The vaginal bacterial communities of Japanese women resemble those of women in other racial groups

Abstract

To determine whether different racial groups shared common types of vaginal microbiota, we characterized the composition and structure of vaginal bacterial communities in asymptomatic and apparently healthy Japanese women in Tokyo, Japan, and compared them with those of White and Black women from North America. The composition of vaginal communities was compared based on community profiles of terminal restriction fragments of 16S rRNA genes and phylogenetic analysis of cloned 16S rRNA gene sequences of the numerically dominant bacterial populations. The types of vaginal communities found in Japanese women were similar to those of Black and White women. As with White and Black women, most vaginal communities were dominated by lactobacilli, and only four species of Lactobacillus (Lactobacillus iners, Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus gasseri) were commonly found. Communities dominated by multiple species of lactobacilli were common in Japanese and White women, but rare in Black women. The incidence, in Japanese women, of vaginal communities with several non-Lactobacillus species at moderately high frequencies was intermediate between Black women and White women. The limited number of community types found among women in different ethnic groups suggests that host genetic factors, including the innate and adaptive immune systems, may be more important in determining the species composition of vaginal bacterial communities than are cultural and behavioral differences.

Figure 1

Dendrogram constructed by cluster analysis (Ward’s method) based on similarity in the T-RFLP profiles among vaginal microbial communities in Japanese, White, and Black women. The samples from White, Black and Japanese women are designated with an open circle, closed circle and red triangle, respectively. The red line shows the grouping baseline. Big triangles labeled with various colors indicate clusters. The clusters are designated with a “C” followed by a number. Asterisks indicate the samples from each group used to construct clone libraries of 16S rRNA genes.

Figure 2

Two dimensional scatter plot constructed by multidimensional-scaling (MDS) analysis based on similarity in T-RFLP profiles among vaginal microbial communities in Japanese, White and Black women. The samples from White, Black and Japanese women are designated with green, black and red dots, respectively.

Figure 3

The rank abundances of vaginal communities found in White, Black and Japanese women. Each column was designated with each group (community types; see Tables 1–3). The proportion of Black and White women of North America, and Japanese women are shown as dark gray, gray and light gray in each column, respectively.