Ch.9 Antimicrobial Chemotherapy Test Questions & Answers

Prescott's Microbiology, 11e (Willey)

Chapter 9 Antimicrobial Chemotherapy

1) Who is usually credited with the discovery of penicillin?

A) Fleming

B) Florey and Chain

C) Duchesne

D) Ehrlich

2) Whose discovery of streptomycin stimulated an intense search for other antibiotics?

A) Waksman

B) Ehrlich

C) Fleming

D) Pasteur

3) The use of the arsenic compound Salvarsan as a treatment for syphilis is credited to ________.

A) Fleming

B) Ehrlich

C) Waksman

D) Chain

4) Chemotherapeutic agents that are natural products of microorganisms are most specifically referred to as ________.

A) antimicrobial agents

B) synthetic drugs

C) antibiotics

D) semisynthetic drugs

5) Who is generally credited with the discovery of sulfanilamide as a chemotherapeutic agent?

A) Gerhard Domagk

B) Ernest Duchesne

C) Ernst Chain

D) Robert Koch

6) ________ ________ are activities of a chemotherapeutic agent that damage the host either by inhibiting the same process in the host as in the target cell or by damaging other processes.

7) The minimum lethal concentration (MLC) is the lowest concentration of drug from which organisms fail to recover when removed from the drug.

8) Agents that are static and, therefore, do not kill infecting microorganisms are not useful as chemotherapeutic agents.

9) A drug that disrupts a microbial function not found in animal cells usually has a higher therapeutic index.

10) The drug level required for the clinical treatment of a particular infection is called the ________.

A) therapeutic dose

B) toxic dose

C) therapeutic index

D) minimal inhibitory concentration

11) Which of the following inhibits protein synthesis?

A) Dapsone

B) Erythromycin

C) Penicillin

D) Isoniazid

12) Which of the following is likely to have the most toxic side effects to humans?

A) Inhibitors of cell wall synthesis

B) Inhibitors of protein synthesis

C) Disrupters of cell membrane structure

D) Inhibitors of DNA synthesis

13) Isoniazid is a narrow-spectrum antibiotic that ________.

A) is not useful as a chemotherapeutic agent

B) is one of the few drugs effective against Mycobacterium tuberculosis

C) is one of the few drugs effective against systemic fungal infections

D) None of the choices are correct.

14) Consider an antibacterial drug. In which of the following cases would the action of the drug be considered primarily bacteriostatic?

A) The minimal lethal concentration (MLC) is equal to the minimal inhibitory concentration (MIC).

B) The MLC is lower than the MIC.

C) The MLC is 2–4 times higher than the MIC.

D) The MLC is 10–20 times higher than the MIC.

15) Chemotherapeutic agents that are chemically modified natural products of microorganisms are most specifically referred to as ________.

A) antimicrobial agents

B) synthetic drugs

C) antibiotics

D) semisynthetic drugs

16) Chemotherapeutic agents that are artificially produced are most specifically referred to as ________.

A) antimicrobial agents

B) synthetic drugs

C) antibiotics

D) semisynthetic drugs

17) The ratio of toxic dose to therapeutic dose is called the ________.

A) toxicity index

B) phenol coefficient

C) therapeutic index

D) susceptibility quotient

18) The minimal lethal concentration (MLC) is the ________.

A) lowest concentration of a drug that prevents growth of a particular pathogen

B) highest concentration of a drug that prevents growth of a particular pathogen

C) lowest concentration of a drug that kills a particular pathogen

D) highest concentration of a drug that kills a particular pathogen

19) The lowest concentration of an antibiotic that prevents growth is the ________.

A) minimal inhibitory concentration (MIC)

B) minimal lethal concentration (MLC)

C) 50% inhibitory dose

D) All of the choices are correct.

20) Which of the following is a desirable general characteristic of antimicrobial drugs?

A) Selective toxicity

B) Broad-spectrum of activity

C) Bactericidal rather than bacteriostatic

D) All of the choices are correct.

21) When a chemotherapeutic agent is effective against many different pathogens including both Gram-positive and Gram-negative bacteria, it is said to be a ________ antibiotic.

