AP-Micro Microbiology: Sterilization, Disinfection, and Infection Control 2

Question 1

High-level disinfection is defined as a process that eliminates:

Accepted Answer

All microorganisms except bacterial spores

Answer

High-level disinfection kills all microorganisms except high numbers of bacterial endospores; sterilization is required to eliminate spores completely.

Question 2

Which chemical agent is classified as a high-level disinfectant and is commonly used for reprocessing heat-sensitive flexible endoscopes?

Accepted Answer

Glutaraldehyde 2%

Answer

2% glutaraldehyde (e.g., Cidex) is an aldehyde-based high-level disinfectant widely used for endoscope reprocessing when sterilization is not possible.

Question 3

Chlorine-based disinfectants such as sodium hypochlorite exert their antimicrobial activity primarily by:

Accepted Answer

Oxidizing cellular components and denaturing proteins

Answer

Hypochlorite releases hypochlorous acid, a powerful oxidizer that destroys proteins, enzymes, and nucleic acids through oxidation, causing broad-spectrum microbial death.

Question 4

Which antiseptic is preferred for surgical hand scrubs and preoperative patient skin preparation due to its persistent residual antimicrobial activity?

Accepted Answer

Chlorhexidine gluconate

Answer

Chlorhexidine gluconate binds to skin proteins and provides prolonged residual activity lasting several hours after application, making it preferred for surgical antisepsis.

Question 5

Quaternary ammonium compounds (quats) are LEAST effective against which category of microorganisms?

Accepted Answer

Mycobacteria and bacterial endospores

Answer

Quats have low activity against mycobacteria and no sporicidal activity; their cationic surfactant mechanism is ineffective against the waxy mycobacterial cell wall and resistant endospores.

AP Practice Test

AP Practice Test

AP-Micro Microbiology: Sterilization, Disinfection, and Infection Control 2