Figure 2

β-Galactosidase liquid assay: effect of non-aureus staphylococci (NAS) on agr induction of Staphylococcus aureus over time. (A) The β-galactosidase activity of Staphylococcus aureus rnaIII::lacZ reporter strain SH101F7 was monitored for 4 h growing alone (negative control) in TSB, or in co-culture (1:1) with Staphylococcus chromogenes (n = 34), Staphylococcus epidermidis (n = 11), Staphylococcus simulans (n = 14), and Staphylococcus schleiferi strain 2898 (positive control). (B) The rnaIII expression of NAS isolates affected (hatched bars) or not (solid bars) by NAS in vitro growth inhibition of S. aureus [27]. Each bar represents the least square means of three biological replicates and the error bars represent the standard deviation.