22) When comparing two drugs in a disk diffusion assay for drug susceptibility, the drug that produces the larger zone of inhibition is always more effective than the one that produces the smaller zone.

23) Which of the following affects the size of the clear zone in a disk diffusion test of antimicrobial susceptibility?

A) The initial concentration of the drug

B) The solubility of the drug

C) The diffusion rate of the drug

D) All of the choices are correct.

24) The E test is ________.

A) a rapid serological test used to detect the presence of eastern equine encephalitis virus in cerebrospinal fluid

B) a quantitative antibiotic sensitivity test that utilizes plastic strips impregnated with an antibiotic of interest

C) used to quantify levels of IgE antibody in serum samples

D) used to measure esculine levels in pasteurized milk

25) In the broth dilution test, the highest concentration of the antibiotic resulting in no growth after 16 to 20 hours of incubation is the MIC.

26) Which of the following is NOT true about Kirby-Bauer disk diffusion method?

A) Bacteria used to swab plate a test plate should be at least a week old.  

B) The designation of resistance or sensitivity to a drug is determined by comparing the size of the zone of inhibition to a standard table.

C) As the minimum inhibitory concentration value increases, the sensitivity of the organism to the drug decreases.

D) The diameters of the zones of inhibition are measured to the nearest millimeter.

27) Which of the following does not inhibit protein synthesis?

A) Tetracycline

B) Streptomycin

C) Erythromycin

D) Penicillin

E) All of the choices inhibit protein synthesis.

28) The most selective antibacterial agents are those that interfere with bacterial cell wall synthesis. This is because ________.

A) bacterial cell walls have a unique structure not found in eukaryotic host cells

B) bacterial cell wall synthesis is easily inhibited whereas eukaryotic cell wall synthesis is more resistant to the actions of the drugs

C) eukaryotic cells do not take up the drugs

D) eukaryotic cells inactivate the drugs before they can do any damage

29) In addition to inhibiting the transpeptidation reaction in cell wall synthesis, penicillins may also destroy bacteria by ________.

A) inhibiting DNA replication

B) stimulating proteins to form holes in the plasma membrane

C) inhibiting protein synthesis

D) None of the choices are correct.

30) Aminoglycoside antibiotics ________.

A) inhibit cell wall synthesis

B) inhibit folic acid biosynthesis

C) bind to the 30S ribosomal subunit

D) bind to bacterial DNA polymerase

31) Sulfonamides and other drugs that inhibit folic acid synthesis have a high therapeutic index because ________.

A) humans do not use folic acid

B) humans do not synthesize folic acid but obtain it in their diets

C) humans synthesize folic acid by a process that is not sensitive to sulfonamides

D) None of the choices are correct.

32) Antibiotics that are given by injection are said to have a/an ________ route of administration.

A) oral

B) venal

C) parenteral

D) topical

33) Sulfonamides inhibit the production of folic acid and, therefore, inhibit the synthesis of ________.

A) purines and pyrimidines

B) ribose

C) aromatic amino acids

D) peptidoglycan

34) Which of the following is (are) true about cephalosporins?

A) They, like penicillin, inhibit bacterial cell wall synthesis.

B) There are four generations of cephalosporins.

C) They can be given to patients with penicillin allergies.

D) All of the choices are correct.

35) Bacitracin ________.

A) inhibits DNA replication

B) inhibits peptidoglycan synthesis

C) interferes with protein synthesis

D) interferes with plasma membrane function

36) Vancomycin ________.

A) inhibits the transglycosylase reaction in peptidoglycan biosynthesis

B) interferes with the action of the lipid carrier that transports peptidoglycan precursors across the plasma membrane

C) inhibits the transpeptidation reaction in peptidoglycan biosynthesis

D) blocks the addition of the pentapeptide chain during peptidoglycan biosynthesis

37) Which of the following is a useful mechanism of action for an antibacterial drug?

A) Inhibition of cell wall synthesis

B) Inhibition of protein synthesis

C) Interference with RNA and DNA synthesis

D) All of the choices are correct.

38) Which of the following antibiotics specifically inhibits DNA synthesis?

A) Gentamycin

B) Polymyxin B

C) Quinolones

D) Tetracycline

39) Protein synthesis inhibitors have a low therapeutic index because they usually cannot discriminate between prokaryotic and eukaryotic ribosomes.

