Phenotypic characterization of S. aureus rlmQ mutant. (A–C) Growth of the WT strain and the mutant inactivated for rlmQ (rlmQ−) was compared under different media and temperature conditions. Bacterial growth was measured during 24 h in BHI medium at 37°C (A), 42°C (B), and in RPMI medium at 37°C (C), n = 2–6. (D) Biofilm was quantified by crystal violet staining of the extracellular matrix after 24 h of culture in BHI medium, n = 8. (E) Bacterial supernatant cytotoxicity was quantified by measuring propidium iodide (PI) incorporation into C5aR1-transfected U937 monocytes, n = 7. Mann–Whitney tests performed: (*) P-value < 0.05, (**) P-value < 0.01, (***) P-value < 0.001. (F) Mutation rate of protein sequences from 301 clinical strains was estimated with a ratio: number of missense mutations divided by sequence match length.
