Research reveals underlying causes of recurrent bacterial vaginosis

Researchers in Australia have identified two contributors to recurrent bacterial vaginosis (BV) infections, a common sexual health condition that affects about a quarter of women around the world.

Recurrent BV may result from the condition persisting after antibiotics or from reinfection by a sexual partner, researchers found.

BV, occurs when the balance of naturally occurring vaginal bacteria changes, with fewer healthy bacteria and an overgrowth of other bacteria.

The study involved 188 heterosexual couples receiving concurrent treatment. Women took oral antibiotics for one week, while men received oral and topical antimicrobials.

Researchers from Monash University and Bayside Health’s Melbourne Sexual Health Centre investigated why around 20 per cent of women treated at the same time as their partners were not cured.

They identified two distinct pathways to recurrent BV: persistence despite the week-long antibiotic course and reinfection.

About two-thirds of women had returned to an optimal vaginal microbiome, characterised by an abundance of healthy Lactobacilli bacteria, the day after finishing treatment.

The remaining third had microbiomes suggesting they may not have cleared BV before couples resumed sex. These women were nearly three times more likely to develop BV again within four weeks.

Study lead author Dr Lenka Vodstrcil, senior research fellow at Monash University and Bayside Health’s Melbourne Sexual Health Centre, said understanding persistent infection could help improve treatment.

“A better understanding of persistence of infection … helps us develop new strategies to cure more women from BV,” Vodstrcil said.

The researchers described persistence and reinfection from partners as distinct but not mutually exclusive pathways to recurrent BV.

Around 30 per cent of women in the study used an intrauterine device. Researchers found this “could enhance the persistence of bacterial vaginosis following treatment in some women”, although further research was needed.

BV can cause vaginal itching, burning and discomfort, although some people have no symptoms. The condition can increase susceptibility to other infections and is linked to complications during pregnancy and childbirth.

The researchers now plan to trial longer treatment periods and combinations of multiple antibiotics.

“Our aim is to stop women from having two, three, four courses of antibiotics throughout the year, which was happening previously,” Vodstrcil said.

Professor Catriona Bradshaw, head of research translation and mentorship at Monash University and the Melbourne Sexual Health Centre, said: “Using partner-treatment to mitigate re-infection and more intensive strategies that target persistence of BV-bacteria, we hope to create more effective treatment approaches that can be tailored to an individual and achieve higher levels of cure.”

The researchers said participants’ ethnicities were representative of urban Australia, but cautioned that the findings might not be generalisable to other populations, including those in low-income and middle-income countries and settings with a high burden of BV.