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

Question 1

Which of the following antifungals works by inhibiting ergosterol synthesis?

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

Answer 1

C

Question 2

The antimicrobials called quinolones act by

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

Answer 2

E

Question 3

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

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

Answer 3

E

Question 4

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

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

Question 5

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

Question 6

Most broad- spectrum antibiotics act by

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

Question 7

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

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

Question 8

Which of the following statements is true of selective toxicity?

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

Question 9

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

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

Question 10

Antimicrobial sugar analogs are effective for

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

Question 11

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

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

Question 12

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

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

Question 13

Pentamidine is an example of an antimicrobial that

A) inhibits cell wall synthesis.
B) binds to DNA.
C) disrupts cytoplasmic membranes.
D) inhibits metabolic pathways.
E) binds to ribosomes.

Question 14

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

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

Question 15

The therapeutic range of an antimicrobial is the

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

Question 16

The tetracyclines interfere with

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

Question 17

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

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

Question 18

The mechanism of action of the antibiotic vancomycin is

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

Question 19

How does resistance to drugs spread in bacterial populations?

A) Horizontal gene transfer between bacteria spreads R (resistance) plasmids.
B) Exposure to drugs causes mutations in bacterial genes.
C) The formation of biofilms protects bacteria from the effects of drugs.
D) Exposure to drugs alters gene expression in bacteria.
E) Both horizontal gene transfer and the growth of biofilms spread drug resistance.

Question 20

The first synthetic antimicrobial widely available for treatment of infections

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

Question 21

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

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

Question 22

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

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

Question 23

Antimicrobials that block protein synthesis by binding to the mRNA are

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

Question 24

Which of the following type of antimicrobial agent has the narrowest spectrum of action?

A) erythromycins
B) antivirals
C) azoles
D) sulphonamides
E) Both azoles and erythromycins have equally narrow spectrums of action.

Question 25

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

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

Question 26

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

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

Question 27

Which of the following pathways is specifically inhibited by sulfonamides?

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

Question 28

The E- test determines which of the following?

A) MIC (minimum inhibitory concentration)
B) MBC (minimum bactericidal concentration)
C) susceptibility
D) both MBC (minimum bactericidal concentration) and MIC (minimum inhibitory concentration)
E) both susceptibility and MIC (minimum inhibitory concentration)

Question 29

Which of the following antibiotics disrupts cytoplasmic membrane function?

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

Question 30

Ribavirin is an antiviral that interferes with

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

Question 31

In the compound lamivudine an - SH group replaces an - OH group found in cytosine. When used as a medication it will

A) interfere with nucleic acid synthesis.
B) disrupt membrane structure.
C) disrupt lipid membrane structure.
D) interfere with protein synthesis.
E) interfere with cell wall synthesis.

Question 32

Drug- resistant populations of microbes arise when

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

Question 33

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

A) preventing the formation of fi- lactamases.
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 cross- linkage of NAM subunits.

Question 34

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

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

Question 35

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

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

Question 36

The mechanism of action of erythromycin is

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

Question 37

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

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

Question 38

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

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

Question 39

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) sulfonamides
E) tetracyclines

Question 40

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

Question 41

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

Question 42

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

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

Question 43

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

Question 44

Drugs that slow down bacterial growth would be (competitive/synergistic/antagonistic) to penicillin.

Question 45

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

Question 46

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

Question 47

Second- generation drugs are semisynthetic drugs developed to combat (immunity/resistance) against an existing drug.

Question 48

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

Question 49

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

Question 50

The antimicrobial polymyxin

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

Question 51

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

Question 52

Some medications for influenza are (attachment/binding/microbial) antagonists that block the ability of the virus to enter cells.

Question 53

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

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

Question 54

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

Question 55

The abbreviation (MIC/MID/MD) 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 56

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

Question 57

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

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

Question 58

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) resistance.

Question 59

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

Question 60

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

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

Question 61

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 62

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

Question 63

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

Question 64

Examine the diffusion susceptibility plate results shown in this figure. 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.

Question 65

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

Question 66

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

Question 67

Nucleic acid analog drugs act by inhibiting ribosome function.

Question 68

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

Question 69

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

Question 70

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

Question 71

R- plasmids are extrachromosomal DNAs that contain genes for antimicrobial resistance.

Question 72

Explain the concept of selective toxicity.

Question 73

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

Question 74

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

Question 75

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