FIG. 3.

Relative association and invasion frequencies of different flagellar mutants with HBMEC compared to those of the wild-type strain. The assays were carried out with and without centrifugation of bacteria. The fliI, flhDC, and fliC mutants exhibited statistically significant (P < 0.05) decreases in the relative association and invasion frequencies, while the cheW mutant displayed no defects in association and invasion. The bars indicate the means of two or three independent experiments, and the error bars indicate the standard deviations. Wt, wild type.