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

Question 1

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

Answer 1

C

Question 2

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.

Answer 2

C

Question 3

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.

Answer 3

A

Question 4

Beta-lactam antibiotics such as penicillins, 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 5

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 6

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 7

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.

Question 8

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 9

The drug metronidazole is effective on both bacteria and some protozoa. It can therefore be described as a ________ drug.

A) narrow spectrum
B) broad spectrum
C) full spectrum
D) general spectrum
E) specific spectrum

Question 10

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

A) Bacterial cells become more susceptible to osmotic pressure.
B) Bacteria cannot attach to their hosts.
C) Cytoplasmic membrane proteins lose their function.
D) The sterols in the bacterial cell wall become nonfunctional.
E) No change in bacterial cell activity.

Question 11

Some bacteria are resistant to erythromycin as a result of mutation of their ribosomal RNA. What type of resistance does this represent?

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

Question 12

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 13

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 14

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 15

The topical drug ________ inhibits protein synthesis in Gram positive bacteria by preventing loading of isoleucine onto tRNA.

A) Amphotericin B
B) Bacitracin
C) Ciprofloxacin
D) Mupirocin
E) Tetracycline

Question 16

Figure 10.1 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

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 is a primary advantage of semisynthetic drugs?

A) They are less stable and consequently have fewer side effects.
B) They work faster.
C) They are more effective than the unmodified natural antibiotics.
D) They must be administered intravenously.
E) They are not readily absorbed.

Question 19

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 20

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

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

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

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) Streptococcus
E) both Candida albicans and Clostridium difficile

Question 23

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 24

Which of the following statements is true of selective toxicity?

A) Selective toxicity takes advantage of structural similarities 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 differences in metabolic rates of the host and pathogen.
D) Selective toxicity damages only pathogenic bacteria and not beneficial bacteria.
E) Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen.

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

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 27

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 28

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

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

Question 29

Which of the following tests does NOT provide information on the lowest concentration of drug effective on a pathogen?

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

Question 30

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 31

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 32

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 33

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 34

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 35

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 36

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 37

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

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

Question 38

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 39

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 40

The antifungals known as polyenes interact with ________, a lipid unique to fungus membranes.

A) cholesterol
B) ergosterol
C) mycolic acid
D) phospholipid
E) glycolic acid

Question 41

There are relatively few antifungal medications available compared to antibacterial drugs.

Question 42

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

Question 43

Biofilms contribute to the spread of resistance to antimicrobials.

Question 44

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

Question 45

Antisense nucleic acids interfere with protein synthesis.

Question 46

Paul Erhlich discovered the first antibiotic.

Question 47

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

Question 48

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

Question 49

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

Question 50

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

Question 51

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

Question 52

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 53

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

Question 54

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

Question 55

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 56

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 57

The mechanism of action of ciprofloxacin 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 58

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

Question 59

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 60

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

Question 61

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

Question 62

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

Question 63

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 64

Explain the concept of selective toxicity.

Question 65

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

Question 66

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 67

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

Question 68

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

Question 69

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 70

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

Question 71

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

Question 72

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 73

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 74

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

Question 75

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