From the Guidelines
The recommended first-line treatment for Gardnerella vaginalis, a common cause of bacterial vaginosis (BV), is 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, as stated in the Centers for Disease Control and Prevention guidelines 1.
Treatment Options
- Metronidazole 500 mg orally twice daily for 7 days
- Metronidazole gel 0.75% intravaginally once daily for 5 days
- Clindamycin cream 2% intravaginally at bedtime for 7 days
Important Considerations
- Avoid alcohol consumption with metronidazole or tinidazole due to potential disulfiram-like reactions 1
- Sexual partners generally don't need treatment, but using condoms during treatment is recommended
- Bacterial vaginosis occurs when the normal vaginal flora balance is disrupted, allowing overgrowth of anaerobic bacteria including Gardnerella
- Symptoms typically include thin grayish-white discharge with a fishy odor, particularly noticeable after intercourse, though some women may be asymptomatic
Follow-up Evaluation
If symptoms persist after treatment, a follow-up evaluation is recommended as recurrence is common, affecting about 30% of women within 3 months of treatment 1.
Diagnosis
Bacterial vaginosis can be diagnosed by using the Amsel clinical criteria or Gram stain, as recommended by the U.S. Preventive Services Task Force 1. The Amsel criteria include:
- Vaginal pH greater than 4.7
- The presence of clue cells on wet mount
- Thin homogeneous discharge
- Amine “fishy odor” when potassium hydroxide is added to the discharge It is essential to note that the optimal treatment regimen for pregnant women with bacterial vaginosis is unclear, and treatment should be based on the clinical situation 1.
From the FDA Drug Label
Tinidazole is indicated for the treatment of bacterial vaginosis (formerly referred to as Haemophilus vaginitis, Gardnerella vaginitis, nonspecific vaginitis, or anaerobic vaginosis) in adult women [see Use in Specific Populations ( 8.1) and Clinical Studies ( 14.5)]. A randomized, double-blind, placebo-controlled clinical trial in 235 non-pregnant women was conducted to evaluate the efficacy of tinidazole for the treatment of bacterial vaginosis. A microbiologic diagnosis of bacterial vaginosis was based on Gram stain of the vaginal smear demonstrating (a) markedly reduced or absent Lactobacillus morphology, (b) predominance of Gardnerella morphotype, and (c) absent or few white blood cells, with quantification of these bacterial morphotypes to determine the Nugent score, where a score ≥4 was required for study inclusion and a score of 0 to 3 considered a microbiologic cure.
Treatment of Bacterial Vaginosis with Gardnerella
- Tinidazole is effective in treating bacterial vaginosis, including cases with Gardnerella morphotype.
- The recommended treatment regimens are 2 g once daily for 2 days or 1 g once daily for 5 days.
- Therapeutic cure rates for tinidazole were 97.5% and 93.2% for the 2-day and 5-day regimens, respectively, in a clinical trial 2.
- Tinidazole has in vitro activity against Gardnerella vaginalis, one of the bacteria associated with bacterial vaginosis 2.
From the Research
Vaginitis Swab Positive for Gardnerella
- A vaginitis swab positive for Gardnerella indicates the presence of Gardnerella vaginalis, a bacterium that can cause bacterial vaginosis (BV) 3, 4, 5.
- BV is a common infectious form of vaginitis, characterized by a milky discharge, pH greater than 4.5, positive whiff test, and clue cells in a wet-mount preparation 3.
- The standard treatment for BV is oral metronidazole, 500 mg twice daily for seven days 3, 6, 7.
- However, alternative treatments such as tinidazole, clindamycin, and secnidazole may be effective in treating BV, especially in cases of recurrence or metronidazole resistance 4, 6, 7, 5.
- Recurrence of BV is a common problem, with up to 50% of women experiencing recurrence within one year of treatment, and may be due to persistence of residual infection, resistance, or reinfection 7.
Treatment Options
- Oral metronidazole: 500 mg twice daily for 7-14 days 3, 6, 7.
- Tinidazole: 1 g daily for 5 days or a single 2 g oral dose 4, 5.
- Clindamycin: 300 mg twice daily for 7 days 6.
- Secnidazole: a single oral dose, may be an attractive new option for treating recurrent BV 7.
Considerations
- Adverse effects of metronidazole, such as gastrointestinal upset and metallic taste, may lead to poor adherence to treatment and treatment failure 4.
- Tinidazole has a more favorable side effect profile than metronidazole, with better gastrointestinal tolerability and less metallic taste 4.
- Recurrence of BV may require extended or alternative treatment regimens, such as metronidazole vaginal gel or secnidazole 7.