Fig 2.

Induction of trfA mRNA levels by cell wall-active antibiotics. Steady-state mRNA levels of trfA and hu (control) were determined by qRT-PCR and normalized to 16S rRNA. The mRNA levels of antibiotic-treated bacteria were compared to that of strain ISP794 in the absence of antibiotic addition. oxa, oxacillin; van, vancomycin; tec, teicoplanin; D-cyclo, d-cycloserine; Cip, ciprofloxacin. The values reported represent the means and SEM of at least three independent experiments. *, results significantly different by Student's two-tailed t test (P < 0.05). Note the absence of trfA induction by the non-cell-wall-targeting drug ciprofloxacin.