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

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

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