Bacterial vaginosis is polymicrobial in origin and caused by changes in the normal vaginal flora. It primarily affects reproductive-age women and is associated with sexual activity, although transmission is not fully understood. Risk factors include multiple sexual partners, a new sexual partner, non-white race, previous pregnancy, intrauterine device, and use of douches. There is a reduction of hydrogen peroxide-producing lactobacilli and an increased growth of Gardnerella vaginalis and gram-negative anaerobes such as Mycoplasma hominis, Prevotella species, Peptostreptococcus species, Bacteroides, and Mobiluncus. An increased production of amines and alkalinization of the vaginal discharge create the characteristic fishy odor.
Clinically, patients complain of an increased volume of foul-smelling vaginal discharge that is off-white, thin, and homogenous. Many women remain asymptomatic. Uncommonly, patients describe accompanying irritation. Vaginal secretions are characterized by a lack of lactobacilli with a resulting alkaline pH, as well as normal number of white blood cells (hence the term "vaginosis" rather than "vaginitis," denoting the lack of inflammation). The characteristic fishy odor is especially noticeable in the presence of an alkaline substance, such as semen or 10% KOH added to vaginal fluid (the "whiff" test). Another hallmark is the presence of clue cells, epithelial cells studded with bacteria that obscure the sharp margins of the cell, leaving ragged borders.
The differential diagnosis includes any cause of vaginitis, including candidiasis, atrophic vaginitis, bacterial vaginitis, desquamative inflammatory vaginitis, trichomonas, and erosive skin diseases such as lichen planus. The diagnosis is made by the presence of a noninflammatory thin vaginal discharge that adheres to the vaginal wall, a vaginal pH more than 4.5, a positive whiff test, the presence of clue cells on wet mount, and a lack of lactobacilli and signs of inflammation.
Bacterial vaginosis facilitates transmission of HIV and other sexually transmitted diseases (29). In addition, vaginal shedding of HIV is increased in the presence of bacterial vaginosis (30). Several studies have shown that bacterial vagi-nosis is associated with an increase in premature labor, low-birth-weight infants, and chorioamnionitis. Bacterial vaginosis has also been linked with pelvic inflammatory disease, endometritis, posthysterectomy vaginal cuff cellulitis, and postpartum fever. Currently, there is no recommendation to treat male sexual partners.
Table 1G Bacterial Vaginosis
Increased thin Trichomonas adherent discharge, clue cells seen under microscope vaginitis, atrophic vaginitis, vulvovaginal candidiasis
Oral metroni-dazole, topical metronidazole gel, 2% clindamycin cream
The therapy of bacterial vaginosis includes oral metronidazole 500 mg b.i.d. for a week or 2 g once, or clindamycin cream 2% h.s. at bed time daily for 7 days, or orally 300 mg b.i.d. for three to five days. Recurrence is common, and more prolonged suppression is sometimes useful (Table 10).
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The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.