Investigation of bacteriophages and bacteriocins in vaginal lactobacilli

In this study, a total of 100 lactobacilli were isolated and identified by standard bacteriological methods and screened for the presence of bacteriophages (prophage) and production of bacteriocins from the vaginal samples of 75 reproductive women admitted to the Obstetrics and Gynecology Department of Farabi Hospital and Trabzon Delivery Hospital. Of 100 lactobacilli, nine different species were identified, among which L. gasseri was found to be the most common (%44) species. Using mitomycin C induction, 56% of all lactobacilli were found to carry prophages. These prophages were characterized and grouped into three different morphotypes: 14 of them belonged to group A, 37 to group Bl and 5 to group B2 bacteriophages. Prophages were mostly detected in 88% of lactobacilli isolated from the women with bacterial vaginosis. Regardless of the source of lactobacilli, L. delbrueckii subsp. delbrueckii "was found to carry prophages more frequently compared to the other species. Three bacteriophages namely the tl074c and Otl076 carried by three lactobacilli isolated from three women, who were inhabitants of three distinct regions, were found to be identical by morphology and genetic analysis. Six strains of lactobacilli were observed to have bacteriocin activity against Gardnerella vaginalis and Pseudomonas aeruginosa as well as other lactobacilli. As a result, in vitro bacteriophage infection of different lactobacilli isolated from different women suggested that prophage carrying lactobacilli in the vaginal flora of women may have the potential to eliminate the sensitive indigenous lactobacilli upon prophage induction. This in turn may lead to an increase in the vaginal pH and provide environment for the other pathogens to colonize the vagina and cause vaginal infections.