Figure 3. Vancomycin tethered titanium discs prevented the emergence of resistance to rifampicin.
Vancomycin tethered and control discs were seeded with 2×106, 2×107 or 2×108 CFU in presence of a suprainhibitory concentration of rifampicin (0.03 mg/L). Following centrifugation and incubation for 18 h, adhering bacteria were detected by resazurin assay and the discs were imaged by confocal laser scanning microscopy. Control discs inoculated with lower inocula were free of live cells, however, S. aureus grew in wells inoculated with 2×108 CFU. A Resorufin assay: biofilm-forming bacteria reduce resazurin to resorufin on control discs inoculated with 2×108 CFU/well, whereas vancomycin tethered discs prevented biofilm formation when inoculated with the same inoculum. B Confocal laser scanning microscopy shows that the surface of the control discs inoculated with 2×108 CFU/well are colonized with a mixture of live (green, labeled by Syto9) and dead (yellow, co-labeled by Syto9 and propidium iodide) bacteria.