Clinical, microbiological, and biochemical factors in recurrent bacterial vaginosis.

Because so little is known about the pathogenesis of recurrent bacterial vaginosis (BV), a longitudinal microbiological study was conducted on 13 women with recurrent BV treated sequentially with conventional metronidazole therapy. A rapid clinical response characterized by disappearance of mal odor and an improvement in vaginal discharge occurred in 92% of 31 clinical episodes of BV, with patients no longer satisfying the composite clinical criteria for the diagnosis of BV. However, prospective evaluation of these asymptomatic women revealed profound residual biochemical and microbial abnormalities which were best evident on Gram stain and wet mount examination of vaginal secretions. Other common residual abnormalities included mild persistent elevation of vaginal pH and polyamine and fatty acid levels and the presence of clue cells in small numbers. Residual abnormalities could be quantified to create an overall symptom code which predicted recurrence, and it was found that the severity of residual abnormalities was inversely related to the time required until the next recurrence occurred. The severity and prevalence of residual abnormalities following clinically successful therapy support the concept that BV recurrence, especially when it is early, represents a relapse rather than a reinfection. This concept may have important therapeutic implications.