Role of conjugative transposons of the SXT/R391 family in mutagenesis in Proteus mirabilis clinical isolates

Abstract

Proteus mirabilis is a bacterium that causes catheter-associated hospital infections (CAUTIs) and is highly relevant when catheterization becomes longer. Given that this bacterium is naturally sensitive to beta lactams, the emergence of resistant strains suggested the existence of horizontal gene transfer mechanisms, which led to the identification of the integrative conjugative elements (ICEs) of the SXT / R391 family, already described in Vibrio cholerae. ICEs are mobile genetic elements that control their own excision and integration into the genome of organisms, and have variable regions that allow recombination processes, enabling the incorporation of resistance genes. In addition, these elements have been shown to carry genes related to DNA repair mechanisms, such as the rumAB operon, which encodes a Y family polymerase, which has a higher error rate compared to replicative polymerases. Previous studies from our laboratory have verified that the presence of this element does not alter the rate of spontaneous mutation. Taking this as a starting point, our hypothesis was that the presence of ICEs may influence DNA-induced mutagenesis. In this project, we propose a characterization of rumAB expression after DNA damage, and analysis of their role in mutagenesis, strains carrying or not the ICE, when exposed to agents that cause DNA damage. (AU)