40) Ampicillin, like penicillin, must be administered by injection because it is rapidly degraded in the stomach and cannot, therefore, be given orally.

41) A(n) ________ is a drug that blocks the function of a metabolic pathway.

42) Which of the following is normally treated by antifungal creams and solutions?

A) Systemic mycoses

B) Superficial mycoses

C) Subcutaneous mycoses

D) Intramuscular mycoses

43) The treatment for pneumonia caused by Pneumocystis jiroveci in AIDS patients is ________.

A) Streptomycin

B) Miconazole

C) combination of trimethoprim and sulfisoxazole

D) Amantadine

44) Treatment of fungal infections is more difficult than treatment of bacterial infections because the greater metabolic similarity between the fungi and their hosts limits the ability of a drug to have a selective toxicity.

45) Amphotericin B from Streptomyces spp. binds to the sterols in fungal membranes, disrupting membrane permeability and causing leakage of cell constituents.

46) A neuraminidase inhibitor called ________ is sometimes used in the treatment of people infected with influenza viruses.

47) Which of the following is sometimes useful against viral infections?

A) Trimethoprim

B) Streptomycin

C) Azidothymidine

D) Rifampin

48) Which of the following is the major reason why it has been difficult to treat viral infections with chemotherapeutic agents?

A) Viral metabolism resembles that of their hosts so there is no selective point of attack.

B) Viruses use the metabolic machinery of their hosts, which limits many of the potential points of attack.

C) Viruses have no metabolism and therefore offer no selective point of attack.

D) Actually, viruses are not difficult to treat with chemotherapeutic agents.

49) All of the following are reverse transcriptase inhibitors used to treat HIV infection EXCEPT ________.

A) azidothymidine

B) zalcitabine

C) lamivudine

D) didanosine

E) acyclovir

50) The antiviral drugs currently approved for use in HIV disease include ________.

A) nucleoside reverse transcriptase inhibitors

B) nonnucleoside reverse transcriptase inhibitors

C) protease inhibitors

D) fusion inhibitors

E) All of the choices are correct.

51) Drugs used to treat malaria include ________.

A) chloroquine

B) qualaquin

C) metronidazole

D) chloroquine and qualaquin

52) Metronidazole is used to treat Entamoeba infections.

53) The antimicrobial action of artemisinin is not well understood but this chemical appears to ________.

A) swell the Plasmodium falciparum food vacuoles

B) form reactive oxygen intermediates inside Plasmodium-infected red blood cells

C) inhibit heme polymerase, an enzyme that converts toxic heme into nontoxic hemazoin

D) raise the internal pH, clump the plasmodial pigment, and intercalate into plasmodial DNA

54) Most of the drugs used to treat protozoan infection have insignificant side effects; because protozoa are eukaryotes, the potential for drug action on host cells and tissues is less than it is when targeting bacteria.

55) Bacteria in biofilms or abscesses may be replicating very slowly and are therefore resistant to chemotherapy because many agents affect pathogens only if they are actively growing and dividing.

56) The chemotherapeutic agent must reach levels in the body that are ________ the pathogen's MIC value if it is going to be effective.

A) greater than

B) equal to

C) less than

57) The concentration of an antimicrobial drug that is reached in the body will depend on ________.

A) the amount of drug administered

B) the route of administration and speed of uptake

C) the rate at which the drug is cleared or eliminated from the body

D) All of the choices are correct.

58) Penicillin G is frequently injected but not normally given orally because it is rapidly degraded in the stomach.

59) Genes for drug resistance may be present ________.

A) on the chromosome

B) on plasmids

C) on mitochondrial DNA

D) both on the chromosome and on plasmids

60) One way in which organisms may exhibit resistance to a drug is the ability to pump the drug out of the cell immediately after it has entered.

61) The effects of most antimicrobial drugs are greater if the microorganisms are actively growing.

62) One way that the development of drug resistance in viruses has been reduced has been by the use of a cocktail of several drugs at high doses.

63) Development of drug resistance is encouraged by ________.

