Deck 10: Controlling Microbial Growth in the Body: Antimicrobial Drugs

Question 1

Which of the following antibiotics disrupts cytoplasmic membrane function?

A) streptomycin
B) erythromycin
C) tetracycline
D) penicillin
E) amphotericin B

Answer 1

E

Question 2

Another term for the Kirby-Bauer test is the

A) minimum inhibitory concentration test.
B) E test.
C) diffusion susceptibility test.
D) minimum bactericidal concentration test.
E) broth dilution test.

Answer 2

C

Question 3

β-lactamase production is an example of which of the following types of resistance?

A) alteration of the target of the drug
B) inactivation of the drug
C) change in the permeability of the drug
D) overproduction of an enzyme in a key metabolic pathway
E) removal of the drug via a pump

Answer 3

B

Question 4

Which of the following statements about the zone of inhibition is FALSE?

A) It is measured as a diameter.
B) The larger the zone, the more resistant the organism is.
C) It is a clearing zone with no growth.
D) It is a result of diffusion of the drug out of the paper disk.
E) It is measured after incubation.

Question 5

The most limited group of antimicrobial agents is the __________ drugs.

A) antibacterial
B) antifungal
C) anthelmintic
D) antiviral
E) antiprotozoan

Question 6

A large percentage of antibiotics and semisynthetic drugs are produced by members of the genus

A) Cephalosporium.
B) Penicillium.
C) Bacillus.
D) Mycobacterium.
E) Streptomyces.

Question 7

Beta-lactam antibiotics have an effect on which of the following types of cells?

A) animal cells
B) bacterial cells
C) fungal cells
D) virus-infected cells
E) both animal and fungal cells

Question 8

Which of the following statements concerning development of antibiotic resistance is FALSE?

A) It is often mediated by R-plasmids.
B) Resistant cells are normally in the minority in a bacterial population.
C) Resistant cells grow more efficiently and quickly than susceptible cells.
D) New resistance genes can be gained through transformation, transduction, or conjugation.
E) Resistance can occur through mutation of existing bacterial genes.

Question 9

Most broad-spectrum antibiotics act by

A) inhibiting the synthesis of the cell wall.
B) inhibiting protein synthesis.
C) inhibiting nucleic acid synthesis.
D) inhibiting metabolic pathways.
E) disrupting the cytoplasmic membrane.

Question 10

Sulfonamides

A) are antimetabolic drugs.
B) were the first widely used antimicrobial drugs.
C) indirectly inhibit the synthesis of nucleic acids.
D) are no longer widely used.
E) were the first widely used antimetabolic antimicrobial and indirectly inhibit nucleic acid synthesis.

Question 11

Which of the following is a primary advantage of semisynthetic drugs?

A) They are less stable and consequently have fewer side effects.
B) They work faster.
C) They have a broader spectrum of action.
D) They must be administered intravenously.
E) They are not readily absorbed, so they persist longer.

Question 12

An antimicrobial that inhibits cell wall synthesis will result in which of the following?

A) Cells become more susceptible to osmotic pressure.
B) Cells cannot attach to their hosts.
C) Ribosomes lose their function.
D) The sterols in the cell wall become nonfunctional.
E) The replication of cells, including cancer cells, slows down.

Question 13

Which of the following can result when antibiotic therapy disrupts the normal microbiota?

A) anaphylactic shock
B) black hairy tongue
C) pseudomembranous colitis
D) thrush
E) both pseudomembranous colitis and thrush

Question 14

Probiotics

A) involve microbial antagonism.
B) are an alternative to the use of chemotherapy.
C) involve the use of extracts from microorganisms.
D) is a term for resistance to antibiotics.
E) are an alternative to the use of chemotherapy involving microbial antagonism.

Question 15

Which scientist coined the term antibiotic?

A) Fleming
B) Domagk
C) Kirby
D) Ehrlich
E) Waksman

Question 16

Most drugs that inhibit the synthesis of the cell wall act by

A) preventing the cross-linkage of NAM subunits.
B) blocking the secretion of cell wall molecules from the cytoplasm.
C) preventing the formation of alanine-alanine bridges.
D) disrupting the formation of the mycolic acid layer of the cell wall.
E) preventing the formation of β-lactamases.

Question 17

Which of the following groups of drugs can become incorporated into the bones and teeth of a fetus?

A) beta-lactams
B) aminoglycosides
C) quinolones
D) tetracyclines
E) sulfonamides

Question 18

Which of the following antifungals works by inhibiting ergosterol synthesis?

A) fluconazole
B) turbinafine
C) amphotericin B
D) nystatin
E) both fluconazole and turbinafine

Question 19

Which of the following is NOT a target of drugs that inhibit protein synthesis?

