Bacillus subtilis as a platform for molecular characterisation of regulatory mechanisms of Enterococcus faecalis resistance against cell wall antibiotics.

摘要: To combat antibiotic resistance of Enterococcus faecalis, a better understanding the molecular mechanisms, particularly detection, signal transduction and gene regulation is needed. Because studies in this bacterium can be challenging, we aimed at exploiting genetically highly tractable Gram-positive model organism Bacillus subtilis as heterologous host. Two fundamentally different regulators E. faecalis against cell wall antibiotics, bacitracin sensor BcrR vancomycin-sensing two-component system VanSB-VanRB, were produced B. their functions monitored using target promoters fused to reporter genes (lacZ luxABCDE). The BcrR-BcrAB was fully functional subtilis, both regarding bcrAB expression mediated by transporter BcrAB. Removal intrinsic increased sensitivity system. lacZ luxABCDE reporters found offer sensitive detection promoter induction on solid media, which useful for screening large mutant libraries. VanSB-VanRB displayed gradual dose-response behaviour vancomycin, but only when low levels cell. Taken together, our data show that well-suited host characterization regulatory systems controlling active compounds faecalis. Importantly, facilitates careful adjustment genetic background required full functionality introduced regulators.