RexAB promotes the survival of < em > Staphylococcus aureus < /em > exposed to multiple classes of antibiotics

Antimicrob Agents Chemother. 2021 Jul 26:AAC0059421. doi: 10.1128/AAC.00594-21. Online ahead of print.ABSTRACTAntibiotics inhibit essential bacterial processes, resulting in arrest of growth and in some cases cell death. Many antibiotics are also reported to trigger endogenous production of reactive oxygen species (ROS), which damage DNA, leading to induction of the mutagenic SOS response associated with the emergence of drug resistance. However, the type of DNA damage that arises and how this triggers the SOS response is largely unclear. We found that several different classes of antibiotic triggered dose-dependent induction of the SOS response in Staphylococcus aureus, indicative of DNA damage, including some bacteriostatic drugs. The SOS response was heterogenous and varied in magnitude between strains and antibiotics. However, in many cases, full induction of the SOS response was dependent upon the RexAB helicase/nuclease complex, which processes DNA double strand breaks to produce single-stranded DNA and facilitate RecA nucleoprotein filament formation. The importance of RexAB in repair of DNA was confirmed by measuring bacterial survival during antibiotic exposure, with most drugs having significantly greater bactericidal activity against rexB mutants relative to wild type strains. For some, but not all antibiotics there was no difference in bactericidal activity between wild type and rexB mutant under anaerobic conditions, indicative of a role for reactive oxygen speci...
Source: Antimicrobial Agents and Chemotherapy - Category: Microbiology Authors: Source Type: research