This module provides an overview of normal vaginal flora, common causes of vaginitis, and general information on the diagnosis and evaluation of vaginitis. The module covers
Bacterial Vaginosis (BV)
Vulvovaginal Candidiasis (VVC)
The vagina is a dynamic ecosystem that normally contains approximately 109 bacterial colony-forming units per gram of vaginal fluid.
The normal vaginal discharge is clear to white, odorless, and of high viscosity.
The normal bacterial flora is dominated by lactobacilli, but a variety of other organisms, including some potential pathogens, are also present at lower levels.
Lactobacilli convert glycogen to lactic acid.
Lactic acid helps to maintain a normal acidic vaginal pH of 3.8 to 4.2.
The acidic environment and other host immune factors inhibit the overgrowth of bacteria and other organisms with pathogenic potential.
Some lactobacilli also produce hydrogen peroxide (H2O2), a potent microbicide that kills bacteria and viruses.
Vaginitis can be characterized by any of the following—vaginal discharge, vulvar itching, vulvar irritation, vaginal odor, dyspareunia, and dysuria.
The three most common types of vaginitis are—bacterial vaginosis (40%–45%), and vulvovaginal candidiasis (20%–25%), trichomoniasis (15%–20%). In some cases the etiology may be mixed, and there may be more than one disease present.
Causes of Vaginitis
Causes of vaginal discharge or irritation may include
Image: Saline: 40x objective. Note lactobacilli and squamous epithelial cells.
Other Diagnostic Aids for Vaginitis Evaluation
Culture—Available for both T. vaginalis and Candidaspp. Culture may be useful in the management of persistent or recurrent vulvovaginal candidiasis. Culture for T. vaginalis is more sensitive than wet mount. Culture for bacterial vaginosis is not recommended.
DNA probe—(BD, Affirm VP III) for Trichomonas vaginalis, Candida albicans, and Gardnerella vaginalis is available. Sensitivity, specificity, and clinical utility are higher than wet mount but lower than culture.
Rapid antigen test—(OSOM TV, Genzyme Diagonostics, Inc.) for T. vaginalis is an available point-of-care test. Sensitivity higher than wet mount, but similar to culture.
Nucleic acid amplification tests (NAAT)—The Trichomonas APTIMA test (GenProbe) is approved by the U.S. FDA for the diagnosis of vaginal trichomoniasis. This test is highly sensitive and specific and can be performed on self-collected or clinician-collected vaginal swab, urine, or liquid endocervical cytology media. This test is considerably more sensitive than culture.
Other commercially available diagnostic tests
PIP activity (Proline aminopeptidase ) for BV
BV-Blue® (Genzyme Diagnostics, Inc.) detects sialidase produced by G. vaginalis and other species for BV
PCR assay—(Amplicor, Roche Diagnostic Corp.) for N. gonorrhoeae, C. trachomatis and T. vaginalis