FIG 7.

Testing the susceptibility of biofilm-grown S. aureus JE2 antibiotic transporter mutants to norfloxacin. Biofilm disruption assays on plastic were performed with the S. aureus JE2 parental strain or the specified transposon mutant (identified by Nebraska transposon mutant library number and described in Table 1) and norfloxacin (Norflox) at 12.5 μg/ml or 25 μg/ml. Biofilms were grown for 6 h and exposed to the above treatments for 18 h, and S. aureus biofilm CFU values were determined. Each column displays the average from two biological replicates, each with three technical replicates. Error bars indicate SD. ns, not significant; values were determined by ordinary one-way ANOVA and Bonferroni multiple comparison posttest.