[Illumina sequencing 16S rRNA tagging reveals diverse vaginal microbiomes associated with bacterial vaginosis]

To analyze and compare vaginal microbiomes in healthy women at child-bearing ages and patients with bacterial vaginosis (BV).

A total of 74 vaginal swabs of the vaginal fornix were collected from 37 BV patients and 37 healthy women. BV status was assessed according to Amsels clinical criteria for all the subjects and confirmed using Gram-stain criteria (Nugent scores). Genomic DNA of the samples was extracted for amplifying the 16S rRNA V6 hypervariable region by PCR and pyrosequencing by Illumina. BIPES, UCHIME, TSC and GAST were employed to analyze the information of the species from the samples.

Lactobacillus was the predominant species in healthy women (more than 95%), including mainly L. iners and L. crispatus, with a small quantity of Gardnerella, Granulicatella, Streptococcus, Prevotella, Escherichia and other genus. The α diversity was significantly increased in 30 BV patients (P<0.001), and β diversity also changed obviously shown by decreased Lactobacillus (varying from 45% to 1%, consisting mainly of L. iners) or even absence Lactobacillus in 6 cases, with increased relative abundance of Gardnerella, Prevotella, Granulicatella, Anaerococcus, Parvimonas, Peptoniphilus.harei, Peptostreptococcus, and Dialister. Different from previous data, 7 BV cases showed a predominance of the rare species L.gasseri and L.acidophilus (75% to 50%).

Lactobacillus is the predominant vaginal species in healthy women (mainly L. iners and L. crispatus) co-existing with many other bacteria and a variety of microorganisms. Lactobacillus is significantly decreased and even absent in most of BV patients, and some cases show the predominance of the rare species L.gasseri and L.acidophilus.