Monitoring & QAQuestion 59 of 100

Which organism is used in biological indicators for steam sterilization, and why?

a.Geobacillus stearothermophilus, because its spores are highly resistant to moist heat
b.Bacillus atrophaeus, because its spores are highly resistant to moist heat
c.Clostridioides difficile, because it is a common healthcare pathogen
d.Staphylococcus aureus, because it survives on dry surfaces

Explanation

Biological indicators use a highly resistant spore population that is harder to kill than the microorganisms found on devices, and Geobacillus stearothermophilus fills that role for steam, hydrogen peroxide, and ozone. Bacillus atrophaeus is used for ethylene oxide and dry heat. Vegetative pathogens such as staphylococci and clinical spore formers such as C. difficile are far less resistant and are never used as process challenge organisms.

Law Reference: AAMI ST79

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