Effect of vaginal fluid on adherence of type 1 piliated Escherichia coli to epithelial cells.

Colonization of the vaginal mucosa with uropathogens from fecal flora is an important step in ascending urinary tract infections (UTIs) in women. Colonization is influenced by interactions between uropathogens, vaginal fluid, and epithelial cells. In this study, vaginal fluid from 21 women was assessed for effects on adherence of type 1 piliated Escherichia coli to the A431 cell line. Adherence to cells was enhanced by all fluid specimens when tested at low fluid protein concentrations in an in vitro assay. At higher concentrations, certain specimens maintained enhanced binding whereas others resulted in diminished binding. Increases in adherence were associated with increased binding of E. coli to vaginal fluid in vitro and with higher vaginal fluid pH. These results demonstrate that vaginal fluid significantly alters the adherence of type 1 piliated E. coli to epithelial cells in vitro and, therefore, should be studied as a potential modifier in bacterial colonization and UTIs in vivo.