Biological control used in an autoclave is the spore of:

UPUMS Nsg officer-2023

Applied Microbiology & Infection control

Easy

Appeared in: UPUMS Nsg officer-2023

Explanation

Bacillus stearothermophilus is a thermophilic (heat-loving) bacterium, meaning it thrives at high temperatures.
Its endospores are extremely resistant to moist heat, making them the gold standard for testing the effectiveness of steam sterilization (autoclaving).
The principle is that if the autoclave cycle can kill the highly resistant spores of B. stearothermophilus, it is guaranteed to have killed all less-resistant pathogenic microbes.
The test involves placing a vial of these spores in the autoclave, then incubating it. No growth confirms successful sterilization.

Option B: Clostridium perfringens is a pathogenic bacterium that causes serious infections like gas gangrene and food poisoning. It is a microbe to be destroyed by sterilization, not used to test it.
Option C: While Bacillus cereus is a spore-forming bacterium, its spores are significantly less heat-resistant than those of B. stearothermophilus. Using it as an indicator would not provide adequate assurance of sterility.
Option D: Clostridium histolyticum is another pathogenic species of Clostridium, known for producing enzymes that break down tissues. It is not used for sterilization monitoring.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biological indicators for sterilization as background academic context rather than a clinical decision trigger.
Ensuring the effectiveness of sterilization is a cornerstone of infection control in healthcare, directly preventing healthcare-associated infections (HAIs), especially surgical site infections (SSIs).
Nurses are responsible for ensuring that equipment used for patient care is sterile. This includes checking the chemical indicators on packs and understanding the facility's policy on biological monitoring.
What if? If a biological indicator test comes back positive (meaning sterilization failed), the immediate nursing action is to quarantine all items from that load. The items must be repackaged and re-sterilized, and the autoclave must be taken out of service for inspection and repair.

How to Approach the Question

First, identify the key terms in the question: 'biological control' and 'autoclave'.
Recall that an autoclave uses steam under pressure for sterilization.
Understand that a 'biological control' or 'indicator' must be an organism that is more resistant to the sterilization method than the pathogens you want to kill.
For steam sterilization (autoclave), the standard indicator is a highly heat-resistant, non-pathogenic spore-former.
Evaluate the options. Recall or deduce that Bacillus stearothermophilus is the thermophile used for this purpose. The other options are known pathogens, making them unsuitable as indicators.

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