FIG. 4.

PIA/PNSG expression is stimulated under anaerobic conditions in six S. aureus and S. epidermidis biofilm-forming strains. Three S. aureus and three S. epidermidis biofilm-forming strains were grown under both aerobic (+) and anaerobic (−) conditions to early stationary phase (14 to 18 h) in TSB plus Glc. PIA/PNSG expression (PIA/PNSG) was detected in cell surface extracts isolated from an equal number of cells from each strain using an antibody raised against S. epidermidis PIA. Biofilm formation in a microtiter plate well is shown for each strain (Biofilm). Adhering cells are stained with safranin (red color) to facilitate visualization of the biofilm.