Vaginal microbiome: rethinking health and disease

Abstract

Vaginal microbiota form a mutually beneficial relationship with their host and have a major impact on health and disease. In recent years our understanding of vaginal bacterial community composition and structure has significantly broadened as a result of investigators using cultivation-independent methods based on the analysis of 16S ribosomal RNA (rRNA) gene sequences. In asymptomatic, otherwise healthy women, several kinds of vaginal microbiota exist, the majority often dominated by species of Lactobacillus, while others are composed of a diverse array of anaerobic microorganisms. Bacterial vaginosis is the most common vaginal condition and is vaguely characterized as the disruption of the equilibrium of the normal vaginal microbiota. A better understanding of normal and healthy vaginal ecosystems that is based on their true function and not simply on their composition would help better define health and further improve disease diagnostics as well as the development of more personalized regimens to promote health and treat diseases.

Figure 1

Heatmap of percentage abundance of microbial taxa found in the vaginal microbial communities of 394 reproductive-age women. (A) Complete linkage clustering of samples based on species composition and abundance in communities defining five community state types (CST I–V). (B) Nugent scores and pH measurements for each of the 394 samples. [Adapted from (86)]

Figure 2

Whole genome comparative analysis of G. vaginalis using Blast Score Ratio Analysis. A protein match between two genomes is represented by a point plotted using the genomic coordinate of both matched proteins as X and Y coordinates. The level of protein sequence similarity is represented by the color of the points (see scale on right). (A) High degree of protein similarity and synteny is observed between G. vaginalis strains HMP9231 and ATCC 14019. (B) Lack of synteny and low degree of protein similarity is observed between G. vaginalis strains HMP9231 and 409-05. The blue bar highlights a set of syntenic genes that are unique to G. vaginalis HMP9231 and are not present in the other two genomes.

Figure 3

Temporal dynamics of vaginal bacterial communities in women sampled twice-weekly over 16 weeks. Interpolated bar plot of phylotypes relative abundance for four subjects (A–D) with different community dynamics profiles. Color key for each phylotype is shown on top each graph. Vertical lines represents sampling time points.