Bacterial vaginosis


☰ Contents :

Ⅰ. What is bacterial vaginosis ?

Ⅱ. Normal vaginal flora

The normal vaginal flora, Döderlein flora, is a constantly evolving environment, present from the first days of a little girl's life, it remains poor until puberty, then estrogen will induce the secretion of glycogen, the favorite substrate of Lactobacilli. spp. (Protective bacteria), the acidifying power of the latter is at the origin of a vaginal pH between 3.8 and 4.5 and thus makes it possible to rule out any multiplication of most pathogens.

lactobacillus function

Fig 1 : Function of lactobacilli in inhibiting pathogenic microorganisms(C. Ding, et al)



Ⅱ. Risk factors

Women with BV are at increased risk of contracting STIs, such as HIV, N. gonorrhoeae, C. trachomatis, T. vaginalis, M. genitalium, HPV, and HSV-2; complications after gynecological surgery; complications of pregnancy; and recurrence of BV


Note : Bacterial vaginosis is not a sexually transmitted infection (STI), but it can increase your risk of getting an STI such as chlamydia.


Ⅲ. Symptoms of bacterial vaginosis

◈ Anaerobes produce large amounts of carboxylase-like proteolytic enzymes, which break down vaginal peptides into a variety of volatile, smelly amines associated with increased vaginal transudation and exfoliation of squamous epithelial cells, resulting in the typical clinical features seen. in patients with BV


Ⅳ. Diagnosis of bacterial vaginosis

For a long time, Amsel's diagnostic criteria were the most commonly used clinical criteria. However, these criteria failed to diagnose asymptomatic BV. Subsequently, the Nugent score , developed in 1991, is currently considered the gold standard for the diagnosis of bacterial vaginosis.

Amsel's diagnostic criteria, it requires at least three of the following four symptoms or signs

  • Fine flow, white, yellow, homogeneous
  • Clue cells on microscopic examination
  • Vaginal fluid with a PH greater than 4.5
  • Odor of "rotten fish", either spontaneous or after adding a drop of 10% potash to vaginal secretions (sniff test)
Clue cells Gram stain

Clue cells

❷ Gram stain of vaginal flora, considered the gold standard laboratory method for the diagnosis of BV, is used to determine the Nugent score. A score of 0 to 3 is consistent with a vaginal microbiota predominantly of Lactobacillus, 4 to 6 with an intermediate microbiota (emergence of G. vaginalis) and 7 to 10 with bacterial vaginosis

The sensitivity and specificity of the Amsel criteria are respectively 37% to 70% and 94% to 99% compared to the Nugent score


Ⅳ. Bacterial vaginosis during pregnancy

WHO : There is some evidence that bacterial vaginosis is associated with an increased incidence of adverse pregnancy outcomes (eg, premature rupture of membranes, premature delivery, and low birth weight). Symptomatic pregnant women should be treated and those with a history of preterm labor should be screened for asymptomatic infections.

Pregnant women with recurrence of symptoms should be retreated. Screening of asymptomatic pregnant women without a history of preterm delivery is not recommended.


Ⅴ. Treatment (the American College of Obstetricians and Gynecologists)

Treatment is indicated for the relief of symptoms in women with symptomatic infection and for the prevention of postoperative infection in those with asymptomatic infection prior to abortion or hysterectomy. Note that BV resolves spontaneously in up to a third of non-pregnant women and half of pregnant women.

  • Metronidazole 500 mg orally twice / day for 7 days or
  • Metronidazole 0.75% gel one full applicator (5 g) intravaginally, once daily for 5 days or
  • Clindamycin 2% cream one full applicator (5 g) intravaginally at bedtime for 7 days

Recommended alternative treatments

  • Secnidazole (oral) 2 g as a single dose; or
  • Tinidazole (oral) 2 g once daily for 2 days, or 1 g once daily for 5 days; or
  • Clindamycin (oral) 300 mg twice daily for 7 days or 100 mg ova intravaginally once at bedtime for 3 days.

◈ Women should be advised to abstain from all sexual activity or to use condoms consistently and correctly during the treatment regimen. Douching may increase your risk of relapse.


References:

  1. The American College of Obstetricians and Gynecologists (ACOG) : Updated guidance 2020
  2. Caitlin Colonna : Amsel Criteria
  3. Linda et al : Exploring the global vaginal microbiome and its impact on human health
  4. CHANTAL BERTHOLOM: Comment interpréter un prélèvement vaginal chez la femme enceinte ?
  5. Jacques RAVEL : Bacterial Vaginosis and Its Association with Infertility, Endometritis, and Pelvic Inflammatory Disease
  6. CDC : Sexually Transmitted Infections Treatment Guidelines, 2021
  7. BONDARENKO Olga : Pratique du prélèvement vaginal par les médecins généralistes dans la prise en charge des vaginoses bactériennes
  8. OMS: GUIDELINES FOR THE MANAGEMENT OF SEXUALLY TRANSMITTED INFECTIONS
  9. Chuanfeng Ding: Bacterial Vaginosis: Effects on reproduction and its therapeutics
  10. Karen Powell - Bacterial vaginosis: diagnosis and treatment
  11. Jack D Sobel - Bacterial vaginosis: Clinical manifestations and diagnosis
  12. Jack D Sobel - Mixed vaginitis-more than coinfection and with therapeutic implications