FIG 2.
Sensitivity of USA300 and USA300 farR::ΦNE to the bactericidal activity of 100 μM linoleic acid (LA). (A) USA300 or USA300 farR::ΦNE challenge cells were grown to mid-exponential phase in TSB or in TSB–20 μM linoleic acid and then diluted to 106 CFU/ml in TSB containing 100 μM linoleic acid. Viability was monitored at hourly intervals. (B) USA300 farR::ΦNE was complemented with empty pLI50 vector or pLIfarR and assayed for viability in 100 μM linoleic acid after initial growth in TSB–20 μM linoleic acid. All data points represent the means ± standard deviations of viability determinations from quadruplicate cultures. Significant differences in viability at each time point were determined by an unpaired one-tailed Student's t test (*, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, nonsignificant).