Ch 20 Antimicrobial Drugs

__________ discovered penicillin and the first clinical trials in 1940 demonstrated its effectiveness as a chemotherapeutic agent.

Alexander Fleming

__________are substances that inhibit other microorganisms and are produced by bacteria and fungi.

Antibiotics

Bacterial infections are easier to treat using chemotherapy than are other types of infections caused by other types of microorganisms. Why?

Bacteria are prokaryotic.

Which of the following mechanisms is antifungal?

Inhibit ergosterol synthesis

Which antimicrobial works by inhibiting the synthesis of mycolic acid?

Isoniazid

Which of the following statements about antibiotics is true?

Most of our antibiotics are produced by Streptomyces, a genus of filamentous soil bacteria.

Which of the following antibiotics inhibits protein synthesis?

Streptomycin

Which of the following is NOT a reason for the selective toxicity of sulfa drugs?

Sulfa drugs cause production of antimetabolites.

You are reviewing the following results of a disk- diffusion antibiotic susceptibility test on an isolate of Staphylococcus aureus: Antibiotic A: ZI (zone of inhibition) = 0 millimeters Antibiotic B: ZI = 23 millimeters > Antibiotic C: ZI = 16 millimeters Antibiotic D: ZI = 19 millimeters Which antibiotic is bactericidal?

The correct answer cannot be determined from the information provided. Antimicrobial drugs are either bactericidal (they kill microbes directly) or bacteriostatic (they prevent microbes from growing).

Which of the following statements is true about superinfections?

They may be caused by antibiotic-resistant bacteria.

A drug that inhibits peptidoglycan synthesis is __________.

antibacterial

A chemical that kills gram-positive bacteria and gram-negative bacteria would best be described as __________.

broad spectrum

A drug that binds with sterols would injure __________.

eukaryotic plasma membranes

An antimicrobial drug that inhibits peptidoglycan synthesis is most likely to be effective against __________.

gram-positive bacteria

A disadvantage of using broad-spectrum antibiotics for treating bacterial infections is the potential for __________.

superinfection

Clindamycin binds to the 50S ribosomal subunit to inhibit translocation. This antibiotic stops __________.

translation in prokaryotes