Which bacterial species is used to check the adequacy of autoclaving?

Bacillus stearothermophilus is commonly used as a biological indicator for checking the effectiveness of autoclaving. This bacterial species is thermophilic, meaning it thrives at high temperatures, making it a suitable choice for testing sterilization processes. When autoclaving materials, which involves exposing them to steam at high temperatures and pressure, the goal is to achieve a temperature and time combination sufficient to kill all microorganisms, including spores.

The spores of Bacillus stearothermophilus are particularly resistant to heat and require specific conditions to be destroyed. If the spores survive the autoclave cycle, it indicates that the autoclaving process was inadequate and that some microorganisms may remain viable. Therefore, a successful autoclave cycle will result in the destruction of these spores, confirming that the items sterilized are free of viable microorganisms.

Utilizing this specific organism as a biological indicator is an established practice in laboratory and clinical settings to ensure equipment is functioning correctly and that sterilization protocols are effective. Other bacterial species mentioned do not serve the same purpose or possess the necessary heat resistance characteristics for this specific application.