CST Sterilization & Infection Control 2

Question 1

Which biological indicator organism is used to verify the efficacy of ethylene oxide (EO) sterilization?

Accepted Answer

Bacillus atrophaeus

Answer

Bacillus atrophaeus (formerly B. subtilis var. niger) spores are the standard biological indicator for ethylene oxide sterilization cycles.

Question 2

The term 'bioburden' refers to:

Accepted Answer

The number of viable microorganisms on a device before sterilization

Answer

Bioburden is the total number of viable microorganisms contaminating an item prior to sterilization.

Question 3

A sterile field is considered contaminated when:

Accepted Answer

Moisture soaks through a sterile drape to the surface below

Answer

Strike-through contamination occurs when moisture creates a pathway for microorganisms through a sterile drape to an unsterile surface below.

Question 4

Which sterilization method is most appropriate for heat-labile endoscopes?

Accepted Answer

Low-temperature hydrogen peroxide gas plasma

Answer

Low-temperature hydrogen peroxide gas plasma (e.g., STERRAD) is used for heat-sensitive instruments like flexible endoscopes.

Question 5

The purpose of the pre-vacuum (prevacuum) phase in a dynamic-air-removal steam sterilizer is to:

Accepted Answer

Remove air to allow steam penetration into porous loads

Answer

The prevacuum phase evacuates air from the chamber and load so steam can penetrate porous materials uniformly.

(CST) Certified Surgical Technician Practice Test