A) use of a high enough concentration of the drug to destroy any spontaneous resistant mutants that might arise

B) use of two drugs simultaneously with the hope that each will prevent the emergence of resistance to the other

C) avoidance of indiscriminate use of drugs

D) using drugs appropriate for the infectious agent being treated

E) widespread use of broad-spectrum drugs

64) Which of the following is (are) used by microorganisms to become resistant to a particular drug?

A) Enzymatic inactivation of the drug

B) Exclusion of the drug from the cell

C) An alternate metabolic pathway that bypasses the drug-sensitive step

D) All of the choices are correct.

65) In order for successful antibiotic therapy, the in vivo level of the antibiotic must be greater than or equal to the MIC.

66) An antimicrobial drug that inhibits the growth of bacteria without affecting the growth or function of cells in the human host is described as being ___________ ________.

67) The aminoglycosides and tetracyclines specifically target the ________ interfering with ________.

A) 30S ribosomal subunit; protein synthesis

B) cell membrane enzymes; transpeptidation step of peptidoglycan synthesis

C) topoisomerases; DNA replication

D) tRNAs; protein synthesis

68) Most antiprotozoal drugs have few side effects since there are numerous cellular targets found in protozoa but not found in host cells that can be targeted with antiprotozoal drugs.

69) The major reason why there are fewer antiprotozoal drugs than antibacterial drugs is because ________.

A) antiprotozoal drugs are not needed in the United States

B) antiprotozoal drugs cost much more than antibacterial drugs to develop

C) it is much more difficult to develop selectively toxic antiprotozoal drugs since protozoan cells are eukaryotic

D) antiprotozoal drugs are only effective when injected

70) Genes for antibiotic resistance can be found in antibiotic-producing bacteria as well as in non-antibiotic-producing bacteria. 

71) All of the following are appropriate strategies for overcoming drug resistance in bacteria except ________.

A) decreasing the use of antibiotics in agriculture

B) patient compliance with dosage instructions when taking antibiotics

C) heightened infection control in health care facilities

D) prudent use of antibiotics when treating viral infections

72) One strategy to overcome antibiotic resistance is to use the same antibiotics in animal husbandry as those that are prescribed for humans, since the potential for resistant bacteria to evolve would be limited to only a small number of drug classes.

73) Select the response that describes a broad-spectrum drug.

A) A drug that is effective against E. coli (Gram-negative) and Staphylococcus aureus (Gram-positive)

B) A drug that is effective against Staphylococcus and Streptococcus (Gram-positive) but not Klebsiella (Gram-negative)

C) A drug that is effective against Gram-positive organisms

D) A drug that is effective against Gram-negative organisms

74) Fluoroquinolones are known to damage tendons and nerves in patients taking the drug.  Side effects from quinolones are unavoidable because ________.

A) they inhibit DNA synthesis, and bacteria and eukaryotes carry out very similar mechanisms for DNA replication

B) their mechanism of action is to disrupt cytoskeletal fibers in bacteria, which correlates to connective tissue in humans

C) they disrupt folic acid synthesis, and both bacteria and humans require folic acid for growth

D) they inhibit protein synthesis in bacterial cells, which simultaneously disrupts protein synthesis in the host, preventing the production of cartilage

75) Compared to antibiotics, there are fewer antiviral agents available because ________.

A) before drugs were developed that could directly target virus-specific enzymes, it was thought that any antiviral agent would have to target host cell processes, ultimately damaging cells and tissues

B) they are much more costly to produce due to the small size of viruses compared to bacteria

C) antibiotics are produced by other bacteria, whereas all antivirals have to be synthesized in a laboratory

D) viruses are not as deadly as bacteria so research dollars have been spent developing antibacterial drugs

76) Medicinal chemists that synthesize drugs to kill pathogenic protozoans aim to target a novel mechanism to promote selective toxicity.  The reason there are fewer antiprotozoal drugs compared to antibacterials is that ________.

A) there are few novel molecular mechanisms in protozoa compared to human hosts since both are eukaryotes, so toxicity is an issue

B) targeting novel mechanisms in protozoans is far more costly than it is for bacterial cells

C) protozoans are not pathogenic compared to bacteria so developing drugs is not cost-effective

D) most antiprotozoal drugs also kill bacteria so they are not given their own category