BV is a clinical syndrome caused by multiple microorganisms without inflammatory manifestations of the vaginal mucosa. BV also increases the risk of HIV infection in male partners. Although BV-associated bacteria can be found in the male genitalia, treating the male partner does not help prevent BV recurrence. 1. Diagnosis BV is diagnosed by the presence of at least three of the following four clinical features: (1) positive clue cells; (2) positive ammonia test; (3) vaginal pH greater than 4.5; and (4) homogeneous thin vaginal discharge. Application of Gram stain microscopy of vaginal smear or enzyme rapid test such as BV blue can be used to diagnose BV. DNA probes such as VP III microbial confirmation test can be used to diagnose BV. PCR method is used to study a range of microorganisms associated with BV and is not used for clinical diagnosis. Microbial culture is not used as a diagnostic method. The cervical Pap test has no clinical value for BV diagnosis because of its low sensitivity. All patients with BV need to be tested for HIV and other STDs. 2. Treatment Implications of non-pregnancy treatment: (1) Reduction of signs and symptoms of vaginal infection; (2) Reduction of risk of complications from abortion or hysterectomy infection. Other potential benefits include reduction in the risk of other infections such as HIV infection and other STDs. Treatment is required for all patients with symptomatic BV. Recommended regimen: metronidazole 500 mg orally, 2 times/d for 7 d; or 0.75% metronidazole cream (5 g), vaginally, 1 time/d for 5 d; or 2% clotrimazole cream (5 g), vaginally, once nightly for 7 d. Alternative regimen: tinidazole 2 g orally, 1 time/d for 2 d. tinidazole 1 g orally, 1 time/d for 5 d. clotrimazole 300 mg. During treatment, patients are advised to avoid sexual contact or use condoms properly. Vaginal douching may increase the risk of recurrence of BV, and there is no evidence that douching can treat or relieve symptoms. There are no studies to support the use of lactobacillus preparations or probiotics as an alternative or adjunctive treatment for BV. Follow-up: Routine follow-up is not required after resolution of symptoms; recurrence of BV is common and patients are advised to follow up when symptoms recur. Certain BV-associated microorganisms and drug resistance are associated with subsequent treatment failure, and research on the optimal treatment strategy for persistent or recurrent BV is limited. Different treatment regimens are available for relapsing patients, with initial relapses remaining on the same treatment regimen as the previous one. For patients with multiple relapses after treatment with the recommended regimen, suppressive treatment with metronidazole gel, i.e., metronidazole gel twice weekly for 4 to 6 months, may be used to reduce relapses, but efficacy may be discontinued with interruption of suppressive treatment. After oral nitroimidazole therapy, intravaginal boric acid and metronidazole gel suppressive therapy applied during remission may be used to treat recurrent BV. monthly oral metronidazole plus fluconazole may also reduce BV recurrence and promote normal vaginal flora formation. Management of sexual partners: Routine treatment of sexual partners is not advocated. 3. Special considerations Allergy or intolerance to recommended drugs: Application of clotrimazole cream is an option for those who are allergic or intolerant to metronidazole and tinidazole. Those who are intolerant to oral metronidazole may choose to apply topical metronidazole treatment. Alcohol is prohibited within 24h of taking metronidazole and within 72h of taking tinidazole. Pregnancy: BV is associated with adverse pregnancy outcomes including premature rupture of membranes, preterm delivery, amniotic cavity infection, and postpartum endometritis, but the only established benefit of treatment of BV during pregnancy is relief of signs and symptoms of vaginal infection. Oral medications for symptomatic BV are not superior to topical medications in terms of efficacy and prevention of adverse pregnancy outcomes, and treatment of symptomatic pregnant women is the same as in nonpregnancy. Clindamycin is safe for use in pregnant women. Metronidazole can cross the placenta, but no increased risk of fetal malformations or organismal cell mutations has been found with metronidazole application during pregnancy. Tinidazole is a pregnancy category C drug and is not indicated for use in pregnant women. There is still no consensus to assess the feasibility of screening for BV in pregnant women at high risk of preterm delivery. Metronidazole is secreted through breast milk and delayed breastfeeding for 12-24 h is recommended for those taking 2 g of oral metronidazole, less than this dose can be breastfed. Treat all symptomatic pregnant women. The cure rate for both oral metronidazole and topical application of metronidazole cream was 70% (Amsel criteria). The cure rate for oral clindamycin is 85% (Gram stain method). HIV infection: HIV patients have a high incidence of BV. BV treatment for HIV patients is the same as for non-HIV patients.