FIG 1.

Virulence profile of HA-MRSA. (A) Growth curves of S. aureus strains LAC, TH16, and BS_4884 (n = 3) (means ± standard errors of the means [SEM]). (B) Strains were cross-streaked against RN4220 on sheep blood agar plates. (C) Immunoblot probing with antibodies against four different leukotoxins, after LAC, TH16, and BS_4884 had been grown in TSB for 5 h. (D) Human neutrophils were exposed to various concentrations of culture supernatants isolated after 5 h, and cell death was measured using the CellTiter assay (n = 8 donors) (means ± SEM). (E) Survival curve of C57BL/6J mice challenged intranasally with 4 × 10⁸ CFU (n = 8 mice/group). Statistical analysis was performed using two-way analysis of variance (ANOVA) with Dunnett’s posttest (D) or a log rank (Mantel-Cox) test (E). *, P < 0.05; **, P < 0.01; ****, P < 0.0001.