Throughout the world, Bacterial Vaginosis (BV) is the most prevalent form of vaginal infection in women of reproductive age. This dysbiosis increases risks of reproductive complications, preterm delivery and susceptibility to sexually transmitted infections. Within a genital tract, BV is characterized by: (i) the depletion of resident commensal lactic-acid bacteria (mostly Lactobacillus spp.); (ii) an increase in bacterial diversity; and (iii) the overgrowth of pathogenic anaerobic bacteria probably owing to growth of Gardnerella vaginalis and establishment of a structured biofilm. Unfortunately, the etiology of BV is still unclear. Moreover, BV is a synergistic polymicrobial disease for which antibiotic therapies currently fail in the long-term (50% of recurrence). Phage therapy may thus be an alternative for treatment.

The aim of our project is to determine and further test experimentally how bacteriophages (both lytic and temperate) are involved in the etiology of BV. To achieve our objective, we first tested for the presence of temperate bacteriophages isolated and expressed (with mitomycin C) from Lactobacillus spp. sampled from healthy and dysbiotic genital tracts. Out of 32 isolated lactobacilli, eleven expressed prophages had head-tail structures characteristic to Siphoviridae, and 17 had isometric capsids either without tails or with very short tails. To determine the identity and polymorphism of phages, we plan to sequence their complete genomes using the Illumina HiSeq2500 platform with multiplexing. We further plan to test their infectivity and host-range.