Biofilm-Forming Staphylococcus epidermidis Expressing Vancomycin Resistance Early after Adhesion to a Metal Surface

Figure 4

Changes in VCC with changes in the VCM concentration administered at various time points of biofilm formation. No significant changes were noted in the viable cell count in biofilm after 20-hour culture among the VCM concentrations in the immediate, 2 hr, or 4 hr group ((a), (b), (c)). VCC was 10⁷–10⁵ CFU when the VCM concentration was 0–8 μg/mL in the immediate, 2 hr, and 4 hr groups. The count was only 10³ CFU at 16 μg/mL and 0–10 CFU at 32 μg/mL or higher in the immediate and 2 hr groups. In the 4 hr group, the count was 10² CFU at 32 μg/mL or higher and only 10 CFU at 64 μg/mL or higher. In the 8 hr group, the count was 10⁷–10⁵ CFU after 20-hour culture in the presence of VCM at 16 μg/mL or lower, showing no effect of VCM, and it significantly decreased at 32 μg/mL or higher (d), but the count was still high (2.4 × 10⁴ CFU) even at the highest VCM concentration (1,024 μg/mL). Values represent mean and error bars indicate SD (). versus control.

(a)

(b)

(c)

(d)