Bacterial vaginosis (BV) is a vaginal infection caused by the decrease or absence of lactobacilli that normally produce hydrogen peroxide in the vagina and the increase of facultative anaerobes and anaerobes.


Causes

Common pathogens include facultative anaerobes such as gardnerella vaginalis; anaerobes such as prevotella, mobiluncus, bacteroides, and atopobium vaginae; ureaplasma urealyticum; and mycoplasma hominis.


Signs and Symptoms

There are not typical clinical manifestations. 10% - 40% of patients have no clinical symptoms. The main manifestations are increased, odorous vaginal discharges, aggravated after sexual intercourses, and mild genital pruritus or burning sensation. There are grayish white, homogeneous, thin discharges that often adhere to the vaginal wall, and the discharges can be easily wiped away from the vaginal wall. There is no inflammation of the vaginal mucosa.

The initial cure rate of bacterial vaginosis is 70% - 90%. The recurrence rate of bacterial vaginosis is 20% 1 month after treatment, 40% 3 months after treatment, and 60% 12 months after treatment.


Diagnosis

The diagnostic considerations include:

  • Positive clue cell test (the count of clue cells > 20% of the total vaginal epithelial cells)
  • Positive amine test
  • pH value of vaginal discharges > 4.5
  • Homogeneous, thin, and greyish white vaginal discharges

If the first consideration and at least 2 other considerations are present, the disease can be diagnosed.


Treatment

Systemic treatment

The recommended treatment regimen is metronidazole 400mg orally twice a day for 7 days. The alternative is tinidazole 2g orally once daily for 5 days, tinidazole 1g orally once daily for 5 days, or clindamycin 300mg orally twice daily for 5 days.

Topical treatment

The recommended treatment regimen is 0.75% metronidazole gel 5g vaginally once daily for 5 days, metronidazole suppository 200mg vaginally once daily for 5 - 7 days, 2% clindamycin ointment 5g vaginally once daily for 7 days, or clindamycin suppository 100mg vaginally once daily for 3 days.

Treatment for pregnant and lactating patients

The recommended regimen for pregnant patients is metronidazole 400mg orally twice a day for 7 days, or clindamycin 300mg orally twice a day for 7 days.

The lactating patients can be treated with only topical treatment, and the regimen is the same as those of other patients.