NDM-12, a Novel New Delhi Metallo-β-Lactamase Variant from a Carbapenem-Resistant Escherichia coli Clinical Isolate in Nepal

Abstract

A novel New Delhi metallo-β-lactamase variant, NDM-12, was identified in a carbapenem-resistant Escherichia coli clinical isolate obtained from a urine sample from a patient in Nepal. NDM-12 differed from NDM-1 by two amino acid substitutions (M154L and G222D). The enzymatic activities of NDM-12 against β-lactams were similar to those of NDM-1, although NDM-12 showed lower kcat/Km ratios for all β-lactams tested except doripenem. The blaNDM-12 gene was located in a plasmid of 160 kb.