What is the recommended treatment for a male partner of a female patient with recurrent bacterial vaginosis?

Treatment of Male Partners in Bacterial Vaginosis

Routine treatment of male partners is NOT recommended for bacterial vaginosis based on current CDC guidelines, though groundbreaking 2025 evidence suggests this recommendation may need revision. 1

Current Guideline-Based Recommendation

The CDC explicitly states that treatment of male sex partners has not been shown to alter either the clinical course of BV in women during treatment or the relapse/recurrence rate, and therefore routine treatment of sex partners is not recommended. 1

Key Points from Guidelines:

• Male partners of women with BV are typically asymptomatic and do not require treatment 1
• Clinical trials through 2002 consistently showed that partner treatment did not influence the woman's response to therapy or recurrence rates 1
• The principal goal of BV therapy is to relieve vaginal symptoms in the affected woman, not to prevent transmission to men 1
• BV is not considered exclusively a sexually transmitted disease, though it is associated with sexual activity 1

Critical New Evidence That Challenges Guidelines

A 2025 randomized controlled trial published in the New England Journal of Medicine demonstrated that treating male partners with combination oral metronidazole (400 mg twice daily) plus topical 2% clindamycin cream (applied to penile skin twice daily) for 7 days significantly reduced BV recurrence in women from 63% to 35% over 12 weeks (P<0.001). 2

Details of the 2025 Trial:

• The trial was stopped early by the data safety monitoring board because treatment of women only was clearly inferior to treating both partners 2
• Absolute risk reduction was 2.6 recurrences per person-year (95% CI: -4.0 to -1.2) 2
• This represents a 44% relative reduction in recurrence risk 2
• The combination therapy (oral + topical) was well-tolerated by men, with only mild adverse events including nausea, headache, and metallic taste 2

Supporting Microbiological Evidence:

• A 2021 pilot study showed that concurrent partner treatment significantly reduced BV-associated bacteria at all three anatomical sites (vagina, penile skin, and male urethra) immediately post-treatment 3
• Suppression of BV-associated bacteria was sustained in 81% of women over 12 weeks in this cohort 3
• 16S rRNA gene sequencing confirmed that BV-associated bacteria colonize male genital sites and can be reduced with treatment 3

Critical Analysis of Previous Negative Trials

A 2012 systematic review revealed that all six prior randomized trials showing no benefit of partner treatment had significant methodological flaws that likely explain their negative results. 4

Major Flaws in Historical Trials:

• Randomization methods were either overtly deficient or insufficiently reported 4
• Five of six trials used suboptimal treatment regimens in women 4
• Adherence to treatment was not reported in women in any trial, and only reported in men in 2 trials 4
• All six trials had limited statistical power to detect clinically meaningful differences 4
• None assessed whether antibiotic treatment actually affected the penile microbiota 4

Clinical Approach for Recurrent BV

For Initial BV Episode:

Do NOT routinely treat male partners, as this remains the current CDC guideline recommendation. 1

For Recurrent BV (≥2 episodes within 12 months):

Consider discussing partner treatment as an option, particularly for women in monogamous heterosexual relationships, given the compelling 2025 evidence. 2

Partner Treatment Regimen (if pursued):

• Male partner: Metronidazole 400 mg orally twice daily PLUS 2% clindamycin cream applied to penile skin twice daily, both for 7 days 2
• Female partner: Standard first-line BV treatment (metronidazole 500 mg orally twice daily for 7 days OR metronidazole gel 0.75% intravaginally once daily for 5 days OR clindamycin cream 2% intravaginally at bedtime for 7 days) 1

Important Counseling Points:

• Both partners must avoid alcohol during metronidazole treatment and for 24 hours afterward to prevent disulfiram-like reactions 1
• Clindamycin cream is oil-based and may weaken latex condoms and diaphragms for several days after use 1
• Current CDC guidelines have not yet been updated to reflect the 2025 evidence 5, 6
• More research is needed to determine if these results apply to broader populations beyond the Australian cohort studied 6

Common Pitfalls to Avoid

• Do not use oral metronidazole alone for male partners - the 2025 trial specifically used combination oral + topical therapy, and previous trials using oral therapy alone failed 2
• Do not assume all recurrences are due to reinfection from partners - biofilm formation and persistence of residual infection also contribute to recurrence 7
• Do not treat partners without ensuring adequate treatment of the female patient first - suboptimal treatment in women was a major flaw in previous negative trials 4
• Do not forget to counsel about alcohol avoidance - this is critical for preventing disulfiram-like reactions with metronidazole 1

Alternative Approach for Recurrent BV Without Partner Treatment

If partner treatment is not pursued, extended metronidazole therapy remains the guideline-recommended approach for recurrent BV: 7

• Metronidazole 500 mg orally twice daily for 10-14 days 7
• If ineffective, metronidazole gel 0.75% intravaginally for 10 days, followed by twice weekly for 3-6 months 7
• No long-term maintenance regimen beyond 3-6 months is currently recommended 8