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What are Biological Indicators for Autoclaves

Published: 2021-05-24
What are Biological Indicators for Autoclaves
What are Biological Indicators for Autoclaves

Sterilization is an essential procedure in the medical world. Its goal is to destroy and eliminate potential contaminants in the products and ensure that the pieces of equipment are contamination-free and safe to use by anyone.

Indicators are used to assist in determining if the sterilization process has appropriately worked in meeting the conditions needed for effective sterilization to occur. Two indicators are being used in validating the effectiveness and efficiency of steam sterilization or autoclaving. They are the chemical and the biological indicators.

Difference Between Chemical (CIs) and Biological Indicators (BIs)

Both the chemical and biological indicators are validating tools of the autoclaving process. Their function is to test and monitor if the sterilization capabilities of the autoclaves are doing well. They make sure that the autoclave is performing correctly as a sterilization instrument.

Though they are both steam sterilization indicators, they still differ in some areas. Biological indicators are used to ensure that the autoclave's chamber is highly and wholly saturated during the sterilization process. On the other hand, the chemical indicators are used to ensure that the pieces of equipment are getting the required amount of steam for successful sterilization.

Biological Indicators (BIs) in Autoclave Validation

Nature and Use

As mentioned earlier, biological indicators validate tools used in confirming the practical function of autoclave sterilization. In addition, viable microorganisms make up the biological indicators. These microorganisms are sterilization resistant that helps monitor if the required sterilization conditions are met in eliminating the unwanted microbes present.

Application and Result

The bacterial spores, or the endospores, are the primary microorganisms used in BIs because they can withstand the high-level sterilization process. The Geobacillus Stearothermophilus (GS) spores and the Bacillus Atrophaeus (BA) are some of the toughest microorganisms used as indicators. The GS spores are used in the sterilization process that involves steam and vaporized state of hydrogen peroxide. On the other hand, BA is used in sterilization that applies dry heat and ethylene oxide (EO) to the process.

A positive result of the biological indicator demonstrates that the sterilizer can effectively kill many highly resistant bacterial spores. With the use of this indicator, users can feel sure of the sterilization process.

Effectivity Validation

The Association Advancement of Medical Instrumentation (AAMI) has considered the use of biological indicators as "the cornerstone for the quality assurance program of the sterilization process." The proof-positive way of the BIs in confirming the elimination of the microbial contaminants is way ahead of the monitoring done with chemical and mechanical indicators. Thus, BI is more reliable compared to other indicators available.

Final Thoughts

Biological indicators used in an autoclave or steam sterilization prove to be effective in validating the success of the sterilization process. The daily use of BIs is an effective way to identify early malfunctions and errors, thus significantly reducing the patient risk of contamination.

Indeed, the accuracy of BIs using spore strips in validating the deadliness of steam sterilization is more reliable and controllable than other indicators available in the medical world.

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