectively, and which belongs to a third subgroup. This study describes a further seven novel subgroup 3 β-lactamases in carbapenem-resistant A. baumannii isolates from four continents.