Microbiology Bacillus used to test the efficacy of Sterilization by Autoclave is? A Bacillus subtilis. B Bacillus pumilus C Bacillus stearothermophilus D Coxiella burnetii 💡 Explanation Bacillus used to test the efficacy of Sterilization by Autoclave is? ✓ Correct Answer: C. Bacillus stearothermophilus