11. Controlling Microbial Growth

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

Which of the following statements is relevant in explaining why sulfonamides are effective?

a. Sulfonamides attach to sterol lipids in the pathogen, disrupt the membranes, and lyse the cells.

b. Sulfonamides prevent the incorporation of amino acids into polypeptide chains.

c. Humans and microbes use PABA differently in their metabolism.

d. Sulfonamides inhibit DNA replication in both pathogens and human cells.

Support or refute the following statement: Antimicrobial agents make cells become resistant.

A man has been given a broad-spectrum antibiotic for his stomach ulcer. What unintended consequences could arise from this therapy?

Compare and contrast the actions of polyenes, azoles, allylamines, and polymyxin.

What is the difference in drug action of synergists contrasted with that of antagonists?

PABA is __________ .

a. a substrate used in the production of penicillin

b. a type of β-lactamase

c. molecularly similar to cephalosporins

d. used to synthesize folic acid

Which of the following statements is false concerning antiviral drugs?

a. Macrolide drugs block attachment sites on the host cell wall and prevent viruses from entering.

b. Drugs that neutralize the acidity of phagolysosomes prevent viral uncoating.

c. Nucleotide analogs can be used to stop microbial replication.

d. Drugs containing protease inhibitors retard viral growth by blocking the production of essential viral proteins.

What specific test for antimicrobial efficacy is shown? What does this test measure? Draw an oval to predict the size and shape of the zone of inhibition if the drug concentration on the strip were increased twofold.

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