Identification of a Novel Metallo-β-Lactamase, VAM-1, in a Foodborne Vibrio alginolyticus Isolate from China

A multidrug-resistant Vibrio alginolyticus isolate recovered from a shrimp sample with reduced carbapenem susceptibility produced a novel metallo-beta-lactamase (MBL), VAM-1. That carbapenemase shared 67% to 70% amino acid identity with several VMB family subclass B1 MBLs, which were recently reported among some marine bacteria including Vibrio, Glaciecola, and Thalassomonas. The bla(VAM-1) gene was located in a novel conjugative plasmid, namely, pC1579, and multiple copies of bla(VAM-1) via an unusual mechanism of gene amplification were detected in pC1579. These findings underline the emergence of marine organisms acting as natural reservoirs for MBL genes and the importance of continuous bacterial antibiotic resistance surveillance.