NC Sterilization & Infection Control Exam
2026 | Verified Actual Questions & Correct
Answers with Detailed Rationales | A+
Graded Complete Study Guide for
Certification Success
• This -question verified study guide covers every core domain of the NC
Sterilization & Infection Control Certification exam — microbiology, sterilization
methods, disinfection levels, infection precautions, PPE, monitoring, regulatory
standards, HAIs, and endoscope reprocessing — with confirmed correct answers
and detailed EXPERT RATIONALE for every item.
• Study by attempting each question independently before reading the correct
answer, then reviewing the EXPERT RATIONALE carefully to reinforce
understanding and close knowledge gaps before exam day.
NC STERILIZATION & INFECTION CONTROL EXAM 2026
Verified Actual Questions | Correct Answers | Detailed EXPERT RATIONALE |
A+ Complete Study Guide
Q1. Which microorganism is considered the MOST resistant to sterilization
processes?
A. Staphylococcus aureus
B. Mycobacterium tuberculosis
C. Geobacillus stearothermophilus spores
D. Pseudomonas aeruginosa
E. Hepatitis B virus
✔ Correct Answer: C. Geobacillus stearothermophilus spores
,EXPERT RATIONALE: Bacterial endospores — particularly those of Geobacillus
stearothermophilus — are the most resistant microorganisms to sterilization. This
is precisely why they are used as biological indicators to validate steam sterilization
efficacy.
Q2. Which of the following represents the correct order of microbial
resistance from MOST to LEAST resistant?
A. Spores, mycobacteria, non-enveloped viruses, vegetative bacteria
B. Vegetative bacteria, mycobacteria, spores, viruses
C. Non-enveloped viruses, spores, mycobacteria, vegetative bacteria
D. Mycobacteria, spores, vegetative bacteria, viruses
E. Spores, vegetative bacteria, mycobacteria, non-enveloped viruses
✔ Correct Answer: A. Spores, mycobacteria, non-enveloped viruses, vegetative
bacteria
EXPERT RATIONALE: The correct order from most to least resistant is: prions >
bacterial spores > mycobacteria > non-enveloped (non-lipid) viruses > fungi >
vegetative bacteria > enveloped (lipid) viruses. This hierarchy guides the selection of
appropriate reprocessing levels.
Q3. What is a prion?
A. A small RNA virus without a protein coat
B. An abnormally folded protein that causes neurodegenerative disease and is
highly resistant to conventional sterilization
C. A type of bacterial endospore
D. A parasitic organism smaller than a bacterium
E. A protein-coated DNA fragment
,✔ Correct Answer: B. An abnormally folded protein that causes
neurodegenerative disease and is highly resistant to conventional
sterilization
EXPERT RATIONALE: Prions are infectious, misfolded proteins with no nucleic acid.
They cause diseases such as Creutzfeldt-Jakob disease (CJD) and are extraordinarily
resistant to standard sterilization methods including steam, chemical disinfectants,
and radiation.
Q4. The chain of infection consists of how many links?
A. 3
B. 4
C. 5
D. 6
E. 7
✔ Correct Answer: D. 6
EXPERT RATIONALE: The chain of infection has six links: (1) infectious agent, (2)
reservoir, (3) portal of exit, (4) mode of transmission, (5) portal of entry, and (6)
susceptible host. Breaking any single link interrupts transmission and prevents
infection.
Q5. Which of the following is NOT a mode of transmission in the chain of
infection?
A. Droplet
B. Airborne
C. Contact
D. Reservoir
E. Vehicle
, ✔ Correct Answer: D. Reservoir
EXPERT RATIONALE: The reservoir is a separate link in the chain of infection
(where the pathogen lives and multiplies), not a mode of transmission. Modes of
transmission include contact, droplet, airborne, vehicle-borne, and vector-borne.
Q6. Which type of bacteria forms endospores as a survival mechanism?
A. Gram-negative rods
B. Gram-positive cocci
C. Mycobacteria
D. Gram-positive rods such as Bacillus and Clostridium
E. Spirochetes
✔ Correct Answer: D. Gram-positive rods such as Bacillus and Clostridium
EXPERT RATIONALE: Endospore formation is a characteristic of certain gram-
positive rods — primarily Bacillus and Clostridium species. Endospores are
dormant, highly resistant structures that can survive extreme conditions including
heat, radiation, desiccation, and many disinfectants.
Q7. Mycobacterium tuberculosis is classified as which level of resistance
regarding sterilization?
