1. The best method for sterilization is—
a) Hot air oven
b) Boiling
c) Autoclaving
d) Flaming
Answer: Autoclaving
Explanation: Autoclaving uses steam under pressure (121°C, 15 psi) which kills all microorganisms including spores—so it is the most effective sterilization method.
2. The absence of bacteria, viruses and other microorganisms is called—
a) Infection
b) Antisepsis
c) Disinfection
d) Asepsis
Answer: Asepsis
Explanation: Asepsis means complete absence of microorganisms. It is the goal of sterilization in OT and invasive procedures.
3. Spores are killed by—
a) Pasteurization
b) Boiling
c) Autoclaving
d) Disinfection
Answer: Autoclaving
Explanation: Bacterial spores are highly resistant. Only sterilization methods like autoclaving can destroy them completely.
4. Which bacteria do not destroy without autoclave?
a) Aerobic bacteria
b) Anaerobic bacteria
c) Spore-bearing bacteria
d) Rod-shaped bacteria
Answer: Spore-bearing bacteria
Explanation: Spore-forming bacteria (e.g., Clostridium) are resistant to normal disinfection and require sterilization like autoclaving.
5. Which of the following is a method of sterilization?
a) Boiling
b) Disinfection
c) Antisepsis
d) Asepsis
Answer: Boiling
Explanation: Boiling is a physical method that kills most microorganisms but not spores, so it is considered partial sterilization (sometimes categorized under disinfection in strict terms).
6. Disinfection means—
a) Killing all microorganisms including spores
b) Killing pathogenic microorganisms except spores
c) Only cleaning visible dirt
d) Preventing infection only
Answer: Killing pathogenic microorganisms except spores
Explanation: Disinfection reduces harmful microorganisms but does not eliminate spores, unlike sterilization.
7. Antisepsis refers to—
a) Sterilization of instruments
b) Use of chemicals on living tissue
c) Destruction of all microbes
d) Cleaning of environment
Answer: Use of chemicals on living tissue
Explanation: Antiseptics (e.g., iodine, alcohol) are used on skin or wounds to prevent infection.
8. Which method is used for heat-sensitive materials?
a) Autoclaving
b) Boiling
c) Chemical disinfection
d) Flaming
Answer: Chemical disinfection
Explanation: Heat-sensitive items (like plastic equipment) cannot tolerate high temperature, so chemical disinfectants are used.
9. Best method of destroying bacterial spore is—
a) Boiling
b) Autoclaving
c) Hot air oven
d) Flaming
Answer: Autoclaving
Explanation: Bacterial spores are highly resistant to standard heat and chemicals. Autoclaving (moist heat under pressure) is the most reliable method because it reaches temperatures above (typically for 15 minutes), which is necessary to penetrate and destroy the spore coat.
10. A nurse caring for a patient with an infectious disease who requires isolation should refer to guidelines published by the—
a) National league for nursing
b) Centers for Disease Control (CDC)
c) American Medical Association
d) American Nurses Association
Answer: Centers for Disease Control (CDC)
Explanation: The CDC provides the evidence-based guidelines for "Standard Precautions" and "Transmission-Based Precautions" (Isolation). These protocols are essential in clinical settings to prevent the cross-contamination of pathogens between patients and healthcare workers.
11. Best preservation method of milk is—
a) Drying
b) Pasteurization
c) Not boiling
d) By chemical
Answer: Pasteurization
Explanation: Pasteurization is a specific heat-treatment process (a form of disinfection) used to kill pathogenic microorganisms in milk. It ensures the milk is safe for consumption while preserving its nutritional value better than high-heat boiling or chemical additives.
12. What are the most likely caused of urinary tract infection?
a) Staphylococcus aureus
b) Escherichia coli-enterococci
c) Neisseria gonorrheac
d) Streptococcus beta hemolytic
Answer: Escherichia coli-enterococci
Explanation: In the context of infection control, E. coli is the most common cause of healthcare-associated UTIs. Proper aseptic technique during catheterization and perineal hygiene are the primary disinfection/prevention measures used to reduce this risk.
13. Physical methods of sterilization are —
a) Boiling
b) Gas
c) Liquid
d) Oil
Answer: Boiling
Explanation: Sterilization methods are broadly classified into Physical and Chemical. Physical methods include heat (moist heat like boiling and autoclaving, or dry heat like a hot air oven), radiation, and filtration. Chemical methods involve the use of gases (like Ethylene Oxide) or liquids (like Glutaraldehyde/Cidex). Since options b and c are chemical categories, boiling is the correct physical method listed.
14. Most effective methods of sterilization is—
a) Boiling
b) Autoclaving
c) Drying
d) Rinse
Answer: Autoclaving
Explanation: While boiling and drying are physical methods, autoclaving is the most effective because it uses saturated steam under high pressure to reach temperatures (typically ) that kill all forms of microbial life, including highly resistant bacterial spores.
15. Which of the following is considered as the most important aspect of hand washing?
a) Soap
b) Water
c) Friction
d) Time
Answer: Friction
Explanation: In the process of hand disinfection, friction is the most critical element. The mechanical action of rubbing hands together physically loosens and removes dirt, oils, and transient microorganisms from the skin surface so they can be rinsed away.
16. Which is more effective for infection prevention?
a) Isolation
b) Face mask
c) Hand washing
d) Face washing
Answer: Hand washing
Explanation: Hand washing is widely recognized as the single most effective way to prevent the spread of infections. It breaks the chain of transmission by removing pathogens from the hands before they can be transferred to other people, surfaces, or one's own mucous membranes.
17. Florence Nightingale's focus in the Crimean War was—
a) Writing care plans
b) Mental health
c) Clean environment
d) Upgrading education
Answer: Clean environment
Explanation: Florence Nightingale pioneered the concept that a clean environment (sanitation, fresh air, and hygiene) significantly reduces infection rates. This foundational principle led to modern sterilization and disinfection practices in hospitals.
18. Which of the following is considered as the most important aspect of hand washing?
a) Soap
b) Water
c) Friction
d) Time
Answer: Friction
Explanation: Friction is the most critical component of hand hygiene. The mechanical action of rubbing hands together (for at least 20 seconds) physically breaks down the protective membranes of microorganisms and dislodges dirt, oil, and transient pathogens from the skin so they can be rinsed away.
19. Sanitation barrier is the —
a) Protection of foods
b) Propaganda of flies
c) Segregation of faeces
d) Provision of safe water
Answer: Segregation of faeces
Explanation: In environmental disinfection and public health, the "primary barrier" to prevent the spread of waterborne and foodborne diseases is the segregation of faeces. By safely disposing of human waste, the chain of infection is broken at the source, preventing pathogens from contaminating water, hands, or soil.
20. Presence of pathogenic bacteria in the blood is known as —
a) Toxemia
b) Septicemia
c) Bacteremia
d) All of the above
Answer: Bacteremia
Explanation: While the terms are often used interchangeably in casual conversation, Bacteremia specifically refers to the simple presence of bacteria in the bloodstream. If those bacteria begin to multiply and cause a systemic inflammatory response, the condition progresses to Septicemia (Sepsis).
