ABSTRACT
A chromosome-encoded β-lactamase gene from Shewanella algae clinical isolate KB-1 was cloned and expressed in Escherichia coli. It encoded the Ambler class D enzyme OXA-55, sharing less than 55% identity with any other oxacillinases. Although conferring a narrow-spectrum β-lactam resistance phenotype, OXA-55 had carbapenem-hydrolyzing activity that mirrored the reduced susceptibility to imipenem observed in S. algae KB-1. Very similar oxacillinases were found in other S. algae isolates.
Genetic and Biochemical Characterization of a Chromosome-Encoded Carbapenem-Hydrolyzing Ambler Class D β-Lactamase from Shewanella algae
