Phages and Bacterial Vaginosis

Abstract

Bacterial vaginosis (BV) was previously called nonspecific vaginitis or Gardnerella-associated vaginitis. Symptomatic women report an offensive, fishy-smelling discharge, which is most marked after unprotected intercourse or at the time of menstruation. It is unknown how BPDE promotes the induction of prophages in lysogenic lactobacilli. The study of the Escherichia coli lambda phage, however, may shed some light on this question. The number of vaginal lactobacilli can be reduced in a smoking woman: by inducing the lysogenic strains to lyse and release phages or when the released phages may in turn lyse other strains by infection. The relationship between smoking and BV may be much more complicated, since smoking can weaken the human immune system and also cause many other health problems. The author and coworkers have documented that phages infect vaginal lactobacilli under in vitro conditions. This suggests that phage infection may occur in vivo as well. DNA evidence of phages were sought in different vaginal lactobacilli that would suggest an infection and/or transmission of phages in women and evidence that phages are released from the male urinary tract. The major difference is that lysogenic bacteria are capable of releasing phages, either spontaneously or upon induction, such as by cigarette chemicals. Collectively, this study provides initial evidence that vaginal Lactobacillus phages can be transmissible infective agents. In summary, some vaginal and yogurt lactobacilli are lysogens that spontaneously release phages. Future studies should include establishing phage taxonomy, characterizing phage diversity, determining phage genomic sequences, and studying interactions between phages and lactobacilli.