Intravaginal microbial flora by the 16S rRNA gene sequencing

Objective: Conventional diagnosis of bacterial vaginosis contains some controversial points. To understand accurately the relationship between clinical stages and the microbiotas, the intravaginal microbial flora was analyzed by the clone library method.

Study design: Vaginal fluid samples from 31 patients were examined. Lactobacillary grade, Nugent score, culture-based method, and clone library analysis using the 16SrRNA gene sequencing were performed and were compared with each other.

Results: Patients were categorized by Lactobacillary grade as I (normal) (n = 6), II (intermediate) (n = 11), and III (bacterial vaginosis) (n = 14). The clone library analysis detected 36 bacterial genera and 60 species from all 31 samples. A principal component analysis of the microbial proportions revealed a novel classification, which suggested the significance of the relative ratio of Lactobacillus iners, Atopobium vaginae and anaerobes in bacterial vaginosis.

Conclusion: Clone library analysis in combination with the conventional method provides substantial information for diagnosis of bacterial vaginosis.