A Novel VIM-Type Metallo-β-Lactamase Variant, VIM-60, with Increased Hydrolyzing Activity against Fourth-Generation Cephalosporins in Pseudomonas aeruginosa Clinical Isolates in Japan.

A novel VIM-type metallo-β-lactamase variant, VIM-60, was identified in multidrug-resistant Pseudomonas aeruginosa clinical isolates in Japan. Compared with VIM-2, VIM-60 had two amino acid substitutions (Arg228Leu and His252Arg) and higher catalytic activities against fourth-generation cephalosporins. The genetic context for bla VIM-60 was intI1-bla VIM-60-aadA1-aacA31-qacEdeltaI-sulI on the chromosome.