The contribution of tellurite resistance genes to the fitness of Escherichia coli uropathogenic strains

The presence of tellurite resistance gene operons has been reported in several human pathogens despite the fact that tellurium, as well as its soluble salts, are both rare in nature and are no longer in use as antimicrobial agents. We have introduced the cloned terWZA-F genes from an uropathogenic Escherichia coli isolate into another clinical E. coli isolate that was shown to be ter-gene free. The presence of the introduced genes increased the level of potassium tellurite resistance, as well as the level of resistance to oxidative stress mediated by hydrogen peroxide; and prolonged the ability of particular strains to survive in macrophages. We therefore propose that the contribution of tellurite resistance genes to oxidative stress resistance in bacteria is at least one reason for their presence in the genomes of a broad range of pathogenic microorganisms.