Do you treat bacterial vaginosis (BV) caused by organisms such as Prevotella bivia found on a vaginal swab?

Treatment of Bacterial Vaginosis Organisms on Vaginal Swab

Organisms like Prevotella bivia found on vaginal swab should be treated only if they are part of a clinical diagnosis of bacterial vaginosis (BV) based on established diagnostic criteria, not based on culture results alone. 1

Diagnosis of Bacterial Vaginosis

BV is diagnosed when 3 of the 4 Amsel criteria are present:

1. Homogeneous, white, thin discharge that smoothly coats the vaginal walls
2. Vaginal pH > 4.5
3. Positive "whiff test" (fishy odor when 10% KOH is added to vaginal secretions)
4. Presence of clue cells on microscopic examination 2, 1

Alternatively, Gram stain of vaginal secretions can be used as the diagnostic standard 3.

Key Points About Organisms Mentioned

• Prevotella bivia: This is a normal component of the vaginal flora that can become overgrown in BV 4. Finding it on culture alone is not an indication for treatment.
• Enterococcus faecalis: Not typically associated with BV and not an indication for treatment when found on vaginal swab without symptoms.
• Lactobacillus spp: These are beneficial bacteria that protect the vagina. Their presence is normal and should NOT be treated 2, 1.

Treatment Algorithm

1. If asymptomatic with normal findings on exam:

   • No treatment needed regardless of organisms identified on culture 2, 1
   • Exception: Consider treatment in high-risk pregnant women to prevent preterm delivery 2

2. If symptomatic with 3 or more Amsel criteria (confirmed BV):

   • First-line treatment: Metronidazole 500 mg orally twice daily for 7 days (95% cure rate) 1
   • Alternative treatments:
     • Metronidazole gel 0.75% intravaginally once daily for 5 days
     • Clindamycin cream 2% intravaginally at bedtime for 7 days
     • Clindamycin 300 mg orally twice daily for 7 days 1, 5

3. For pregnant women:

   • First trimester: Clindamycin cream preferred
   • Second/third trimester: Either metronidazole or clindamycin 1

Special Considerations

• Recurrent BV: Occurs in 50-80% of women within the first year after treatment 1, 6

  • Extended treatment: Metronidazole 500 mg twice daily for 10-14 days
  • Maintenance: Metronidazole gel 0.75% twice weekly for 3-6 months 1, 6

• Important precautions:

  • Avoid alcohol during metronidazole treatment and for 24 hours afterward
  • Clindamycin creams can weaken latex condoms 1

Common Pitfalls to Avoid

1. Do not treat based on culture results alone - The presence of organisms like Prevotella bivia on culture without clinical signs of BV does not warrant treatment 2

2. Do not treat Lactobacillus - These are protective organisms whose presence indicates healthy vaginal flora 2, 1

3. Do not routinely treat sexual partners - Treatment of male partners has not been shown to prevent BV recurrence 2

4. Do not confuse BV with other vaginal infections - Vulvovaginal candidiasis presents with thick, white discharge and normal pH (≤4.5), while BV has thin, homogeneous discharge with pH >4.5 1, 3

BV is associated with increased risk of pelvic inflammatory disease, postoperative infections, and adverse pregnancy outcomes, making proper diagnosis and treatment important for reducing morbidity 2, 7.