FIG 6.

Exposure to P. aeruginosa PA14 exoproducts does not alter expression of a subset of S. aureus Newman antibiotic transporters. Quantitative reverse transcription-PCR (qRT-PCR) assays were performed to measure the expression of four S. aureus antibiotic transporters (mdeA, mepA, sdrM, and norA) in S. aureus Newman biofilm populations exposed to norfloxacin (Norflox) at 10 μg/ml, supernatants from wild-type P. aeruginosa PA14 supernatant (Pa WT sup) and the ΔlasR deletion mutant (Pa ΔlasR sup), or medium alone. Expression was normalized to S. aureus rpoB and is presented as relative to expression in medium alone. Each column displays the average from three biological replicates, each with three technical replicates. Error bars indicate SD. None of the above treatment conditions resulted in significant differences in expression for any of the genes tested relative to expression in medium alone by multiple Student t tests and the Holm-Šidák method for correcting multiple comparisons.