FIG. 4.

Internalization in the presence of externally added Eap. (a) Confluent layers of fibroblast cells were inoculated with strains Newman and mAH12 with or without Eap present and incubated at 37°C for 2 h. To quantify internalization, wells were (after being washed) further incubated with lysostaphin to kill the extracellular bacteria. Cells were detached and lysed, and bacterial viable counts were determined. (b) Clinical isolates U35 and L12 in the presence or absence of Eap. The bars show the mean CFU in four experiments for Newman and mAH12 and six experiments for clinical isolates U35 and L12. Error bars indicate standard deviation. Statistical differences were determined by Student's t test, *, P < 0.05; **, P < 0.01.