- • Grayish-white vaginal discharge.
- • Presence of vaginal epithelial clue cells.
- • Vaginal pH higher than 4.5.
- • Positive “whiff” test.
- • Decreased numbers of lactobacilli.
- • Increased bacteria count, consisting mainly of
short rods observed on wet mount.
Bacterial vaginosis is the most frequent cause of vaginal discharge
in the United States. Symptoms include vaginal discharge and odor,
but half of women with bacterial vaginosis are asymptomatic. Previously
given little attention and called nonspecific vaginitis or Gardnerella vaginitis, bacterial vaginosis
is now known to be significantly associated with complications of pregnancy,
including preterm rupture of membranes, preterm delivery, and low
birth weight. Additionally, it has been associated with gynecologic
complications such as postabortal endometritis, posthysterectomy
vaginal cuff cellulitis, pelvic inflammatory diseases (PID), and urinary
tract infections. It also appears to be a risk factor for acquisition
of sexually transmitted diseases (STDs), including HIV.
The pathogenesis of bacterial vaginosis remains obscure, but
the bulk of the epidemiologic data suggests that the disease is
sexually transmitted. However, understanding of transmission is
limited because the causative agent remains unknown and there is
no clinical correlate of infection or disease in men. In terms of
the microbiologic findings in bacterial vaginosis, lactobacilli,
especially hydrogen peroxide—producing strains, are greatly
diminished and are replaced with large numbers of Gardnerella vaginalis as well as multiple
types of anaerobic bacteria and mycoplasmas. The decline in lactobacilli, which
produce lactic acid, a key component in the maintenance of the normally
low vaginal pH, results in increased vaginal pH. That increase in
pH allows for the overgrowth of anaerobic bacteria, which apparently
coat epithelial cells (“clue cells”) and produce
a grayish-white vaginal discharge. The metabolites from anaerobic
bacteria are rich in amines responsible for the characteristic fishy
Larsson PG, Forsum U. Bacterial vaginosis—a
disturbed bacterial flora and treatment enigma. APMIS
Hillier SL. The complexity of microbial diversity in bacterial
vaginosis. N Engl J Med
The use of condoms appears to be protective against acquisition
of bacterial vaginosis. Although bacterial vaginosis may be an STD,
antimicrobial therapy directed at anaerobic bacteria (eg, metronidazole)
of the male partner has yet to be proved effective. Among women
who have sex with women, examination and treatment of the sex partner
is likely to be of benefit in preventing recurrence in the index
case, because studies have found high concordance rates of bacterial
vaginosis among sex partners in this setting. Twice-weekly prophylactic
use of intravaginal metronidazole has proven to be efficacious in
Symptomatic bacterial vaginosis causes vaginal discharge or odor,
or both. The odor is usually described as fishy and may be more
noticeable after unprotected intercourse or during menses. Half
of women with bacterial vaginosis complain of no symptoms. On examination,
a homogenous, milky discharge adherent to the walls of the vagina