ZHO-1, an intrinsic MBL from the environmental Gram-negative species Zhongshania aliphaticivorans.

OBJECTIVES: Our aim was to characterize the putative MBL of the environmental strain Zhongshania aliphaticivorans isolated from a marine environment.

METHODS: The putative MBL was identified in silico using the NCBI database. The β-lactamase gene was cloned into different Escherichia coli backgrounds. Kinetic parameters were determined using the purified enzyme.

RESULTS: The enzyme named ZHO-1 shared 51% amino acid identity with the acquired class B carbapenemases IMP-1, KHM-1 and DIM-1. Expression of the blaZHO-1 gene in a susceptible E. coli resulted in a carbapenemase phenotype. Kinetic parameters determined from purified ZHO-1 enzyme showed that it had significant hydrolytic activity against most β-lactams including penicillins, cephalosporins and carbapenems, with the exception of aztreonam and cefepime.

CONCLUSIONS: This study adds to the knowledge regarding environmental species as a reservoir of possible clinically relevant MBLs.