Adherence of bacteria to vaginal epithelial cells at various times in the menstrual cycle.

Adherence of vaginal isolates of Escherichia coli, Lactobacillus species, group B streptococci, Gardnerella vaginalis and Neisseria gonorrhoeae to exfoliated vaginal epithelial cells was studied in 10 healthy, sexually active medical students. Studies were done pre- and postmenstrually and at midcycle for two consecutive menstrual cycles. The mean number of adherent bacteria per vaginal epithelial cell (range) was 3.4 (0 to 14) for E. coli, 60.5 (12 to 152) for Lactobacillus species, 54.8 (21 to 76) for group B streptococci, 67.4 (15 to 161) for G. vaginalis, and 58.9 (15 to 186) diplococci for N. gonorrhoeae. Adherence of G. vaginalis increased with increasing acidity of the test medium (pH 4 to 8). There were no significant differences in adherence to vaginal epithelial cells obtained at the various times in the menstrual cycle for any of the organisms (p greater than 0.05). The pattern and extent of adherence among the women was similar for each organism. In this in vitro model, adherence characteristics did not vary with the menstrual cycle.