Bacterial vaginosis accounts for 10 to 30 percent of the cases of infectious vaginitis in women of childbearing age.7 In bacterial vaginosis, there is a decrease in normal lactobacilli and a proliferation of Gardnerella vaginalis, Mycoplasma hominis, and anaerobes, including Mobiluncus, Bacteroides, and Peptostreptococcus species.

The Amsel criteria are considered to be the standard diagnostic approach to bacterial vaginosis and continue to be generally reliable.7,8 The criteria are as follows: milky, homogeneous, adherent discharge; vaginal pH greater than 4.5; positive whiff test (the discharge typically has a fishy smell); and presence of clue cells in the vaginal fluid on light microscopy.4 If three of the four criteria are met, there is a 90 percent likelihood of bacterial vaginosis.

Because Gardnerella vaginalis commonly is found in asymptomatic women, vaginal culture is not useful for diagnosing bacterial vaginosis.

The presence of small gram-negative rods or gram-variable rods and the absence of longer lactobacilli on a Gram stain of the vaginal discharge also is highly predictive of bacterial vaginosis.9 However, this method of diagnosis is impractical in most family physicians’ offices. Because G. vaginalis commonly is found in asymptomatic women, culture is not useful.

According to guidelines from the Centers for Disease Control and Prevention (CDC),10 treatment of bacterial vaginosis is indicated to reduce symptoms and prevent infectious complications associated with pregnancy termination and hysterectomy. Treatment also may reduce the risk of human immunodeficiency virus (HIV) transmission.10 Thus, it is reasonable to treat asymptomatic patients who are scheduled for hysterectomy or pregnancy termination or who are at increased risk for HIV infection;10 other asymptomatic patients need not be treated.

Bacterial Vaginosis treatment

The standard treatment for bacterial vaginosis is metronidazole (Flagyl) in a dosage of 500 mg orally twice daily for seven days (Table 2).10 Although other treatments have been shown to have approximately equivalent efficacy,11-16 they are associated with higher recurrence rates. These agents include 0.75 percent metronidazole gel (MetroGel-Vaginal) and 2 percent clindamycin cream (Cleocin). Less effective alternatives include metronidazole in a single 2-g oral dose, oral clindamycin, and intravaginal clindamycin ovules.