Analysis of Genetic VapC Profiles from the Toxin-Antitoxin Type II VapBC Modules among Pathogenic, Intermediate, and Non-Pathogenic .

Pathogenic spp. is the etiological agent of leptospirosis. The high diversity among species provides an array to look for important mediators involved in pathogenesis. Toxin-antitoxin (TA) systems represent an important survival mechanism on stress conditions. BC modules have been found in nearly one thousand genomes corresponding to about 40% of known TAs. In the present study, we investigated TA profiles of some strains of using a TA database and compared them through protein alignment of VapC toxin sequences among spp. genomes. Our analysis identified significant differences in the number of putative BC modules distributed in pathogenic, saprophytic, and intermediate strains: four in , three in , eight in , and 15 in . The VapC toxins show low identity among amino acid sequences within the species. Some VapC toxins appear to be exclusively conserved in unique species, others appear to be conserved among pathogenic or saprophytic strains, and some appear to be distributed randomly. The data shown here indicate that these modules evolved in a very complex manner, which highlights the strong need to identify and characterize new TAs as well as to understand their regulation networks and the possible roles of TA systems in pathogenic bacteria.