A) the shape of the 30S ribosomal subunit
B) interference with alanine-alanine bridges
C) the enzymatic site of the 50S ribosomal subunit
D) movement of the ribosome from one codon to the next
E) the tRNA docking site

Question 20

Which of the following drugs specifically targets cell walls that contain arabinogalactan-mycolic acid?

A) vancomycin
B) penicillin
C) methicillin
D) isoniazid
E) bacitracin

Question 21

Which of the following interferes with cell wall synthesis by blocking alanine bridge formation?

A) beta-lactams
B) cycloserine
C) bacitracin
D) vancomycin
E) both cycloserine and vancomycin

Question 22

It is inappropriate to prescribe antibacterial agents to treat colds or flu because

A) the microbes involved can develop resistance rapidly.
B) these diseases are transmitted by endospores, which are hard to kill.
C) these diseases exhibit cross resistance.
D) these diseases are caused by viruses.
E) these diseases can act synergistically with each other.

Question 23

Which of the following is NOT a criterion by which all antimicrobial agents can be evaluated?

A) their spectrum of action
B) their efficacy
C) their activity against cell walls
D) their route of administration
E) their safety

Question 24

Which of the following statements is true of selective toxicity?

A) Selective toxicity takes advantage of structural differences between host and pathogen.
B) To be effective, an antimicrobial agent must be more toxic to the patient than the pathogen.
C) Selective toxicity takes advantage of metabolic differences between host and pathogen.
D) Antimicrobial agents must target structural differences between host and pathogen and be more toxic to the patient than the pathogen.
E) Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen.

Question 25

The antimicrobials called quinolones act by

A) disrupting cytoplasmic membranes.
B) inhibiting cell wall synthesis.
C) inhibiting nucleic acid synthesis.
D) inhibiting a metabolic pathway.
E) inhibiting protein synthesis.

Question 26

Infection of the __________ would be the hardest to treat with antimicrobial drugs.

A) heart
B) kidneys
C) liver
D) brain
E) colon

Question 27

Alterations in the structure of which of the following are an important aspect of Gram-negative bacterial resistance to antimicrobial drugs?

A) plasmids
B) porins
C) mitochondria
D) cytoplasmic membrane
E) ribosomes

Question 28

Who discovered the first widely available antibiotic?

A) Domagk
B) Ehrlich
C) Fleming
D) Waksman
E) Ehrlich and Waksman

Question 29

The mechanism of action of the antibiotic vancomycin is

A) inhibition of protein synthesis.
B) inhibition of cell wall synthesis.
C) inhibition of nucleic acid synthesis.
D) inhibition of a metabolic pathway.
E) disruption of cytoplasmic membranes.

Question 30

Which of the following is a measurement associated with the broth dilution test?

A) the zone of inhibition
B) lack of turbidity
C) cell lysis
D) lack of turbidity and zone of inhibition
E) presence of turbidity and cell lysis

Question 31

Antimicrobial sugar analogs are effective for

A) preventing bacterial protein synthesis.
B) preventing cell membrane synthesis.
C) preventing virus attachment.
D) preventing nucleic acid synthesis.
E) blocking a metabolic pathway.

Question 32

Trimethoprim is an example of antimicrobials that

A) disrupt cytoplasmic membranes.
B) inhibit cell wall synthesis.
C) inhibit nucleic acid synthesis.
D) inhibit metabolic pathways.
E) inhibit protein synthesis.

Question 33

The Etest determines which of the following?

A) susceptibility
B) MBC
C) MIC
D) both susceptibility and MIC
E) both MBC and MIC

Question 34

Which of the following drugs inhibits nucleic acid synthesis specifically in prokaryotes?

A) quinolones
B) actinomycin
C) rifampin
D) tetracycline
E) 5-fluorocytosine

Question 35

Disruption of the normal microbiota can result in infections caused by which of the following microbes?

A) Mycobacterium
B) Candida albicans
C) Clostridium difficile
D) both Mycobacterium and Clostridium difficile
E) Candida albicans, Mycobacterium, and Clostridium difficile

Question 36

The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a β-lactamase inhibitor, is known as

A) cross resistance.
B) antimetabolism.
C) synergism.
D) selective toxicity.
E) chemotherapy.

Question 37

Antimicrobials that block protein synthesis by binding to the mRNA are

A) aminoglycosides.
B) antisense nucleic acids.
C) macrolides.
D) beta-lactams.
E) nucleic acid analogs.

Question 38

Amphotericin B is an antifungal drug that

A) inhibits protein synthesis.
B) inhibits nucleic acid synthesis.
C) blocks a metabolic pathway.
D) disrupts cytoplasmic membranes.
E) inhibits cell wall synthesis.

