Sfh-1, a subclass B2 metallo-β-lactamase from a Serratia fonticola environmental isolate

An environmental isolate of Serratia fonticola resistant to carbapenems was shown to contain a genetic determinant encoding a metallo-beta-lactamase of the subclass B2. The Sfh-I enzyme exhibits some divergence from the previously characterized enzymes of this subclass. This is the first example of a naturally occurring metallo-beta-lactamase in Enterobacteriaceae.