Differences in the vaginal lactobacilli of postmenopausal women and influence of rectal lactobacilli

This study was undertaken to characterize the Lactobacillus spp. dominating the vaginal microbiota of healthy postmenopausal women and to determine the possible influence of rectal lactobacilli.

Sixty postmenopausal women aged 55-65 years without clinical signs of vaginal infection not receiving hormone replacement therapy were included in this cross-sectional observational study. Based on Gram-stained smears, 30 women with a normal vaginal flora (Nugent score 0) were included in Group 1, and 30 women with an intermediate vaginal flora characterized by an absence of vaginal lactobacilli (Nugent score 4) were included in Group 2. Vaginal and rectal smears were taken for molecular lactobacillus profiling using polymerase chain reaction and denaturing gradient gel electrophoresis. Diversity of vaginal and rectal lactobacilli in postmenopausal women was the main outcome measure.

We noticed a minor interference of gut lactic acid bacteria on a normal vaginal microflora dominated by lactobacilli strains of the L. delbrueckii group. When the normal vaginal microflora is disturbed by depletion of lactobacilli, the gut may function as a reservoir for lactobacilli of the L. casei group, which then colonize the vagina.

Our data indicate that rectal lactobacilli may affect the vaginal flora of postmenopausal women in the case of lactobacillary absence and help to maintain a normal vaginal microbiota.