A. Least resistant
B. Moderately resistant
C. Highly resistant, ranking second only to bacterial spores
D. More resistant than bacterial spores
E. Equal in resistance to vegetative bacteria
✔ Correct Answer: C. Highly resistant, ranking second only to bacterial spores
2026 | Verified Actual Questions & Correct
Answers with Detailed Rationales | A+
Graded Complete Study Guide for
Certification Success
• This -question verified study guide covers every core domain of the NC
Sterilization & Infection Control Certification exam — microbiology, sterilization
methods, disinfection levels, infection precautions, PPE, monitoring, regulatory
standards, HAIs, and endoscope reprocessing — with confirmed correct answers
and detailed EXPERT RATIONALE for every item.
• Study by attempting each question independently before reading the correct
answer, then reviewing the EXPERT RATIONALE carefully to reinforce
understanding and close knowledge gaps before exam day.
NC STERILIZATION & INFECTION CONTROL EXAM 2026
Verified Actual Questions | Correct Answers | Detailed EXPERT RATIONALE |
A+ Complete Study Guide
Q1. Which microorganism is considered the MOST resistant to sterilization
processes?
A. Staphylococcus aureus
B. Mycobacterium tuberculosis
C. Geobacillus stearothermophilus spores
D. Pseudomonas aeruginosa
E. Hepatitis B virus
✔ Correct Answer: C. Geobacillus stearothermophilus spores
,EXPERT RATIONALE: Bacterial endospores — particularly those of Geobacillus
stearothermophilus — are the most resistant microorganisms to sterilization. This
is precisely why they are used as biological indicators to validate steam sterilization
efficacy.
Q2. Which of the following represents the correct order of microbial
resistance from MOST to LEAST resistant?
A. Spores, mycobacteria, non-enveloped viruses, vegetative bacteria
B. Vegetative bacteria, mycobacteria, spores, viruses
C. Non-enveloped viruses, spores, mycobacteria, vegetative bacteria
D. Mycobacteria, spores, vegetative bacteria, viruses
E. Spores, vegetative bacteria, mycobacteria, non-enveloped viruses
✔ Correct Answer: A. Spores, mycobacteria, non-enveloped viruses, vegetative
bacteria
EXPERT RATIONALE: The correct order from most to least resistant is: prions >
bacterial spores > mycobacteria > non-enveloped (non-lipid) viruses > fungi >
vegetative bacteria > enveloped (lipid) viruses. This hierarchy guides the selection of
appropriate reprocessing levels.
Q3. What is a prion?
A. A small RNA virus without a protein coat
B. An abnormally folded protein that causes neurodegenerative disease and is
highly resistant to conventional sterilization
C. A type of bacterial endospore
D. A parasitic organism smaller than a bacterium
E. A protein-coated DNA fragment
,✔ Correct Answer: B. An abnormally folded protein that causes
neurodegenerative disease and is highly resistant to conventional
sterilization
EXPERT RATIONALE: Prions are infectious, misfolded proteins with no nucleic acid.
They cause diseases such as Creutzfeldt-Jakob disease (CJD) and are extraordinarily
resistant to standard sterilization methods including steam, chemical disinfectants,
and radiation.
Q4. The chain of infection consists of how many links?
A. 3
B. 4
C. 5
D. 6
E. 7
✔ Correct Answer: D. 6
EXPERT RATIONALE: The chain of infection has six links: (1) infectious agent, (2)
reservoir, (3) portal of exit, (4) mode of transmission, (5) portal of entry, and (6)
susceptible host. Breaking any single link interrupts transmission and prevents
infection.
Q5. Which of the following is NOT a mode of transmission in the chain of
infection?
A. Droplet
B. Airborne
C. Contact
D. Reservoir
E. Vehicle
, ✔ Correct Answer: D. Reservoir
EXPERT RATIONALE: The reservoir is a separate link in the chain of infection
(where the pathogen lives and multiplies), not a mode of transmission. Modes of
transmission include contact, droplet, airborne, vehicle-borne, and vector-borne.
Q6. Which type of bacteria forms endospores as a survival mechanism?
A. Gram-negative rods
B. Gram-positive cocci
C. Mycobacteria
D. Gram-positive rods such as Bacillus and Clostridium
E. Spirochetes
✔ Correct Answer: D. Gram-positive rods such as Bacillus and Clostridium
EXPERT RATIONALE: Endospore formation is a characteristic of certain gram-
positive rods — primarily Bacillus and Clostridium species. Endospores are
dormant, highly resistant structures that can survive extreme conditions including
heat, radiation, desiccation, and many disinfectants.
Q7. Mycobacterium tuberculosis is classified as which level of resistance
regarding sterilization?
A. Least resistant
B. Moderately resistant
C. Highly resistant, ranking second only to bacterial spores
D. More resistant than bacterial spores
E. Equal in resistance to vegetative bacteria
✔ Correct Answer: C. Highly resistant, ranking second only to bacterial spores
