What is the treatment for Gardnerella vaginosis (bacterial vaginosis)?

Treatment of Bacterial Vaginosis (Gardnerella vaginosis)

For bacterial vaginosis, the first-line treatment is metronidazole 500 mg orally twice daily for 7 days, which is highly effective and recommended by CDC guidelines. 1

First-Line Treatment Options

The CDC recommends several equally effective first-line treatment options:

• Oral options:

  • Metronidazole 500 mg orally twice daily for 7 days 1

• Topical options:

  • Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days 1, 2
  • Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days 1

Alternative Treatment Regimens

• Tinidazole 2g orally once daily for 2 days 3
• Tinidazole 1g orally once daily for 5 days 3
• Clindamycin 300 mg orally twice daily for 7 days 1
• Clindamycin ovules 100g intravaginally once at bedtime for 3 days 1

Special Considerations for Pregnant Women

• First trimester: Clindamycin vaginal cream is preferred due to metronidazole contraindication 1
• After first trimester: Metronidazole 500 mg orally twice daily for 7 days 1
• Alternative for pregnant women: Metronidazole 250 mg orally three times daily for 7 days 1, 4

Diagnosis Criteria

Bacterial vaginosis diagnosis requires confirming at least 3 of 4 Amsel's criteria:

1. Homogeneous, white, non-inflammatory discharge adhering to vaginal walls
2. Presence of clue cells on microscopic examination
3. Vaginal fluid pH greater than 4.5
4. Fishy odor of vaginal discharge before or after addition of 10% KOH (whiff test) 1

Gram stain results consistent with BV include:

• Markedly reduced or absent Lactobacillus morphology
• Predominance of Gardnerella morphotype
• Absent or few white blood cells 2

Important Precautions

• Patients should avoid alcohol during metronidazole treatment and for 24 hours afterward to prevent disulfiram-like reactions 1
• Clindamycin cream and ovules are oil-based and might weaken latex condoms and diaphragms 1
• Rule out other common pathogens associated with vulvovaginitis (Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, Candida albicans, and Herpes simplex virus) 3, 2

Management of Recurrent BV

Recurrence is common, with 50-80% of women experiencing recurrence within a year of treatment 1, 5. For recurrent BV:

• Extended course of metronidazole (500 mg twice daily for 10-14 days) 5
• If ineffective, metronidazole vaginal gel 0.75% for 10 days, followed by twice weekly for 3-6 months 5

Partner Treatment

• Routine treatment of sex partners is not recommended, as clinical trials indicate that partner treatment does not affect a woman's response to therapy or likelihood of relapse/recurrence 1
• However, recent research suggests women with untreated regular sexual partners may be more likely to experience recurrence than women with no partners or partners who received treatment 6

Follow-up

• Routine follow-up is unnecessary if symptoms resolve 1
• For high-risk pregnant women, follow-up evaluation 1 month after treatment completion is recommended to evaluate treatment effectiveness 1

Treatment Efficacy

Clinical studies show similar cure rates for oral metronidazole (84.2%), metronidazole vaginal gel (75.0%), and clindamycin vaginal cream (86.2%) using traditional clinical and laboratory criteria 7. Recent research suggests that higher abundance of Prevotella before treatment and persistence of Gardnerella immediately after treatment are associated with increased odds of BV recurrence 6.