Bacterium
Ureaplasma urealyticum
Cell-wall-free urease-positive genital mycoplasma
yoor-ee-uh-PLAZ-muh yoor-ee-uh-LIT-ih-kum
High-yield clue
Has no cell wall and is urease-positive (splits urea to ammonia); it is not seen on Gram stain and is inconsistently linked to nongonococcal urethritis, unlike the established agents C. trachomatis and M. genitalium.
Overview
A tiny member of the Mollicutes (family Mycoplasmataceae) that lacks a cell wall and hydrolyzes urea. It is the classic teaching example of a cell-wall-free genital colonizer with an inconsistent role in nongonococcal urethritis.
Classification
- Mollicutes (Mycoplasmataceae)
- No cell wall
- Urease-positive
- Sterol-containing membrane
- Among the smallest free-living bacteria
Lab & identification clues
- No cell wall (beta-lactams irrelevant vocabulary)
- Urease-positive
- Tiny 'T-strain' colonies
- Requires special enriched media
Associations
- Nongonococcal urethritis vocabulary (uncertain etiologic role)
- Genital and perinatal colonization
- Does not take up Gram stain
Commonly confused with
- Mycoplasma genitalium
- Chlamydia trachomatis
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.