FIG 3.

Virulence factors regulated by agr are responsible for severe morbidity during nosocomial pneumonia. (A to C) Human neutrophils were exposed to 5-h culture supernatants from LAC (A), TH16 (B), and BS_4884 (C), and cell death was measured using the CellTiter assay (n = 7 to 8 donors/group) (means ± SEM). (D to F) Survival curves of antibiotic-treated C57BL/J mice infected i.n. with LAC (D), TH16 (E), and BS_4884 (F) or isogenic agr mutants of these strains (n = 6 to 11 mice/group). Statistical analysis was performed using two-way ANOVA with a Šídák posttest (A to C) and a log rank (Mantel-Cox) test (D to F). *, P < 0.05; **, P < 0.01; ****, P < 0.0001.