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

Question 1

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.

Answer 1

C

Question 2

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 2

B

Question 3

A drug is structurally similar to PABA and inhibits folic acid synthesis.It is most likely a(n)

A) nucleic acid analog.
B) penicillin.
C) tetracycline.
D) azole.
E) sulfonamide.

Answer 3

E

Question 4

Which of the following antibiotics disrupts cytoplasmic membrane function in fungi?

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

Question 5

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 6

Who proposed the concept of chemotherapy,that compounds might selectively kill pathogens without harming people?

A) Gerhard Domagk
B) Alexander Fleming
C) Paul Ehrlich
D) Selman Waksman
E) Joseph Lister

Question 7

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 8

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 9

Which of the following antifungals works by binding to ergosterol in membranes?

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

Question 10

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

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

Question 11

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 12

Bacillus licheniformis secretes a compound that inhibits the growth of other Gram-positive bacteria.This is an example of a(n)

A) analog.
B) antibiotic.
C) chemotherapeutic.
D) porin.
E) toxin.

Question 13

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 14

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 15

A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication.This product would be a(n)

A) antibiotic.
B) analog.
C) semisynthetic antimicrobial.
D) synthetic antimicrobial.
E) probiotic.

Question 16

Figure represents a Petri plate.The gray area is where bacteria A is growing,the black area is where bacteria B is growing.The white area is a zone where neither organism is growing.What is the best interpretation of what is observed on the plate?

A) Bacteria B is producing an antibiotic that inhibits the growth of bacteria A.
B) Bacteria A produces a compound that inhibits the growth of bacteria B.
C) Bacteria A grows faster than bacteria B.
D) Bacterial colony B has depleted the nutrients in the area around the colony.
E) No conclusion can be made from this information.

Question 17

Amoxicillin is very effective for treating infections with Gram-positive bacteria but rarely causes side effects in humans.This is an example of

A) selective toxicity.
B) narrow spectrum of action.
C) a broad-spectrum antimicrobial.
D) antibiotic resistance.
E) altruism.

Question 18

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 19

What does "narrow spectrum antimicrobial" mean?

A) The antimicrobial is effective for a very short time.
B) The antimicrobial is effective against a few microbes.
C) The antimicrobial can only be administered to a small segment of the population.
D) The antimicrobial is activated by a specific wavelength in the visible spectrum.
E) The antimicrobial is effective on all bacteria but not eukaryotes.

Question 20

The first antimicrobial widely available for treatment of bacterial infections was a synthetic compound which

A) was an antimetabolic analog.
B) was a nucleotide analog.
C) was an attachment antagonist.
D) disrupted cytoplasmic membranes.
E) interfered with bacterial cell wall synthesis.

Question 21

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 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 difficult 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

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 24

The antimicrobials called quinolones act by

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

Question 25

How does resistance to drugs spread in bacterial populations?

A) Exposure to drugs causes mutations in bacterial genes.
B) Horizontal gene transfer between bacteria spreads R (resistance) plasmids.
C) Genetic recombination during sexual reproduction.
D) Exposure to drugs induces immunity.
E) Exposure to drugs alters gene expression in bacteria.

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

Antimicrobials known as "attachment antagonists" are particularly useful for preventing

A) bacterial protein synthesis.
B) cell membrane synthesis.
C) virus infection.
D) nucleic acid synthesis.
E) biofilm formation.

Question 28

The broth dilution test can provide information for determining

A) the molecular target of an antibiotic.
B) the MIC (minimum inhibitor concentration).
C) the rate of diffusion of an antibiotic.
D) the MBC (minimum bactericidal concentration), with an additional step.
E) both the MIC and the MBC (with an additional step).

Question 29

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 30

A "zone of inhibition" is associated with which of the following tests used to determine the efficacy of antibiotics?

