Infection Control · single question
Which bacteria is most commonly isolated from dental unit waterline (DUWL) biofilms?
Show answer and explanation
Correct answer: B. Pseudomonas aeruginosa
Pseudomonas aeruginosa is the most commonly isolated organism from dental unit waterline biofilms. It is a gram-negative opportunistic pathogen that thrives in moist environments and forms robust biofilms on the interior surfaces of narrow waterline tubing. It poses risk primarily to immunocompromised patients.
- A. ❌ M. tuberculosis is airborne; does not colonize dental waterlines.
- B. ✅ Pseudomonas aeruginosa — most common DUWL biofilm organism; thrives in moist, stagnant water.
- C. ❌ Legionella can contaminate large water systems but is less commonly cited than Pseudomonas for DUWLs.
- D. ❌ S. mutans is the primary caries pathogen — not a waterline biofilm organism.
Practice Infection Control questions Infection Control study notes