Which of the following is used to test the efficiency of sterilization in an autoclave?
A. Clostridium tetani
B. Bacillus stearothermophilus
C. Bacillus pumilus
D. Bacillus subtilis
(Modified repeat question – AIIMS Nov 10 – AA q67)
Correct answer : B. Bacillus stearothermophilus
Biological Indicator Monitoring of autoclaves – Operators must use the biological indicator Bacillus stearothermophilus placed at the center of a load processed under standard operating conditions at least monthly to confirm the attainment of adequate sterilization conditions.
- Use spore ampules or strips with an average population of 104 to 106 organisms adjusted to the following resistance data – survives steam heat at 250º F for five minutes and is killed at 250º F in thirteen minutes.
- The most reliable means for determining whether a sterilizing cycle has been successful is by planting biological indicators throughout the load before the load is subjected to the sterilization process.
- Operate the autoclave in accordance with manufacturer’s instruction. The cycle (time and temperature) shall be the minimum as required by user’s lab procedures.
- Record chamber temperature as shown by the sterilizer indicator autoclave’s thermometer.
- Upon completion of cycle, fast exhaust the chamber and remove test spore strips from the autoclave.
- Incubate the Bacillus stearothermophilus test strips according to manufacturer’s instructions.
- Record results on the Quality Control Checklist