To biologically validate that an autoclave cycle has achieved sterility, the standard biological indicator contains spores of:
- A Geobacillus stearothermophilus ✓
- B Bacillus subtilis var niger
- C Clostridium tetani
- D Bacillus pumilus
Correct answer: A. Geobacillus stearothermophilus
Explanation
Geobacillus stearothermophilus (formerly Bacillus stearothermophilus) spores are the most heat resistant in common use and are killed only by a properly functioning moist heat cycle, making them the biological monitor for autoclaves. Bacillus subtilis var niger spores serve the same role for the hot air oven, and Bacillus pumilis for ionising radiation. Matching the indicator to the process is the tested point.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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