Bacterial vaginosis (BV), affecting up to 30% of young women, has a high recurrence rate, with over 50% of women experiencing reinfection within 12 weeks. The cause of BV is poorly understood, but women who report sex with a regular partner have twice the risk of those who are not sexually active. This observation has led to speculation that the condition is sexually transmitted. However, previous studies where females and their male partners were treated with oral therapy have not demonstrated a reduction in recurrence. One possible explanation for these findings is that oral therapies alone may not be sufficient to clear cutaneous penile carriage of bacterial vaginosis–associated organisms. To test this theory, Australian researchers randomized monogamous couples in which the woman had BV to female-only treatment (female-only group) or female and male partner treatment (partner-treatment group). In both groups, females received metronidazole 400 mg twice daily for 7 days or intravaginal metronidazole or clindamycin if contraindicated. In the partner-treatment group, males received the same metronidazole regimen along with 2% clindamycin cream applied to the penile skin twice daily for 7 days. During follow-up, females were tested for BV at day 8, week 4, week 8, week 12, and as needed for symptoms. At study conclusion, the primary outcome, BV recurrence within 12 weeks, was significantly lower in the partner-treatment group compared to the female-only group (35% vs 63%, p<0.001)

This study provides some insight into BV and sexual transmission. It also raises the question of whether topical therapy alone in male partners, including over-the-counter creams like Neosporin, could reduce recurrence. Lastly, it's important to note that 35% of women in the partner-treatment group had a recurrence, suggesting that some type of underlying predisposition plays a significant role in BV susceptibility.

• Male-Partner Treatment to Prevent Recurrence of Bacterial Vaginosis, NEJM (2025)
• Genitourinary infections