BV is a clinical syndrome that occurs when the normal H 2O2-producing Lactobacillus species in the vagina are replaced by high concentrations of anaerobic bacteria, G. vaginalis, and Mycoplasma hominis. BV is the most common cause of a malodorous discharge, but over half of the women who meet the clinical criteria for diagnosis are asymptomatic. The cause of this microbial alteration in the normal vaginal flora is not understood. While BV is rarely seen in women who have never been sexually active, it is not clear whether the disease is the result of a sexually transmitted pathogen.
Bacterial vaginosis can be diagnosed by the use of clinical and microscopic criteria. The CDC states that for the disease to be diagnosed, three of the following signs or symptoms must be present: (1) a homogeneous, white, noninflammatory discharge that smoothly coats the vaginal walls; (2) presence of clue cells on microscopic examination (epithelial cells coated by bacteria); (3) pH greater than 4.5; and (4) a fishy odor to the discharge after addition of KOH (whiff test). 3 Gram staining, which demonstrates a concentration of bacterial morphotypes characteristic of BV, is an acceptable laboratory method of diagnosing BV. Culture of G. vaginalis is not recommended.3
Research has demonstrated an association between BV and adverse pregnancy outcomes due to preterm labor and premature rupture of membranes (PROM), leading to recommendations that high-risk patients (i.e., those who previously delivered a premature infant) be screened for BV during the second trimester of pregnancy.4 BV has also been associated with pelvic inflammatory disease, endometritis, and vaginal cuff cellulitis after surgical procedures.
Recommendations for treatment are controversial for asymptomatic patients. Several drug regimens are available (T§ble...104z2)3 All symptomatic patients, unless allergic to the drug, should be treated with metronidazole regardless of pregnancy status. 3 Because of the association of BV with postsurgical infection, strong consideration should be given to prophylactic treatment of infected women prior to surgical abortion.
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