It has long been debated whether bacterial vaginosis is sexually transmitted, with recent research proving that yes, BV can be sexually transmitted, but not always.
BV also occurs in women who are sexually inexperienced (read: never had any sex, of any kind, with anyone). It is a particular type of overgrowth of bacteria already present in the vagina, but it is not limited to just the vagina: it can grow on or in penises that have been inside affected vaginas, and be spread back and forth.
According to Verstraelen and Swidsinski (2013) cohesive Gardnerella vaginalis (a cluster of sticky cells that seed the biofilm are the ‘infective’ agent, and can be passed between sexual partners, men and women alike, having been found in urine and semen samples of men.
It was unclear, however, where the seed bacteria had come from in the semen samples, but was thought to be an external source such as the foreskin. This means that any male–female sexual partners also need to be treated to prevent the possible re-transmission of cohesive Gardnerella.
The study, Gardnerella biofilm involves females and males and is transmitted sexually, was published in the Gynaecology and Obstetrics Investigation in 2010 and had the following findings:
Over 350 people’s urine was tested, including pregnant women and their partners, who were randomly selected hospitalised patients (men, women and children). Gardnerella was found in two forms, cohesive and dispersed, with the cohesive form attaching to the epithelial cells in groups of highly concentrated bacteria. The dispersed form of Gardnerella were mixed with other bacterial groups.
Cohesive Gardnerella was found in all patients with proven BV and their partners: 7 per cent of men and 13 per cent of women; 16 per cent of pregnant women and 12 per cent of their male partners; and in no healthy lab staff or children.
There was a clear transmission link between sexual partners. Dispersed Gardnerella was found in 10-18 per cent of randomly selected females, 3-4 per cent of males, and 10 per cent of children (not sexually linked, can be passed from the mother).
Their conclusion was that cohesive Gardnerella biofilm is a distinct, clearly definable entity that involves both genders and is sexually transmitted. The authors have suggested that it be called gardnerellosis.