A novel type I toxin-antitoxin system modulates persister cell formation in Staphylococcus aureus.

A novel type I toxin-antitoxin system modulates persister cell formation in Staphylococcus aureus. Int J Med Microbiol. 2020 Jan 17;:151400 Authors: Habib G, Zhu J, Sun B Abstract A plethora of toxin-antitoxin systems exist in bacteria and has multilateral roles in bacterial pathogenesis and virulence. Toxin-antitoxin systems have been involved in persister cell formation in Escherichia coli and Mycobacterium but have not been reported to be associated with Staphylococcus aureus persistence. Persistence is the ability of bacterial cells to tolerate unfavorable conditions and multiple stresses. There are less known and more unknown factors that either alleviate or aggravate bacterial persistence phenomenon. For the first time, we reported a new chromosomally encoded tripartite toxin-antitoxin system and its role in S. aureus persister cell formation. The toxin gene is bacteriostatic in action and counterbalanced by antitoxin RNA that could basepair with the toxin mRNA and formed a duplex. The transcriptional regulator positively regulates the toxin expression under certain stress conditions. The toxin ectopic induction increased S. aureus susceptibility to norfloxacin, ciprofloxacin, and ofloxacin. Whole-genome RNA sequencing revealed that MDR efflux pump norA is significantly down-regulated by toxin ectopic induction. The deletion of norA from S. aureus genome reduced resistance toward ciprofloxacin, norfloxacin, and ofloxacin, as we...
Source: International Journal of Medical Microbiology - Category: Microbiology Authors: Tags: Int J Med Microbiol Source Type: research