Fig. 7

Persister cells on biofilms. Strains USA300 LAC, msaABCR deletion mutant, and the complementation were allowed to form biofilm on intravenous catheters for 24 h. Biofilm were then exposed to high concentration of antibiotics. a. no antibiotic control, b. daptomycin (20 μg/ml, 20× MIC), c. vancomycin (12.5 μg/ml, 20× MIC), d. rifampicin (4.8 μg/ml, 80× MIC), e. linezolid (100 μg/ml, 20× MIC), and f. gentamicin (100 μg/ml, 20× MIC). The arrow in the no antibiotic control (a.) represents the starting point for the antibiotic treatment in the tests. These results represent the means of three independent experiments performed in triplicate. Error bars represent SE. Student’s t-test and one-way ANOVA (OriginPro) followed by Tukey’s test was used to compare the results of the wild-type to mutants at respective designated time points (* p-value <0.05, ** p-value <0.005)