Intestinal Bacteroides vulgatus showing resistance to metals
Aline Ignacio, Viviane Nakano, Mario Julio Avila-Campos
Background: Bacteroidaceae species are predominant in human large intestine, particularly in the colon. These microorganisms are able to develop resistance to several antimicrobial drugs. Aim: The aim was to determine the resistance profile and presence of genes encoding resistance to metals in intestinal Bacteroidaceae from children and calves. Methods: A total of 44 strains were tested. Antimicrobial resistance and presence of resistance genes were evaluated. Resistant strains were submitted to plasmid cure, and the susceptibility was tested again. Results: Most of the tested strains were resistance to metals and a strain of Bacteroides vulgatus (human origin) showed 3.0 kb and 5.0 kb plasmids and a strain of B. vulgatus (animal origin) showed a 4.0 kb plasmid in which the presence of genes czcA, czcB, and czcC was observed. Resistant strains lost the plasmids and resistance to metals was decreased. Conclusions: The presence of genes might be any association with the cadmium resistance. Further studies to characterize the resistance mechanisms or CzcCBA efflux system in Bacteroidaceae species are necessary.