The tellurite resistance gene cluster of pathogenic bacteria and its effect on oxidative stress response.

ABSTRACT

Tellurite resistance gene clusters have been identified in numerous pathogenic bacteria, including clinical isolates of Escherichia coli. The rareness of tellurium in host organisms and the noncontaminated environment raises a question about the true functionality of tellurite resistance gene clusters in pathogenesis and their possible contribution to bacterial fitness. The study aims to point out the beneficial effects of the tellurite resistance gene cluster of pathogenic bacteria to survive in ROS-rich environments. Here, we analysed the bacterial response to oxidative stress conditions with and without tellurite resistance gene clusters, which are composed of terWY1XY2Y3 and terZABCDEF genes. By measuring the levels of protein carbonylation, lipid peroxidation, and expression changes of oxidative stress genes upon oxidative stress, we propose a tellurite resistance gene cluster contribution to the elimination of oxidative damage, potentially increasing fitness and resistance to reactive oxygen species during macrophage attack. We have shown a different beneficial effect of various truncated versions of the tellurite resistance gene cluster on cell survival. The terBCDEF genes increased the survival of E. coli strain MC4100 by 13.21%, terW and terZABCDEF by 10.09%, and terWY1XY2Y3 and terZABCDEF by 25.57%, respectively. The ability to survive tellurite treatment is the most significant at 44.8% in wild clinical strain KL53 compared to laboratory strain E. coli MC4100 due to a complete wild-type plasmid presence.