Micro & Immunology · single question
Which microorganism is spread through aerosolized droplets in saliva?
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Correct answer: C. Mycobacterium tuberculosis
Mycobacterium tuberculosis is transmitted via aerosolized respiratory droplets (airborne transmission). The bacteria are expelled when an infected person coughs, sneezes, or speaks, and can remain suspended in air for hours. This is why TB patients require airborne precautions (N95 respirators) in dental settings. The other organisms have different transmission routes.
- A. INCORRECT. Clostridium botulinum causes botulism through ingestion of preformed toxin (foodborne) or wound infection — not airborne droplets.
- B. INCORRECT. Borrelia burgdorferi causes Lyme disease and is transmitted via tick bites (Ixodes tick), not aerosolized droplets.
- C. CORRECT. Mycobacterium tuberculosis is the classic airborne pathogen in dentistry. It is spread via respiratory aerosols and requires N95 respirators and airborne precautions.
- D. INCORRECT. Treponema pallidum causes syphilis and is transmitted through direct contact with infectious lesions (sexual contact or oral lesions) — not aerosolized droplets.
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