Textbook of Diagnostic Microbiology 4th Edition Test Bank
Mahon: Textbook of Diagnostic Microbiology, 4th Edition
Chapter 04: Control of
... [Show More] Microorganisms
Test Bank
MULTIPLE CHOICE
1. The chemical or physical method that destroys all forms of life is called:
a. Sterilization
b. Disinfection
c. Bacteriostatic
d. Bactericidal
ANS: A
Sterilization is the destruction of all forms of life, including bacterial spores. Disinfection is a process that eliminates a defined scope of microorganisms, including, in some cases, spores. Bacteriostatic inhibits the growth of microorganisms. Bactericidal kills bacteria.
REF: page 62 OBJ: Level 1 – Recall
2. Organisms that are the most resistant to heat, chemicals, and radiation are:
a. Parasites
b. Prions
c. Bacteria
d. Viruses
ANS: B
Prions are naked pieces of protein, so they are harder to kill than any other organism. Viruses usually contain a nucleic acid, and all the mentioned forms of killing can effectively disrupt their nucleic acid. Bacteria and parasites are complete organisms that are killed by disinfection and sterilization, even in the spore and cyst stages.
REF: page 63 OBJ: Level 1 – Recall
3. After using the phone, the laboratory tech sprayed the receiver with a chemical spray. This process will kill a defined scope of microorganisms. What is this process called?
a. Sterilization
b. Bacteriostatic
c. Disinfection
d. Bactericidal
ANS: C
Sterilization kills all organisms and spores at a site. Bacteriostatic and bactericidal are adjectives that describe the particular action of chemical agents: to inhibit bacterial growth or kill bacteria. Disinfection kills a defined scope of microorganisms.
REF: page 62 OBJ: Level 2 – Interpretation
4. Before performing a phlebotomy, the phlebotomist will clean the area on a patient’s arm with a substance before inserting the needle. This substance is called a(n):
a. Disinfectant
b. Sterilizer
c. Antiseptic
d. Bactericidal
ANS: C
A disinfectant is a chemical agent used to kill microorganisms on an inanimate object. To sterilize is to kill all life; skin will still have organisms growing after wiping. Bactericidal is the process of killing bacteria. An antiseptic is a substance applied to the skin for the purpose of eliminating or reducing the number of bacteria present.
REF: page 62 OBJ: Level 2 – Interpretation
5. All the following factors play a significant role in the selection and implementation of the appropriate method of disinfection EXCEPT:
a. Temperature
b. Contact time
c. Biofilms
d. Humidity
ANS: D
Temperature, contact time, and biofilms all play a role in selection and implementation of the appropriate method of disinfection. Humidity is not important when attempting to disinfect or kill organisms.
REF: pages 62-63 OBJ: Level 1 – Recall
6. When eliminating organisms from inanimate objects, higher numbers of organisms require longer exposure times because:
a. All disinfecting agents are not alike and some require shorter times.
b. The chemical composition of the disinfecting agent varies.
c. Disinfecting agents containing carbon tetrachloride require longer times to act.
d. It takes longer to eliminate 99% of microorganisms.
ANS: D
When there are higher numbers of microorganisms, it takes longer to kill 99% of microorganisms present. Although disinfectants are different, it still takes longer to kill more organisms. The chemical composition of a disinfecting agent may affect the time required to kill microorganisms, but microbial load is a determining factor. [Show Less]