Gardnerella vaginalis refers to an infection of the female genital tract caused by bacteria from the Gardnerella vaginalis strain, often accompanied by various anaerobic bacteria. This condition is commonly known as bacterial vaginosis.
G. vaginalis is characterized as a facultatively anaerobic Gram-variable coccobacilli that do not form spores or exhibit motility. It was first identified in 1955 by Gardner and Dukes.
Typically, this infection results in a gray or yellow discharge with a distinctive "fishy" odor, which tends to intensify following the use of alkaline soaps for genital hygiene.
Gardnerella vaginalis represents the predominant cause of bacterial vaginitis among sexually active adult women. Patients typically present with a malodorous discharge that is non-irritating, often accompanied by homogenous gray-white secretions. Upon application of 10 percent potassium hydroxide to vaginal secretions on a glass slide, a transient "fishy odor" may be detected.
Causes of Gardnerella Vaginalis
The infection is believed to be primarily sexually transmitted. However, Gardnerella vaginalis can also be found in women without a history suggestive of sexually transmitted diseases, often without any accompanying symptoms.
Symptoms of Gardnerella Vaginalis
Symptoms commonly include vaginal discharge characterized by a "musty" or "fishy" odor. The volume of discharge can vary, and there is typically minimal irritation of the vulva or vagina associated with this infection, with the pungent odor being the predominant complaint.
Diagnosis of Gardnerella Vaginalis
Diagnosis involves examining a wet mount preparation of physiological saline mixed with vaginal secretions under low-power and high-power microscopy. Typically, there are few white blood cells and lactobacilli present. The diagnostic hallmark is the identification of "clue cells," which are epithelial cells characterized by stippling or granulation due to adherent G. vaginalis organisms.
Clusters of G. vaginalis organisms may also be observed adhering to the edges of epithelial cells or floating freely in the preparation. Cultures are rarely necessary for confirming the diagnosis.
Treatment of Gardnerella Vaginalis
The preferred treatment for Gardnerella vaginalis is oral metronidazole, administered at 500 mg twice daily for six days. In adolescents, a single 2 g dose has proven effective, though generally, a treatment course lasting five to seven days is more efficacious.
While simultaneous treatment of sexual partners is recommended, its effect on reducing recurrence rates remains uncertain. Contraindications to metronidazole include specific blood disorders and central nervous system diseases, with alcohol intolerance being a notable side effect. The drug is contraindicated during early pregnancy and lactation.
Alternatively, oral cephradine at 500 mg four times daily for six days can eliminate Gardnerella vaginalis from the vagina and alleviate symptoms, but it has minimal impact on the vaginal anaerobic flora.
Various oral and vaginal preparations have been prescribed, but their efficacy has been limited. Douching provides temporary relief from malodorous secretions but does not cure the infection.