Studies of introital colonization in women with recurrent urinary infections. VIII. The role of bacterial interference.

The non-pathogenic aerobic bacteria in 97 quantitative introital cultures from 11 women with documented recurrent bacteriuria were compared statistically to those in 100 quantitative introital cultures from 10 control women with no history of bacteriuria. The colonization incidence of the non-pathogenic organisms was not statistically different for the 2 groups, except for gamma hemolytic Streptococcus (p equals 0.002). No strongly significant correlations were demonstrated between the colonization incidence of Enterobacteriaceae or enterococci and the colonization incidence of the common non-pathogenic organisms, when analyzed for the bacteriuric and control groups or when analyzed for the individual cultures of each subject. A quantitative analysis of the 197 individual cultures failed to establish correlations between the presence of the common non-pathogenic organisms and Enterobacteriaceae or enterococci. The susceptibility of the vaginal introitus to colonization by urinary pathogens cannot be explained by interrelationships between these pathogens and the normal aerobic vaginal flora.