Bacterium
Gardnerella vaginalis
Clue-cell bacterial vaginosis rod
gard-nuh-REL-uh vaj-ih-NAH-lis
High-yield clue
Clue cells (vaginal epithelial cells coated with bacteria) plus a positive amine 'whiff' test and elevated vaginal pH are the classic bacterial vaginosis clues.
Overview
A pleomorphic, gram-variable facultative anaerobe that is the main marker organism of bacterial vaginosis, a polymicrobial overgrowth. It is the standard teaching example of 'clue cells'.
Classification
- Gram-variable
- Pleomorphic rod/coccobacillus
- Facultative anaerobe
- Non-motile
Lab & identification clues
- Clue cells on wet mount
- Gram-variable pleomorphic staining
- Positive amine (whiff) test with KOH
- Elevated vaginal pH above 4.5
Associations
- Bacterial vaginosis
- Loss of protective lactobacilli
- Polymicrobial overgrowth with anaerobes
Commonly confused with
- Trichomonas vaginalis
- Candida vulvovaginitis
Your notes
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.