Question 1

Which of the following is an example of a physical method of microbial control commonly used in hospitals to sterilize surgical instruments?

Accepted Answer

Autoclaving at $121^\circ$C and 15 psi for 15 minutes

Question 2

A laboratory is working with the Ebola virus, which requires the highest level of containment. Which biosafety level is appropriate for this work, and what is a key feature of this level?

Accepted Answer

BSL-4; requires full-body, air-supplied, positive pressure suits

Question 3

Which of the following is NOT a desirable characteristic of an ideal chemical disinfectant for use in a hospital setting?

Accepted Answer

It is inactivated by organic matter

Question 4

A food processing plant needs to reduce microbial contamination on packaging materials without using heat. Which physical method is most appropriate?

Accepted Answer

Ionizing radiation (gamma rays)

Question 5

Which of the following pairs correctly matches a chemical control agent with its primary target and typical application?

Accepted Answer

Glutaraldehyde; proteins; sterilizing medical equipment

Question 6

A researcher is working with Staphylococcus aureus, a moderate-risk organism. Which biosafety level is required, and what is a typical precaution at this level?

Accepted Answer

BSL-2; use of gloves and lab coats

Question 7

Which of the following factors should be considered when selecting a microbial control agent for disinfecting a hospital room after a patient with Clostridioides difficile infection?

Accepted Answer

The agent must be sporicidal

Question 8

Which method is classified as a chemical control and is commonly used to disinfect drinking water?

Accepted Answer

Chlorination

Question 9

A pharmaceutical company needs to sterilize heat-sensitive solutions. Which method is most appropriate?

Accepted Answer

Membrane filtration

Question 10

Which of the following best describes the difference between disinfection and sterilization?

Accepted Answer

Sterilization destroys all forms of microbial life, while disinfection eliminates most pathogens but not necessarily spores

Question 11

A hospital is considering two disinfectants. Disinfectant A is effective in the presence of organic matter, while Disinfectant B is not. Which is a more desirable characteristic for a hospital disinfectant, and why?

Accepted Answer

Disinfectant A, because it remains effective even when blood or tissue is present

Question 12

Which of the following scenarios best illustrates the use of a biosafety level 3 (BSL-3) laboratory?

Accepted Answer

Research on Mycobacterium tuberculosis with controlled access and negative air pressure

Question 13

Which of the following is a limitation of using ultraviolet (UV) radiation as a physical control method?

Accepted Answer

UV radiation does not penetrate surfaces or opaque materials

Question 14

A nurse uses an alcohol-based hand sanitizer before entering a patient's room. Which statement best describes the action of alcohol as a microbial control agent?

Accepted Answer

Alcohol denatures proteins and disrupts cell membranes

Question 15

Which of the following is an example of a scenario requiring BSL-1 precautions?

Accepted Answer

Culturing non-pathogenic E. coli K-12 in a teaching laboratory

Question 16

A hospital is evaluating a new disinfectant. Which equation would be most useful for determining the rate of microbial death during exposure to the disinfectant?

Accepted Answer

The decimal reduction time equation: $D = \frac{t}{\log_{10}(N_0/N)}$

Question 17

Which of the following best explains why filtration is preferred over heat sterilization for some pharmaceutical products?

Accepted Answer

Filtration does not denature heat-sensitive compounds

Question 18

A hospital is considering using phenol as a disinfectant. Which of the following is a major disadvantage of phenol?

Accepted Answer

It is toxic and can cause skin irritation

Question 19

Which of the following is a correct match between a biosafety level and an example organism?

Accepted Answer

BSL-2: Salmonella enterica

Question 20

A hospital needs to sterilize mattresses and heat-sensitive plastics. Which method is most appropriate and why?

Accepted Answer

Ethylene oxide gas, because it penetrates porous materials and is effective at low temperatures

Guided Study: Controlling Microbial Growth in the Environment

Study Guide - Practice Questions

Study Guide - Flashcards