Fig. (3) Clinical isolates of S. aureus growing in modified CRA (without sucrose) [A] and modified CRA containing sub-MICs of rifampicin (0.002 or 0.004 µg/mL) [B]. Identification of the isolates: C10, C12, C39, C40 and C50. Biofilm negative: spots with smooth appearance. Biofilm positive: spots with rough appearance.