Microbiology Ch. 20

Mebendazole is used to treat cestode infections. It interferes with microtubule formation; therefore, it would NOT affect

• Bacteria.

• Helminths.

• Human cells.

• Protozoa.

• Fungi.

Which of the following statements about drugs that competitively inhibit DNA polymerase or RNA polymerase is false?

• They interfere with protein synthesis.

• They can affect host cell DNA.

• They are used against viral infections.

• They cause mutations.

• They are too dangerous to use.

Which of the following does NOT affect eukaryotic cells?

• Antifungal drugs

• Semisynthetic penicillins

• Nucleotide analogs

• Antihelminthic drugs

• Antiprotozoan drugs

Which compound would be the most useful to treat candidiasis?

• Thymine

• Flucytosine

• Penicillin

• Uracil

• Guanine

Which of the following does NOT constitute an advantage of using two antibiotics together?

• Two are always twice as effective as one.

• It lessens the toxicity of individual drugs.

• It can prevent drug resistance.

• It allows treatment to be provided prior to diagnosis.

• All of these are advantages.

In the presence of penicillin, a cell dies because

• It lacks a cell membrane.

• It undergoes osmotic lysis.

• It plasmolyzes.

• It lacks a cell wall.

• Its contents leak out.

Which of the following antibiotics does NOT interfere with cell wall synthesis?

• Macrolides

• Semisynthetic penicillins

• Cephalosporins

• Vancomycin

• Natural penicillins

Which of these antimicrobial agents has the fewest side effects?

• Penicillin

• Streptomycin

• Chloramphenicol

• Tetracycline

• Erythromycin

Use of antibiotics in animal feed leads to antibiotic-resistant bacteria because

• Bacteria from other animals replace those killed by the antibiotics.

• The few surviving bacteria that are affected by the antibiotics develop immunity to the antibiotics, which they pass on to their progeny.

• The antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.

• The antibiotics cause new mutations to occur in the surviving bacteria, which results in resistance to antibiotics.

• The antibiotics persist in soil and water.

More than half of our antibiotics are

• Produced by fungi.

• Produced by eukaryotic organisms.

• Synthesized in laboratories.

• Produced by Fleming.

• Produced by bacteria.