Which organism is often used as an indicator for testing the effectiveness of steam sterilization?

Bacillus stearothermophilus is widely recognized as a reliable biological indicator for assessing the effectiveness of steam sterilization. This organism is a spore-forming bacterium that is highly resilient to heat, making it an ideal candidate for testing sterilization processes. The spores of Bacillus stearothermophilus are capable of surviving the high temperatures employed in steam sterilization, which means that if these spores are not killed during the process, it indicates a potential failure of the sterilization cycle.

When steam sterilization is conducted, the spores should be destroyed, and this can be verified through culture methods. If the spores do not grow after exposure to the sterilization process, it confirms that the steam sterilization was effective in eliminating these resistant spores. Because of this attribute, Bacillus stearothermophilus is often used in quality control settings to ensure that autoclaves and other steam sterilization devices are functioning correctly.

Other organisms mentioned in the options do not possess the same qualities for this specific application. Bacillus subtilis, while it can also serve as a biological indicator, is not as resistant to heat as Bacillus stearothermophilus and is typically not used for steam sterilization monitoring. Escherich