11. Controlling Microbial Growth

Which of the following substances or processes kills microorganisms on laboratory surfaces?

a. Antiseptics

b. Disinfectants

c. Degermers

d. Pasteurization

The microbial death rate is used to measure the effectiveness of:

a. A detergent

b. An antiseptic

c. Sanitization techniques

d. All of the above

Which of the following statements is true concerning the selection of an antimicrobial agent?

a. An ideal antimicrobial agent is stable during storage

b. An ideal antimicrobial agent is fast acting

c. Ideal microbial agents do not exist

d. All of the above are correct

Describe three types of microbes that are extremely resistant to antimicrobial treatment, and explain why they are resistant.

Compare and contrast four tests that have been developed to measure the effectiveness of disinfectants.

Why is it necessary to use strong disinfectants in areas exposed to tuberculosis patients?

Cross resistance is __________ .

a. the deactivation of an antimicrobial agent by a bacterial enzyme

b. alteration of the resistant cells so that an antimicrobial agent cannot attach

c. the mutation of genes that affect the cytoplasmic membrane channels so that antimicrobial agents cannot cross into the cell’s interior

d. resistance to one antimicrobial agent because of its similarity to another antimicrobial agent

Multiple-drug-resistant microbes _____________________  .

a. are resistant to all antimicrobial agents

b. respond to new antimicrobials by developing resistance

c. frequently develop in hospitals

d. all of the above

Which of the following is most closely associated with a beta-lactam ring?

a. penicillin

b. vancomycin

c. bacitracin

d. isoniazid

Drugs that act against protein synthesis include ___________ .

a. beta-lactams

b. trimethoprim

c. polymyxin

d. aminoglycosides

Why are alcohols more effective in a 70% solution than in a 100% solution?

Contrast the structures and actions of soaps and quats.

Diffusion and dilution tests that expose pathogens to antimicrobials are designed to determine __________ .

a. the spectrum of action of a drug

b. which drug is most effective against a particular pathogen

c. the amount of a drug to use against a particular pathogen

d. both b and c

In a Kirby-Bauer susceptibility test, the presence of a zone of inhibition around disks containing antimicrobial agents indicates __________ .

a. that the microbe does not grow in the presence of the agents

b. that the microbe grows well in the presence of the agents

c. the smallest amount of the agent that will inhibit the growth of the microbe

d. the minimum amount of an agent that kills the microbe in question

The key to successful chemotherapy is __________ .

a. selective toxicity

b. a diffusion test

c. the minimum inhibitory concentration test

d. the spectrum of action