Bacterial Vaginosis

Woman's Diagnostic Cyber Disease Profile

BV, anerobic vaginitis, nonspecific vaginitis, Gardnerella vaginitis, haemophilis vaginitis

General description

Inflammation of the vagina due to a bacterial infection which results in a thin, gray-white to yellow discharge and a "musty" or "fishy" odor.

Is it common?

It is the most common cause of vaginitis explaining up to 50% of vaginal infections. Differentiating
features homogeneous, thin gray-white discharge; pH of vaginal secretions is >4.5;
presence of clue cells (vaginal epithelial skin cells) covered with bacteria;
positive whiff test (mixing KOH with vaginal secretions produces fishy odor);
gram stain as a screening criteria may be more effective than the above clinical criteria in some situations (1, 2);

Other features

Can cause odor and some itching although not as much as with a yeast (candida) infection. Mild vulvar irritation is present in up to 20% of cases. Cause Change in bacterial flora with a loss of the normally occurring vaginal lactobacilli and an increase in other anaerobic bacteria such as bacteroides, peptostreptococcus, mobiluncus and mycoplasma. The vaginal anerobic (without oxygen) to aerobic (with oxygen) bacteria ratio is 1000 to 1, normal vaginal flora is 5 to 1 ratio.

Unnecessary studies

For the isolated or infrequent periodic episode of vaginal discharge, bacterial culture has predictive value of only 50% so it is not routinely used (3, 4), however in chronic, recurrent episodes, it may be useful to pick up less frequently occuring bacterial species such as group B or D strep or E.coli (5, 6). Routine screening does not seem to prevent normal sequelae and routine treatment of sex partner does not seem to prevent or lessen recurrence.

Natural history untreated

Vaginal discharge, odor and some itching or irritation will continue. Improvement may occur over several months. Infections tend to predispose women to pelvic inflammatory disease, post surgical (hysterectomy) infection, and in pregnancy, chorioamnionitis, premature rupture of membranes, preterm delivery, neonatal sepsis, postpartum endometritis,

Goals of therapy (Rx)

To restore normal vaginal bacteria by inhibiting anaerobic bacteria but not the normal vaginal lactobacilli, in order to eliminate symptoms of discharge and odor and to prevent later sequelae. 1st choice therapy metronidazole orally (Flagyl®) 500mg twice a day for 7 days (95% cure); OR clindamycin (Cleocin®) 300 mg orally twice a day for 7 days (94% cure); OR metronidazole vaginal cream 0.75% (Metrogel®) 1 applicator intravaginal each day for 5 days (75% cure); Other therapies used metronidazole, 2000 mg orally as a single dose (4, 500mg tablets) (84% cure); clindamycin 2% vaginal cream, 1 applicator (5gm) intravaginal each day for 7 days (86% cure); metronidazole vaginal cream 0.75% (Metrogel®) 1 applicator intravaginal each day for 3 days (75% cure); exogenous lactobacillus recolonization by vaginal tablets or suppositories containing lactobacillus or oral tablets with lactobacilli that recolonize the gastrointestinal tract.

Treatments to avoid

Antibiotics with activity against lactobacilli. Reason for Rx
choices Metronidazole has excellent activity against anaerobes but poor activity against lactobacilli. It's cure rate is excellent and it also covers trichomonas vaginitis with sometimes coexists with bacterial vaginosis. References

Beckmann, CRB et al. (eds.)Obstetrics and Gynecology. 3rd edition. Baltimore: Williams and Wilkins, 1998.
Sobel JD: Vaginitis. N Engl J Med 1997;337(26):1896-903.