Fig. 1.

Relative gene expression of hla (A), sea (B), seb (C), and agrA (D) in S. aureus ATCC 33,591 grown under graded sub-inhibitory concentrations (6.25–25 µg/mL) of ETSK was analyzed by quantitative RT-PCR (qRT-PCR). Values represent the means ± SD of three independent experiments. Different letters indicate statistically significant differences (P < 0.05), while the same letters mean no significant differences (P > 0.05). Con., control, untreated S. aureus strains; hla, gene encoding α-hemolysin; sea, gene encoding staphylococcal enterotoxin A; seb, gene encoding staphylococcal enterotoxin B; agrA, gene encoding accessory gene regulator A; ETSK, Eleutheroside K