Which pair correctly matches the sterilization method with the biological indicator organism recommended for monitoring it?
- A Hot air oven: Geobacillus stearothermophilus
- B Autoclave: Bacillus pumilus
- C Ethylene oxide: Bacillus atrophaeus (subtilis) ✓
- D Ionizing radiation: Clostridium sporogenes
Correct answer: C. Ethylene oxide: Bacillus atrophaeus (subtilis)
Explanation
Ethylene oxide sterilization is monitored with spore strips of Bacillus atrophaeus (formerly C. subtilis var niger), which has high resistance to this gas. The standard indicator for autoclaving is Geobacillus stearothermophilus, for hot air ovens and ionizing radiation it is Bacillus atrophaeus, and for filtration testing it is Pseudomonas diminuta or Brevundimonas diminuta.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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