How should bacterial vaginosis (Gardnerella‑type vaginosis) be treated?

Treatment of Bacterial Vaginosis (Coccobacilli with Shift in Vaginal Flora)

Treat symptomatic bacterial vaginosis with metronidazole 500 mg orally twice daily for 7 days, which achieves a 95% cure rate and is the CDC's first-line recommended regimen. 1

When to Treat

• Only symptomatic women require treatment, as the principal goal is to relieve vaginal symptoms and signs. 2, 1
• Asymptomatic women should be treated before surgical abortion procedures, hysterectomy, or other invasive gynecological procedures to reduce post-procedural infections. 1, 3
• High-risk pregnant women with a history of preterm delivery should be treated even if asymptomatic, as BV is associated with preterm birth, premature rupture of membranes, and postpartum endometritis. 1

First-Line Treatment Options

Oral therapy:

• Metronidazole 500 mg orally twice daily for 7 days (preferred regimen with 95% cure rate) 2, 1
• Patients must avoid alcohol during treatment and for 24 hours afterward due to potential disulfiram-like reaction. 2, 1, 3

Intravaginal therapy (equally effective alternatives):

• Metronidazole gel 0.75% intravaginally once daily for 5 days 2, 1
• Clindamycin cream 2% intravaginally at bedtime for 7 days 2, 1
• Important caveat: Clindamycin cream is oil-based and may weaken latex condoms and diaphragms for up to 5 days after use. 1, 3

Alternative Regimens (Lower Efficacy)

• Metronidazole 2g orally as a single dose (84% cure rate, less effective than 7-day regimen) 2, 1
• Clindamycin 300 mg orally twice daily for 7 days 2
• Tinidazole 2g once daily for 2 days or 1g once daily for 5 days 1

Adjunctive Therapy to Reduce Recurrence

• Consider adding Lactobacillus probiotics as complementary therapy with antibiotics, which significantly improves cure rates (RR 1.53,95% CI 1.19-1.97). 1, 4
• The combination of metronidazole with probiotics shows particularly strong results for microbiological cure (OR 0.09,95% CI 0.03 to 0.26). 4

Critical Management Pitfalls to Avoid

• Do not treat male sex partners – this has not been shown to prevent recurrence or alter the clinical course in women. 2, 1, 3, 4
• Do not use culture for Gardnerella vaginalis as a diagnostic tool – it can be isolated from half of normal women and is not specific. 2
• Do not use tetracyclines – they are never recommended for BV treatment and resistance genes are clinically irrelevant. 3
• Counsel patients about high recurrence rates – 50-80% of women experience recurrence within 12 months, which may necessitate repeated treatments. 1, 3

Diagnostic Confirmation (Amsel Criteria)

Diagnosis requires at least 3 of the following 4 findings: 2, 1, 3, 4

• Homogeneous white discharge coating vaginal walls
• Clue cells on microscopic examination
• Vaginal pH >4.5
• Positive whiff test (fishy odor with 10% KOH)

Why Treatment Matters Beyond Symptoms

• BV increases risk for pelvic inflammatory disease, endometritis, and vaginal cuff cellulitis after invasive procedures. 2, 3, 4
• BV increases susceptibility to sexually transmitted infections including HIV. 3
• In pregnancy, untreated BV is associated with preterm delivery, low birth weight, and postpartum endometritis. 1