Molecular diversity of chromosomal metallo-β-lactamase genes in Elizabethkingia genus.

Abstract

Elizabethkingia genus is an opportunistic life-threatening pathogen with intrinsic multidrug-resistant phenotype. It is the only known microorganism with multi-chromosome-borne metallo-β-lactamase genes. To determine the diversity and distribution of MBLs Bla and Bla in this genus, we applied comprehensive bioinformatic screening in 109 available Elizabethkingia genomes. A total of 23 and 32 novel Bla and Bla variants were found in Elizabethkingia spp., 12 and 15 clusters were assigned in these Bla and Bla based on the amino acid identities and phylogenetic studies. Clustering of some variants did not conform to species-specific clades which suggested potential inter-species dissemination of MBLs genes among Elizabethkingia species. Cloning of representative bla and bla into E. coli DH5α resulted in increased and diverse MICs to most β-lactams, including cephalosporins, carbapenems, and β-lactams-inhibitors. This study extends the database of class B carbapenemases, emphasizing the diversity of different MBLs genes in the genus Elizabethkingia, which may represent potential reservoirs of acquired MBLs.