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

Question 1

Most broad-spectrum antibiotics act by

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

Answer 1

A

Question 2

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

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

Answer 2

B

Question 3

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

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

Answer 3

A

Question 4

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

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

Question 5

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

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

Question 6

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

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

Question 7

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

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

Question 8

Medications which should NOT be prescribed for a pregnant woman include

A) sulfonamides.
B) tetracyclines.
C) penicillins.
D) aminoglycosides.
E) sulfonamides and tetracyclines.

Question 9

Broad-spectrum synthetic antimicrobials were discovered by

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

Question 10

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) toxin.
E) porin.

Question 11

A medication that inhibits synthesis of ergosterol would be effective in treating

A) viral disease.
B) protozoal infections.
C) Mycobacterial disease.
D) bacterial infections.
E) fungal infections.

Question 12

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

Question 13

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 lipid membrane structure.
C) disrupt membrane structure.
D) interfere with cell wall synthesis.
E) interfere with protein synthesis.

Question 14

The first synthetic antimicrobial widely available for treatment of infections

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

Question 15

A new antibacterial medication prevents the assembly of ribosomes on mRNA. The new medication would be

A) a type of macrolide.
B) an antisense RNA.
C) a type of oxazolidinone.
D) either an antisense RNA or a type of macrolide.
E) either an antisense RNA or a type of oxazolidinone.

Question 16

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

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

Question 17

A medication which specifically targets cell walls that contain arabinogalactan -mycolic acid is

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

Question 18

The CDC issued alerts about a bacterial strain known as NDM1 (New Delhi metalo-lactamase 1). What type of antibiotic resistance is indicated by the name?

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

Question 19

Which of the following antibiotics disrupts cytoplasmic membrane function?

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

Question 20

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 grows faster than bacteria B.
B) Bacteria B is producing an antibiotic that inhibits the growth of bacteria A.
C) Bacteria A produces a compound that inhibits the growth of 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 21

Antimicrobial sugar analogs are effective for

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

Question 22

Which of the following is measured in the broth dilution test?

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

Question 23

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) mitochondria
D) ribosomes
E) porins

Question 24

Inhibiters of DNA synthesis specifically effective on prokaryotes are

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

Question 25

The mechanism of action of the antibiotic vancomycin is

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

Question 26

Bacterial DNA replication requires the enzyme gyrase, but eukaryotic replication does not. Ciprofloxacin (ʺCiproʺ) inhibits gyrase activity. This is an example of

A) selective toxicity.
B) antimicrobial resistance.
C) synergism.
D) use of an analog.
E) an antimetabolite.

Question 27

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) length of time the medication persists in the body after a single dose.
E) ratio of the concentration of antimicrobial in the blood to the oral dose.

Question 28

The E-test determines which of the following?

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

Question 29

Several antiviral medications used to treat HIV interfere with

A) protein synthesis.
B) folic acid synthesis.
C) cell wall synthesis.
D) nucleic acid synthesis.
E) assembly of membranes.

Question 30

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

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

Question 31

How does resistance to drugs spread in bacterial populations?

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

Question 32

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

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

Question 33

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

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

Question 34

Which of the following pathways is specifically inhibited by trimethoprim?

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

Question 35

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

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

Question 36

Synthetic antimicrobials that block protein synthesis by binding to the mRNA are

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

Question 37

A sulfonamide and trimethoprim may be administered in combination to

A) inhibit multiple metabolic pathways.
B) reduce development of antibiotic resistance.
C) treat infections with microbes that require folic acid.
D) provide broad-spectrum action.
E) reduce relative toxicity.

Question 38

Pentamidine is an example of an antimicrobial that

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

Question 39

The β-lactams are narrow spectrum antibacterials because

A) they are analogs for a compound metabolized only by Gram -negative bacteria.
B) they are analogs for a unique cell membrane lipid.
C) they block a synthetic step unique to the Gram-positive bacteria.
D) the outer membrane prevents their entry into cells.
E) the thick peptidoglycan walls prevent their entry into cells.

Question 40

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

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

Question 41

Nucleic acid analog drugs act by inhibiting ribosome function.

Question 42

Ribavirin is an antiviral that interferes with

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

Question 43

The majority of broad spectrum antibacterial medications inhibit (DNA/protein/RNA) synthesis.

Question 44

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

Question 45

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

Question 46

A compound that slows the activity of efflux pumps, when administered with an antibiotic which requires high concentration to be effective, the combination is highly effective for treating bacterial infections. This is an example of synergy.

Question 47

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

Question 48

The antimicrobial polymyxin is primarily effective for treating superficial infections with

A) viruses.
B) fungi.
C) any bacteria.
D) Gram-negative bacteria.
E) Staphylococcus bacteria.

Question 49

A side effect known as ʺblack hairy tongueʺ may result from antifungal therapy.

Question 50

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

Question 51

The mechanism of action of erythromycin is

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

Question 52

While not the first person to discover antibiotics (Domagk/Fleming/Waksman) discovered the sources of many useful antibiotics.

Question 53

Paul Ehrlich coined the term antibiotics for the ʺmagic bulletʺ antimicrobials he pursued.)

Question 54

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) the patient becomes immune to the drug.
D) exposure to drugs causes mutations that produce resistance.
E) exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells.

Question 55

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

Question 56

Antiviral medications can best be described as

A) antibiotics produced by bacteria.
B) synthetic antimicrobials.
C) extremely narrow spectrum synthetic antimicrobials.
D) extremely narrow spectrum antimicrobials.
E) broad spectrum antimicrobials.

Question 57

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

Question 58

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

Question 59

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

Question 60

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

Question 61

A recent publication from the CDC contained the following statement:
ʺCarbapenem-resistant Enterobacteriaceae (CRE) are pathogens that have emerged in the United States as a serious public health threat. They are resistant to almost all drugs, difficult to treat, and are associated with high death rates (up to 40% in some studies).ʺ
The bacteria referred to as CRE are Gram-negative bacteria that are frequently part of the normal microbiota. Discuss some of the reasons for the high level of concern about CREs.

Question 62

Examine the diffusion susceptibility plate results shown in this figure. 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 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

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

Question 65

The abbreviation (MIC/MID/MBC) stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen.

Question 66

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

Question 67

Macrolides inhibit protein synthesis by blocking (catalysis/binding/movement) of the ribosome.

Question 68

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

Question 69

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

Question 70

The action of some antivirals prevent (attachment/synthesis/uncoating), an event shortly after entry of the virus into the cell.

Question 71

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

Question 72

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

Question 73

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

Question 74

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 75

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