Figure 3.

Cytotoxicity elicited by the colonization of S. aureus and/or S. epidermidis after 24h (A) and 48h (B) cultivation. Cytotoxicity was quantified based on the activity of LDH released by the damaged keratinocytes. The S. aureus-colonized epidermal tissue exhibited a significantly elevated level of cytotoxicity in comparison to the S. epidermidis-colonized tissues. The S. aureus-induced cytotoxicity was attenuated by the colonization of S. epidermidis to an increasing degree as S. epidermidis was inoculated at a greater infective dose or prior to S. aureus. SE, S. epidermidis (black bars); SA, S. aureus (open bars). Light grey bars: S. epidermidis and S. aureus were inoculated simultaneously; dark grey bars: S. epidermidis was inoculated 4h prior to S. aureus. Data are presented as mean ± S.E. (n = 3-6). *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001. Tukey–Kramer Post Hoc test after One-way analysis of variance (ANOVA).