Bacterial Vaginosis (BV) is a common condition resulting from an imbalance in the vaginal flora. Beneficial Lactobacilli decrease while other bacteria, such as Gardnerella vaginalis and Prevotella species, overgrow. While men cannot technically develop BV because they lack the specific vaginal environment necessary for this bacterial shift, they play a recognized role as asymptomatic carriers of the associated bacteria. Testing protocols for men differ significantly from those for women, focusing primarily on their potential role in BV transmission and recurrence.
Understanding BV and Male Involvement
The defining characteristic of BV is the disruption of the vaginal microbiome, an environment unique to people with a vagina. Since men do not possess this environment, they cannot spontaneously develop Bacterial Vaginosis itself. However, male partners of women with BV can carry the associated bacteria, such as Gardnerella vaginalis and Sneathia species, on the skin of the penis or within the urethra.
Bacterial carriage by men is a significant factor in the high rate of BV recurrence observed in women. During sexual intercourse, the bacteria are exchanged between partners. The presence of these bacteria in the male partner can potentially reintroduce them into the female partner after she has completed antibiotic treatment. Studies show a high concordance of BV-associated bacteria between heterosexual partners. The presence of these organisms, particularly in the sub-preputial space of uncircumcised men, establishes a reservoir that contributes to the cycle of reinfection.
Symptoms and Health Implications for Men
For the majority of male carriers, the presence of BV-associated bacteria is asymptomatic and does not cause a noticeable infection. The bacteria often reside as part of the normal penile microbiota without causing physical signs or discomfort. In rare instances, the presence of these organisms has been linked to conditions like non-gonococcal urethritis, which is an inflammation of the urethra.
When men do experience symptoms, they are usually mild, including penile discharge, itching, or a burning sensation. These symptoms are more commonly caused by other infections, such as thrush or a different sexually transmitted infection (STI). A significant implication of carrying BV-associated bacteria is the increased risk of acquiring or transmitting other STIs, particularly HIV. This altered bacterial community may create an environment that makes the acquisition of other pathogens easier.
Diagnostic Procedures for Male Partners
Routine screening or testing for BV-associated bacteria is not recommended for asymptomatic male partners by major health organizations, such as the Centers for Disease Control and Prevention (CDC). This is because the clinical relevance of a positive test in a man without symptoms is not fully established, and the bacteria often clear on their own. Diagnosis focuses instead on the symptomatic female partner.
When testing is performed, usually in a research setting or if the man is symptomatic, specific laboratory methods detect the presence of BV-associated organisms. These methods include Nucleic Acid Amplification Tests (NAAT) or Polymerase Chain Reaction (PCR) testing, which are highly sensitive for detecting the DNA of specific bacteria like G. vaginalis in urethral swabs or urine samples. Culture methods or microscopic examination of a urethral swab may also be employed. However, there is no single, reliable diagnostic test for BV carriage in men. The limitations of these tests mean they primarily confirm the presence of bacteria rather than diagnosing a clinical disease.
Treatment Recommendations for Male Partners
Clinical guidelines for treating male partners are evolving, though the CDC’s 2021 guidelines still recommend against routine treatment. The approach shifts significantly if the female partner experiences recurrent BV, defined as three or more episodes per year. In these cases, evidence suggests that treating the male partner can significantly reduce the recurrence rate in the female partner.
A recent randomized controlled trial showed that treating both partners reduced recurrence in women from 63% to 35% within a 12-week period. This dual-partner treatment regimen typically involves a combination of oral and topical antibiotics for the male partner. The standard protocol includes oral metronidazole (400 mg taken twice daily for seven days) combined with a topical application of 2% clindamycin cream to the glans and penile shaft (also twice daily for seven days). Couples are advised to abstain from sexual contact during the one-week treatment period to ensure effectiveness and prevent re-exposure.