FIG. 6.

Alteration of survival of S. aureus in human blood and in U937 monocytic cells due to absence of luxS or kdpDE. (A) Rates of survival for the S. aureus NCTC8325 wild type (WT), the luxS mutant (SX1), the luxS mutant with a plasmid containing luxS (SX2), the luxS mutant with 39 nM AI-2 (SX1 + AI-2), the kdpDE mutant (SX8), and the kdpDE mutant with a plasmid containing kdpDE (SX9). The strains were incubated in heparinized human blood, and the results are from five separate blood donors. (B) S. aureus survival when it was cultured with U937 monocytic cells. The percentage of S. aureus CFU that survived was determined as described in Materials and Methods.