<prompt> Bacillus used to test efficacy of Sterilisation by Autoclave is?Bacillus subtilis.Bacillus pumilis.Bacillus stearothermophilusCoxiella burnetti.  <response>: ANSWER: C Bacillus stearothermophilusREF: Basic medical laboratory techniques 4th edition by Barbara H. Estridge, Anna P. Reynolds,Norma J. Walters Page 70Various bacilli are used to check efficacy of sterilisation methods are:Autoclave- Bacillus stearothermophilusHot air oven- Bacillus subtilis subspecies nigerIonising radiation- Bacillus pumilis 