RNA-Seq for identification of differntially expressed genes by VxrB(D78E) overexpression

Bactericidal antibiotics are powerful drugs because they not only inhibit essential bacterial functions, but convert them into toxic processes. Many bacteria are remarkably tolerant against antibiotics, due to inducible damage repair responses. How these responses promote whole population tolerance in important human pathogens is poorly understood. The two-component system VxrAB of the diarrheal pathogen Vibrio cholerae, a model system for tolerance against cell wall damaging (e.g., beta-lactam) antibiotics, is required for high-level beta-lactam tolerance. Here, we report the mechanism of VxrAB-mediated survival. We find that -lactam antibiotics inappropriately induce the Fur-regulated iron starvation response, causing an increase in intracellular free iron and colateral oxidative damage. VxrAB reduces antibiotic-induced toxic influx of Fe by downregulating iron importers and induces cell wall synthesis functions to counteract cell wall damage. Our results highlight the complex responses elicited by antibiotics and suggest that the ability to counteract diverse stresses promotes high-level antibiotic tolerance.