A) Etest
B) diffusion susceptibility test
C) broth dilution test
D) both the Etest and diffusion susceptibility test
E) both the broth dilution and the MBC tests

Question 31

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 32

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 33

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

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

Question 34

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 35

Pentamidine is an example of an antimicrobial

A) used to treat bacterial infections.
B) effective against helminths.
C) used to treat viral infections.
D) effective against eukaryotes, especially protozoa.
E) used to treat both bacterial and fungal infections.

Question 36

Which of the following steps in the folic acid synthesis pathway 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 37

Some bacteria are resistant to antimicrobials due to the activity of ________,which removes many of them.

A) plasmids
B) porins
C) efflux pumps
D) lipopolysaccharides
E) ribosomes

Question 38

Who discovered the first antimicrobial widely available to the general public?

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

Question 39

The therapeutic range of an antimicrobial is the

A) ratio of the dose a patient can tolerate to the effective dose.
B) range of microorganisms the antimicrobial effects.
C) range of concentrations at which the antimicrobial is both effective and non-toxic.
D) ratio of the concentration of antimicrobial in the blood to the oral dose.
E) length of time the medication persists in the body after a single dose.

Question 40

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 41

Nucleotide or nucleoside (acids/analogs/antisense)are antimicrobial agents that mimic the chemical structure of DNA building blocks.

Question 42

Biofilms contribute to the spread of resistance to antimicrobials.

Question 43

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

Question 44

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

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

Question 45

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 46

Medications administered intravenously can provide much higher effective concentrations than other delivery methods.

Question 47

Any drug that acts against a disease is called a(n)(analog/antibiotic/chemotherapeutic)agent.

Question 48

Selective (action/toxicity/treatment)means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated.

Question 49

Antisense nucleic acids interfere with protein synthesis.

Question 50

Nucleic acid analog drugs have no effect on human cell replication function.

Question 51

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 52

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

Question 53

Secondary infections that result from the killing of some of the normal microbiota are called (antagonism/superinfections/resistance).

Question 54

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

Question 55

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

Question 56

Drug-resistant populations of microbes arise when

A) exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells.
B) exposure to drugs causes mutations that produce resistance.
C) resistant cells become numerous in a population due to their greater vigor.
D) the patient becomes immune to the drug.
E) synergy between medications occurs.

Question 57

A microbe resistant to a variety of different antimicrobials is said to have (cross/drug/multiple)resistance.

Question 58

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

Question 59

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

Question 60

AZT and Valaciclovir are antiviral nucleoside analogs that interfere with

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

Question 61

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

Question 62

The abbreviation (MBC/MIC/MID)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 63

A (bacteriocidial/bacteriostatic/minimum)concentration of a drug is one at which microbes survive but are not able to grow and reproduce.

Question 64

Some bacteria develop resistance to groups of drugs because the drugs are all structurally similar to each other; this is a phenomenon known as (cross/multiple/synergistic)resistance.

Question 65

External infections can be treated by (intramuscular/surface/topical)administration,in which a drug is applied directly to the site of infection.

Question 66

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

Question 67

Semisynthetic drugs developed to combat resistance are often called (analog/second generation/synergist)drugs.

Question 68

Antiviral medications frequently block unique (proteins/enzymes/molecules)to prevent production of a new virus.

Question 69

Examine the diffusion susceptibility plate results shown in Figure 10.2.Propose an explanation for the appearance of the zone around the S/10 disk,and discuss the implications for therapeutic use of this antibiotic for the pathogen tested.

Question 70

The ratio of a medication's dose that can be tolerated to its effective dose is the therapeutic (MIC/index/range)of the medication.

Question 71

Competition between beneficial microbes and potential pathogens is called microbial (antagonisms/synergy/toxicity).

Question 72

Drugs known as beta-lactams interfere with bacterial (DNA/folic acid/cell wall)synthesis.

Question 73

A newly discovered prokaryote produces a compound with promising antimicrobial effects.Devise a set of tests to determine whether the antimicrobial is broad or narrow spectrum and bactericidal or bacteriostatic.

Question 74

Explain the concept of selective toxicity.

Question 75

Medications which block viral entry into cells include (adhesin/analog/attachment)antagonists.