Utilization of PCR to Characterize Vaginal Flora in a Longitudinal Study of Recurrent Bacterial Vaginosis
Methods: We performed a longitudinal study on symptomatic BV patients, obtaining vaginal specimens at 3 visits: initial diagnosis, 10-14 days and ~1 month later. BV was diagnosed based on signs and symptoms (Amsel’s criteria) and Nugent score (Gram-stained vaginal smears). DNA was extracted from vaginal specimens and analyzed by real-time PCR to quantify the presence of BV-associated microbes and commensal lactobacillus species.
Results: Initial diagnosis of BV by either Amsel’s criteria or Nugent score was strongly correlated with the presence and quantity of Gardnerella vaginalis, Atopobium vaginae, BVAB2 and Megasphaera and reduced presence of commensal lactobacillus species. When evaluated 10-14 days later, treatment was successful in 78/82 patients (95%) and was associated with the eradication of Megasphaera type 1 in 54/55 (98%) and type 2 in 21/21 (100%) patients. In contrast, G. vaginalis, A. vaginae and BVAB2 persisted in 54/75 (72%), 36/69 (52%) and 19/58 (33%) patients, respectively, although their median concentrations decreased by ~3 logs. Frequency of colonization with the commensal lactobacillus species L. crispatus, L. gasseri and L. jensenii all increased after treatment; from 17% to 32%, 7.7% to 12% and 10% to 25%, respectively. Twenty-nine patients (37%) would go on to experience recurrent disease at their 3rd visit, ~ 1 month after diagnosis. However, neither persistence of BV-associated microbes nor colonization with commensal lactobacillus species after treatment was associated with disease recurrence.
Conclusion: Successful treatment of BV is associated with profound changes in the vaginal flora that can be characterized by PCR. Recurrent disease in this population was not associated with treatment failure and the recovery of commensal lactobacillus species was not protective. Future studies will evaluate additional factors contributing to disease recurrence.
Medical Diagnostic Laboratories: Employee, Salary
M. Adelson, Medical Diagnostic Laboratories: Employee, Salary
E. Mordechai, Medical Diagnostic Laboratories: Employee, Salary
J. D. Sobel, Medical Diagnostic Laboratories: Board Member, Consulting fee
S. Gygax, Medical Diagnostic Laboratories: Employee, Salary