Characterization of culturable vaginal Lactobacillus species among women with and without bacterial vaginosis from the United States and India: a cross-sectional study.

Lactobacillus species play an integral part in the health of the vaginal microbiota. We compared vaginal Lactobacillus species in women from India and the USA with and without bacterial vaginosis (BV). Between July 2009 and November 2010, a cross-sectional study was conducted among 40 women attending a women's health clinic in Mysore, India, and a sexually transmitted diseases clinic in San Francisco, USA. Women were diagnosed with BV using Amsel's criteria and the Nugent score. Lactobacillus 16S rDNA was sequenced to speciate the cultured isolates. Ten Indian and 10 US women without BV were compared with an equal number of women with BV. Lactobacilli were isolated from all healthy women, but from only 10% of Indian and 50% of US women with BV. 16S rDNA from 164 Lactobacillus colonies was sequenced from healthy women (126 colonies) and women with BV (38 colonies). Seven cultivable Lactobacillus species were isolated from 11 Indian women and nine species from 15 US women. The majority of Lactobacillus species among Indian women were L. crispatus (25.0%), L. jensenii (25.0%) and L. reuteri (16.7%). Among US women, L. crispatus (32.0%), L. jensenii (20.0%) and L. coleohominis (12.0%) predominated. L. jensenii and L. crispatus dominated the vaginal flora of healthy Indian and US women. Indian women appeared to have a higher percentage of obligate heterofermentative species, suggesting the need for a larger degree of metabolic flexibility and a more challenging vaginal environment.