Question 39

The tetracyclines interfere with

A) protein synthesis.
B) cell wall synthesis.
C) cell membrane component synthesis.
D) nucleic acid synthesis.
E) folic acid synthesis.

Question 40

Which of the following pathways is specifically inhibited by sulfonamides?

A) the conversion of tetrahydrofolic acid to PABA
B) the conversion of PABA to dihydrofolic acid
C) the conversion of dihydrofolic acid to tetrahydrofolic acid
D) the conversion of PABA to tetrahydrofolic acid
E) the conversion of dihydrofolic acid to PABA

Question 41

Brain and spinal cord infections are difficult to treat because most antimicrobial drugs cannot diffuse out of the blood into these organs.

Question 42

Nucleotide or nucleoside __________are antimicrobial agents that mimic the chemical structure of DNA building blocks.

Question 43

Ribavirin is an antiviral that interferes with

A) protein synthesis.
B) cell wall synthesis.
C) cell membrane component synthesis.
D) nucleic acid synthesis.
E) viral attachment.

Question 44

Paul Erhlich coined the term antibiotics for the "magic bullet" antimicrobials he pursued.

Question 45

Selective __________ means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated.

Question 46

Beta-lactam drugs act by inhibiting formation of the cytoplasmic membrane.

Question 47

Any drug that acts against a disease is called a(n) __________ agent.

Question 48

Methicillin is an example of the beta-lactam class of drugs that

A) disrupt cytoplasmic membranes.
B) inhibit cell wall synthesis.
C) inhibit nucleic acid synthesis.
D) inhibit metabolic pathways.
E) inhibit protein synthesis.

Question 49

Secondary infections that result from the killing of the normal microbiota are called __________.

Question 50

The antimicrobial polymyxin

A) inhibits protein synthesis.
B) inhibits nucleic acid synthesis.
C) blocks a metabolic pathway.
D) disrupts cytoplasmic membranes.
E) inhibits cell wall synthesis.

Question 51

The mechanism of action of sulfonamides is

A) inhibition of metabolic pathways.
B) inhibition of cell wall synthesis.
C) inhibition of nucleic acid synthesis.
D) disruption of cytoplasmic membranes.
E) inhibition of protein synthesis.

Question 52

The mechanism of action of erythromycin is

A) inhibition of protein synthesis.
B) inhibition of cell wall synthesis.
C) inhibition of nucleic acid synthesis.
D) inhibition of a metabolic pathway.
E) disruption of cytoplasmic membranes.

Question 53

The outer membrane of Gram-negative bacteria enables many antimicrobial drugs to enter the cell more easily.

Question 54

Antisense nucleic acids are designed to have no side effects against humans.

Question 55

Organs that are commonly affected by drug toxicity include the kidneys and the liver.

Question 56

Because all cells engage in protein synthesis, there are few antimicrobial drugs that selectively inhibit this process.

Question 57

A broad-spectrum __________ is effective against a wide variety of pathogens.

Question 58

If a subculture of an MIC test grows in an MBC test, the concentration of the drug was bactericidal.

Question 59

Some bacterial cells are resistant to a variety of antimicrobials because they actively pump the drugs out of the cell.

Question 60

Many antimicrobial drugs that affect the cytoplasmic membrane are used only externally because they can be toxic to humans.

Question 61

Explain the concept of selective toxicity.

Question 62

Second-generation drugs are semisynthetic drugs developed to combat __________ against an existing drug.

Question 63

Some bacteria develop resistance to groups of drugs because the drugs are all structurally similar to each other; this is a phenomenon known as __________ resistance.

Question 64

Drugs that slow down bacterial growth would be __________ to penicillin.

Question 65

R-plasmids are __________ pieces of DNA that promote horizontal transfer of genes among bacteria and contribute to the spread of antimicrobial resistance.

Question 66

External infections can be treated by __________ administration, in which a drug is applied directly to the site of infection.

Question 67

The abbreviation __________ stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen. (Be sure to use all capital letters.)

Question 68

Praziquantel alters the cytoplasmic membrane permeability of __________ worms.

Question 69

Competition between beneficial microbes and potential pathogens is called microbial __________.

Question 70

Discuss the cellular factors that might make a drug's spectrum of action narrow rather than broad.

Question 71

Explain why many antibiotics are effective only against cells that are actively growing and reproducing.

Question 72

A(n) __________ concentration of a drug is one at which microbes survive but are not able to grow and reproduce.

Question 73

Antiviral medications frequently block unique __________ to prevent production of new virus.

Question 74

Why can microbial resistance to antibiotics and other drugs be considered a primarily genetic phenomenon?

Question 75

Examine the diffusion susceptibility plate results shown in Figure 10.9. Propose an explanation for the appearance of the zone around the AM/10 disk, and discuss the implications for therapeutic use of this antibiotic for the pathogen tested.