Micro & Immunology · single question
Geobacillus stearothermophilus, used as a biological indicator for autoclave (steam) sterilization, is:
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Correct answer: D. Highly resistant and non-pathogenic
- A. Incorrect – it is not a human pathogen.
- B. Incorrect – low resistance would not validate the cycle.
- C. Incorrect – a biological indicator must be HIGHLY resistant to be meaningful.
- D. Correct – its spores are highly heat-resistant (so killing them proves sterilization) yet it is non-pathogenic (safe to handle as a test organism).
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