CER Microbiology and Infection Control Questions and Answers 4 — Questions and Answers
Question 1: Which reprocessing step has been identified as the single most critical factor in preventing endoscope-related infection transmission?
- High-level disinfection with an FDA-cleared chemical
- Manual cleaning performed immediately after the procedure (Correct answer)
- Automated endoscope reprocessor (AER) final rinse
- Proper drying and storage after reprocessing
Correct answer: Manual cleaning performed immediately after the procedure
Manual cleaning reduces bioburden by up to 4 log10, and inadequate cleaning is the root cause identified in most endoscope-related outbreak investigations.
Question 2: Which of the following organisms requires PRION decontamination protocols rather than standard high-level disinfection?
- Mycobacterium tuberculosis
- Creutzfeldt-Jakob disease (CJD) prion (Correct answer)
- Clostridium difficile
- Carbapenem-resistant Enterobacteriaceae (CRE)
Correct answer: Creutzfeldt-Jakob disease (CJD) prion
CJD prions are not inactivated by standard HLD; dedicated equipment and specific decontamination protocols (e.g., extended autoclaving at 134°C) or instrument destruction are required.
Question 3: An endoscope reprocessing technician notices the MEC test strip for glutaraldehyde solution shows the color is lighter than the reference standard. The correct action is to:
- Continue using the solution because minor variation is acceptable
- Discard the solution and prepare a fresh batch (Correct answer)
- Add more glutaraldehyde concentrate to the existing solution
- Increase the soak time by 50% to compensate for lower concentration
Correct answer: Discard the solution and prepare a fresh batch
A MEC test showing concentration below the minimum effective concentration means the solution cannot provide reliable HLD and must be discarded.
Question 4: What is the primary purpose of flushing all endoscope channels with 70% isopropyl alcohol followed by forced air during the drying step?
- To provide a final antimicrobial kill step before storage
- To remove residual water that supports microbial growth during storage (Correct answer)
- To lubricate internal channel surfaces and prevent cracking
- To neutralize any remaining disinfectant chemical residue
Correct answer: To remove residual water that supports microbial growth during storage
Residual moisture in stored endoscope channels supports rapid microbial proliferation, including Pseudomonas; alcohol aids water displacement and evaporation.
Question 5: Standard precautions in an endoscopy reprocessing area require that staff wear PPE that includes, at minimum:
- N95 respirator, goggles, gown, and double gloves for all tasks
- Gloves only during chemical disinfectant contact
- Gloves, fluid-resistant gown, face shield or mask with eye protection, and appropriate gloves (Correct answer)
- Surgical mask and nitrile gloves for all tasks
Correct answer: Gloves, fluid-resistant gown, face shield or mask with eye protection, and appropriate gloves
OSHA Bloodborne Pathogen Standards and SGNA guidelines require gloves, fluid-resistant gown, and face/eye protection due to splash risk from contaminated scopes and chemicals.
Question 6: Clostridium difficile spores are resistant to most standard disinfectants. Which agent is effective for environmental surface decontamination in areas with C. diff outbreaks?
- Quaternary ammonium compounds (quats)
- 70% isopropyl alcohol
- Sodium hypochlorite (bleach) at appropriate concentration (Correct answer)
- 2% glutaraldehyde
Correct answer: Sodium hypochlorite (bleach) at appropriate concentration
Sodium hypochlorite (bleach) is sporicidal and effective against C. difficile spores; quats and alcohols do not kill spores.
Question 7: Which factor MOST directly determines whether an organism is classified as a 'high-level disinfection-resistant' pathogen?
- Its ability to form spores or highly resistant cellular structures (Correct answer)
- Its gram-negative cell wall composition
- The presence of a lipid envelope protecting the cell membrane
- Its ability to produce exotoxins that inactivate disinfectants
Correct answer: Its ability to form spores or highly resistant cellular structures
Spore formation (e.g., bacterial endospores) confers extreme resistance to chemical disinfectants, placing spore-formers beyond the kill range of HLD agents.
CER Microbiology and Infection Control Questions and Answers 4
Which reprocessing step has been identified as the single most critical factor in preventing endoscope-related infection transmission?