Drug treatments show microbiome changes in women with mixed vaginitis

A study published in Frontiers in Cellular and Infection Microbiology observed significant vaginal microbiome alterations in patients with bacterial vaginosis (BV) plus vulvovaginal candidiasis (VVC) mixed vaginitis before and after drug treatment.

Key causative bacteria were GardnerellaAtopobium and Lactobacillus. Oral metronidazole with local clotrimazole to treat BV+VVC mixed vaginitis was effective therapy in the study.1

However, a more favorable prognosis for BV+VVC mixed vaginitis might be achieved by enhancing BV treatment, according to the authors.

“The abundance of Lactobacillus in women with mixed vaginitis has a great influence on the recovery of a normal vaginal microbiome and on the prognosis, and it should be actively restored,” wrote the authors.

The study comprised 48 symptomatic patients, ranging in age from 18 to 50 (mean age 32.92 years), with a clinical diagnoses of VVC complicated by BV, who were admitted to The First Hospital of Peking University in China between January 2017 and December 2020.

Overall, 38 patients had previous VVC episodes, of whom 24 with a history of recurrent VVC (RVVC). In addition, 3 patients had previous BV episodes, while 9 patients previously had both VVC and BV.

All patients were treated with oral metronidazole (400 mg orally twice a day for 7 days) combined with local clotrimazole (500 mg intravaginally once a day on days 1, 4 and 7), then followed to assess the drug efficacy and vaginal microbiome alterations before and after therapy.

Among the cohort of 49 patients, 9 had recurrences, which was defined as BV or VVC relapsing after drug treatment

The symptoms and signs of patients with BV+VVC decreased significantly after treatment, indicating that this treatment plan can effectively relieve symptoms.

The abundance of Lactobacillus and dominant bacteria in vaginal samples changed with the remission of symptoms. The vaginal pHs were lower than 4.5 after treatment, and significantly lower than the pHs before treatment.

Overall, the BV cure rate was only 47.9%, while for VVC it was 56.3%. Such a difference (P < 0.05) indicates that this treatment may not be sufficient against bacterial vaginosis.

Further analysis of the BV treatment outcomes showed that Nugent scores increased in 4 patients, remained unchanged in 9 and decreased in 35 patients; in other words, 72.9% of patients with BV showed improvement.

However, the authors were unable to identify the microecological changes that promoted fungal relapses at a microscopic level.

The vaginal microbiome of all patients was divided into four clusters, based on correlations between the members of their microbiome at the species level.

The highest bacterial Shannon diversity index was found in cluster 3, which was mostly enriched in Prevotella, compared to cluster 1, which had the lowest diversity index and no enrichment of any single dominant genus.

“This is the first study to investigate the composition, diversity, and other characteristics of the vaginal microbiome in patients with BV+VVC mixed vaginitis before and after drug treatment,” wrote the authors. “Our results provide clues to improving the cure rate and reducing recurrences.”

Reference

1. Xiao B, A D, Qin H, et al. Correlation analysis of vaginal microbiome changes and bacterial vaginosis plus vulvovaginal candidiasis mixed vaginitis prognosis. Front Cell Infect Microbiol. Published online March 8, 2022. doi:org/10.3389/fcimb.2022.860589