Gardnerella vaginalis


Gardnerella vaginalis:

  • Gram-variable-staining rod, facultative anaerobic bacteria (actually has a Gram-positive cell wall, but because the cell wall is so thin it can appear either Gram-positive or Gram-negative under the microscope).
  • Small (1-1.5 µm diameter) non-spore forming, non-motile coccobacilli.
  • Previously classified as Haemophilus vaginalis and afterwards as Corynebacterium vaginalis.
  • Growth: grows as small, circular, convex, gray colonies on chocolate agar; it also grows on HBT agar.
  • Can cause bacterial vaginosis in some women as a result of a disruption in the normal vaginal microflora. 
  • Typically isolated in genital cultures.  May also be detected in other samples from blood, urine, and pharynx.


Important considerations:  The choice of an agent should be based on local antimicrobial sensitivities, site of infection, cost, and comorbid conditions.   Generally, the most common agents/regimens are listed first.

  1. Metronidazole 500 mg orally twice daily x 7 days
  2. Metronidazole gel 0.75 percent  (one applicatorful ) intravaginally once or twice daily for five days.  If administered once daily, use at bedtime.
  3. Clindamycin 2% cream (Cleocin ®)   (one full applicator) intravaginally at bedtime for 3 or 7 days in nonpregnant patients or for 7 days in pregnant patients 
    Insert one ovule (suppository – 100 mg clindamycin) intravaginally  at bedtime x 3 days.
  4. Clindamycin 300 mg orally twice daily x 7 days
  5. Tinidazole 2 grams orally x 2 days OR  Tinidazole 1 gram orally once daily x 5 days
Gardnerella vaginalis