VAGINITIS I—TRICHOMONAS, MONILIA,
BACTERIAL VAGINOSIS
The vaginal flora has many different types of bacteria, some of which, like lactobacilli, are necessary for normal vaginal metabolism and for maintenance of the vaginal pH at the normal level of 3.8 to 4.2. Also present in numbers, which may be altered by such conditions as age, debility, systemic disease, ovulation, menstruation, and pregnancy are a variety of potentially pathogenic organisms. Among these are streptococci, staphylococci, colon bacilli, and fungi.
Bacterial vaginitis is a vaginal infection caused by an overgrowth of
normal or pathogenic bacteria that results in irritation, inflammation, and
clinical symptoms. Bacterial vaginosis is a change in vaginal ecology caused by
an overgrowth of anaerobic bacteria, often with an absence of clinical
symptoms. It should be noted that bacterial vaginosis does not engender an
inflammatory response and is therefore technically not a type of vaginitis.
Bacterial vaginosis is a polymicrobial process that involves the loss of normal
lactobacilli, an increase in anaerobic bacteria (especially Gardnerella
vaginalis, Bacteroides spp., Peptococcus spp., and Mobiluncus
spp.), and a change in the chemical composition of the vaginal secretions.
There is a 1000-fold increase in the number of bacteria present and a 1000 : 1
anaerobic/ aerobic bacteria ratio (normal 5 : 1), high levels of mucinases;
phospholipase A2, lipases, proteases, arachidonic acid, and
prostaglandins are all present. Amines (cadaverine and putrescine) are made
through bacterial decarboxylation of arginine and lysine. These amines are more
volatile at an alkaline pH, such as that created by the addition of 10% KOH or
semen (roughly a pH of 7), giving rise to the odor found with the “whiff test”
or reported by these patients after intercourse.
The second most common type of specific vaginal infection is due to fungal
organisms. These are ubiquitous fungi found in the air or as common inhabitants
of the vagina, rectum, and mouth. The most common species responsible are Candida
albicans (80% to 95%), Candida glabrata, Candida tropicalis,
or others (5% to 20%). These infections are more common when there is an
altered vaginal ecosystem (stress, antibiotic use, pregnancy, diabetes,
depressed immunity, topical con- traceptives, and warm and moist environment).
The diagnosis is established by clinical examination and demonstration of the
branching, club-shaped filaments in an unstained, wet preparation. Cultures
(Nickerson or Sabouraud media) or monoclonal antibody staining may be obtained
but are seldom necessary. Clinically, the infection causes an aphthous
ulcerative infection with a patchy, white exudate, which leaves a raw, bleeding
surface when it is removed. The discharge may be thick or watery and is
irritating to the external surfaces.
Infections caused by Trichomonas vaginalis, a protozoan parasite, are found in approximately 25% of gynecologic patients. Trichomonas is a fusiform protozoon slightly larger than a white blood cell with three to five flagella, which provide active movement, extending from the narrow end. On examination, the vaginal walls are red and edematous with small petechial hemorrhages, producing the so-called strawberry appearance. The thin, greenish-yellow discharge contains many small bubbles, giving it a foamy appearance, which is almost pathognomonic. The discharge is irritating to the external genitalia and causes severe burning and itching. Diagnosis is established by physical examina- tion and microscopic examination of vaginal secretions in normal saline (sensitivity of 60% to 70%). Culture or monoclonal antibody testing may be obtained but is seldom necessary. Evaluation for concomitant sexually transmissible infections should be strongly considered. Food and Drug Administration–cleared tests for tricho- moniasis in women include OSOM Trichomonas Rapid Test, an immunochromatographic capillary flow dipstick technology, and a nucleic acid probe test that evaluates for T. vaginalis, G. vaginalis, and C. albicans. These tests have a sensitivity >83% and a specificity >97%
