Bacterial Vaginosis

See also

Vaginitis

Epidemiology

Accounts for 35-50% of Vaginitis

Risk Factors

Vaginal Douching
Tobacco Abuse
New or multiple sexual partners
Unprotected intercourse
Women Who Have Sex With Women

Etiology

Marked reduction in normally predominant lactobacillus
Polymicrobial infection: facultative Anaerobic Bacteria
1. Peptostreptococcus
2. Gardnerella Vaginalis (Corynebacterium vaginale, Haemophilus vaginalis)
3. Bacteroides
4. Mobiluncus species
5. Mycoplasma hominis
6. Ureaplasma
7. Prevotella

Symptoms

Often asymptomatic, or mild
Musty or fishy odor to genitalia or Vaginal Discharge
Profuse thin gray-white, non-clumping Vaginal Discharge

Signs
Amsel Criteria (3 of 4 needed for diagnosis)

Vaginal pH > 4.5 (more alkaline than normal)
1. See Vaginal pH for differential diagnosis
2. Test Sensitivity: 77%
3. Test Specificity: 35%
  1. False Positive with Cervical Mucus, Menses or semen
Clue Cells present (on >20% of cells) on saline preparation
1. Bacteria adhered to vaginal epithelial cells
2. Test Sensitivity: 53-90%
3. Test Specificity: 40-100%
4. Images
Positive whiff test (Amine Test)
1. Test Sensitivity: 67%
2. Test Specificity: 93%
3. Volatile amines produce a fishy odor with 10% KOH
4. Also present with Trichomonal Vaginitis
Discharge characteristics
1. Thin, non-clumping, gray-white, adherent discharge
Efficacy of Amsel Criteria: At least 3 of 4 findings present
1. Test Sensitivity: 70-97%
2. Test Specificity: 90-94%

Labs
Non-Microscopy

High sensitivity and Specificity tests (>92% Test Sensitivity and Specificity)
1. DNA Probe Test (e.g. Affirm VPIII Microbial Identification Test)
  1. Identifies candida, gardnerella vaginalis, Trichomonas
2. Sialidase Activity
  1. Specific for gardnerella vaginalis
Older tests
1. Fem Exam Card 1 (pH and amine) and 2 (Proline aminopeptidase)
  1. Rapid, 2 minute test with high sensitivity (91%) but low Specificity
2. Trimethylamine Card for pH
  1. Rapid test with Low sensitivity, but high Specificity (97%)

Management

Non-Pregnant
1. Test and treat only symptomatic patients
2. First-Line: Oral Metronidazole (Flagyl)
  1. Flagyl 500 mg orally twice daily for 7 days
3. Other oral options
  1. Clindamycin 300 mg orally twice daily for 7 days
  2. Tindazole (Tindamax) 2 g orally once daily for 2 days (or 1 g orally daily for 5 days)
  3. Secnidazole (Solosec) 2 grams for single dose
    1. Sprinkle entire packet into applesauce, yogurt or pudding
    2. Avoid in pregnancy and Lactation
    3. Risk of Vulvovaginal Candidiasis
    4. Expensive in 2018 ($270, instead of $10 for Metronidazole)
    5. (2018) presc lett 25(7): 42
4. Topical, intravaginal options (higher recurrence rate, does not cover Trichomoniasis)
  1. MetroGel (0.75%) 37.5 mg per 5g applicator intravaginally at bedtime for 5 days
  2. Clindamycin
    1. Clindamycin Cream (2%) 5g applicator intravaginally at bedtime for 7 days
    2. Clindamycin Ovules (Cleocin Ovules) 100 mg intravaginally at bedtime for 3 days
    3. Clindamycin Topicals weaken latex Condoms, diaphragms until 3 days after stopping
  3. Dequalinium Vaginal Tablets (not available in U.S.)
    1. Taken 10 mg tablet intravaginally for 7 days
    2. Noninferior to Metronidazole orally
      1. Raba (2024) JAMA Netw Open 7(5): e248661 [PubMed]
Pregnancy
1. Precautions
  1. Bacterial Vaginosis is associated with Preterm Labor
  2. Treat all symptomatic Bacterial Vaginosis cases in pregnancy (but screening not indicated)
2. First Trimester
  1. Avoid treatment if possible in first trimester
  2. Clindamycin (Cleocin) 300 mg PO bid for 7 days
  3. Clindamycin Cream 5 grams PV qhs for 7 days
  4. Metronidazole Gel PV bid for 5 days
3. After First Trimester (prefer after 37 weeks)
  1. Metronidazole (Flagyl) 500 mg twice daily for 7 days
  2. Metronidazole (Flagyl) 250 mg three times daily for 7 days
  3. Clindamycin 300 mg orally twice daily for 7 days
Resistant or Refractory Cases
1. Metronidazole 500 mg orally twice daily for 14 days (preferred) or
2. Consider treating sexual partner and patient (not recommended)
  1. Male Urethra may be co-infected
  2. Based on anecdotal reports (evidence lacking)
3. Other options
  1. Clindamycin at above dose
  2. Povidone-Iodine gel OR suppository (Betadine)
    1. Apply vaginally bid for 14 to 28 days ($59)
Recurrent Bacterial Vaginosis (common)
1. Treat as refractory cases above
2. Combined protocol
  1. Metronidazole 500 mg twice daily for 7 days AND followed by
  2. Boric Acid gelatin cap 600 mg intravaginallyat bedtime for 21 days AND followed by
  3. Metronidazole vaginal gel one 5 g applicator twice weekly for 16 week
  4. Reichman (2009) Sex Transm Dis 36:732-4 PMID:19704395 [PubMed]
3. Consider maintenance therapy
  1. Induction: Metronidazole gel 0.75% (Metrogel) nightly for 10 days
  2. Maintenance: When Wet Prep with no clue cells, pH lower
    1. Metronidazole gel twice weekly or (2 g oral monthly) for 3-6 months
    2. Treat concurrent Candida if present (e.g. Fluconazole 150 mg once monthly)
4. References
  1. Sobel (2006) Am J Obstet Gynecol 194(5): 1283-9 [PubMed]

Complications
Sexually Transmitted Infection

Associated with higher risk of HIV Transmission, as well as Gonorrhea, Chlamydia and Genital Herpes
1. Martin (1999) J Infect Dis 180(6):1863-8 [PubMed]

Complications
Pregnancy

Antibiotic treatment has not be found to reduce preterm birth risk
1. Brocklehurst (2013) Cochrane Database Syst Rev (1):CD000262 +PMID:23440777 [PubMed]
Originally thought to be associated with preterm delivery (23-26 weeks)
1. Hillier (1995) N Engl J Med 333: 1737-42 [PubMed]
2. Hauth (1995) N Engl J Med 333: 1732-6 [PubMed]
Originally, second trimester treatment with Clindamycin was found with better pregnancy outcomes
1. Reduced preterm birth and late Miscarriage rate
2. Ugwumadu (2003) Lancet 361:983-8 [PubMed]

References