High recurrence rates of bacterial vaginosis over the course of 12 months after oral metronidazole therapy and factors associated with recurrence

Background. We wished to determine recurrences of bacterial vaginosis (BV) after treatment over the course of 12 months and to establish factors associated with recurrence. Methods. Women with symptomatic BV ( a Nugent score [NS] of 7 - 10 or of 4 - 6 with >= 3 Amsel criteria) were enrolled. BV was treated with 400 mg of oral metronidazole twice a day for 7 days. Participants completed a questionnaire and vaginal swabs were collected at 1, 3, 6, and 12 months; the study end point was an NS of 7 - 10. Results. A total of 121 (87%) women with an NS of 7 - 10 and 18 (13%) with an NS of 4 - 6 and >= 3 Amsel criteria were enrolled; 130 (94%) returned >= 1 vaginal samples. Sixty-eight women (58% [95% confidence interval {CI}, 49% - 66%]) had a recurrence of BV ( NS 7 - 10), and 84 (69% [ 95% CI, 61% - 77%]) had a recurrence of abnormal vaginal flora ( NS 4 - 10) by 12 months. A past history of BV, a regular sex partner throughout the study, and female sex partners were significantly associated with recurrence of BV and abnormal vaginal flora by multivariate analysis; the use of hormonal contraception had a negative association with recurrence. Conclusion. Current recommended treatment is not preventing the recurrence of BV or abnormal vaginal flora in the majority of women; factors associated with recurrence support a possible role for sexual transmission in the pathogenesis of recurrent BV.