Figure 1 Estimation of biofilm biomass for 32 clinical S. aureus strains by crystal violet (CV) staining and viable cells analysis by colony counting (log10 CFU/mL). The Mann-Whitney test showed statistical significance in the amount of biofilm analyzed by CV test and CFU method (P<0.0001). *0.658=the cut-off for the moderate and strong biofilm mass producer; 19*, strain isolated from patient with S. aureus infection; red point, qualitative biofilm biomass test (CV); green point, the quantitative in vitro biofilm test (log10 CFU/mL).