Chapter 14 Multiple Choice

Match the antimicrobial agent to its mode of action. artemisinin atovaquone imidazole pentamidine quinoline affects DNA and RNA, and, therefore, protein production inhibits ergosterol synthesis interferes with heme detoxification produces reactive oxygen species competes with coenzyme Q for electrons

artemisinin - produces reactive oxygen species atovaquone - competes with coenzyme Q for electrons imidazole - inhibits ergosterol synthesis pentamidine - affects DNA and RNA, and, therefore, protein production quinoline - interferes with heme detoxification

You have discovered a new antibiotic. It is lipophilic and detergent-like. On the basis of this information, its target is most likely which of the following? the bacterial ribosome peptidoglycan the plasma membrane nucleic acid synthesis machinery

the plasma membrane

Which clinical situation would be appropriate for treatment with a narrow-spectrum antimicrobial drug? treatment of strep throat caused by culture identified Streptococcus pyogenes treatment of a polymicrobic mixed infection in the intestine empiric therapy of pneumonia while waiting for culture results prophylaxis against infection after a surgical procedure

treatment of strep throat caused by culture identified Streptococcus pyogenes

Reverse transcriptase inhibitors, such as AZT, can be used to target which virus? herpes rabies HIV influenza

HIV

Which of the following commonly results from most antibiotic classes that bind to the 50S ribosomal subunit? Peptide bond formation is inhibited. The proofreading mechanism of the ribosome is inhibited. tRNAs charged with an amino acid cannot enter the ribosome. Proteins made from this ribosome insert into the plasma membrane.

Peptide bond formation is inhibited.

A macrobroth dilution assay to determine the MIC of amoxicillin on E. coli is shown below. What is the MIC? 0.05 µg/mL 5 µg/mL 1 µg/mL 0.01 µg/mL

0.05 µg/mL

Using the Etest shown below, determine the approximate MIC of this antibiotic against the bacterium plated. 256 µg/mL 8 µg/mL 0.05 µg/mL 0.12 µg/mL

0.05 µg/mL

Which of the following drug classes specifically inhibits neuronal transmission in helminthes? Benzimidazoles Amantadines Imidazoles Avermectins

Avermectins

How does bacitracin work? Bacitracin binds to penicillin-binding proteins, thus inhibiting the transpeptidation reaction during cell wall synthesis. Bacitracin binds to penicillin-binding proteins, thus inhibiting the transglycosylation reaction during cell wall synthesis. Bacitracin blocks the movement of peptidoglycan subunits from the cytoplasm to the exterior of the cell. Bacitracin inserts into the plasma membrane, causing cell lysis

Bacitracin blocks the movement of peptidoglycan subunits from the cytoplasm to the exterior of the cell.

The bacterium known for causing pseudomembranous colitis, a potentially deadly superinfection, is ________.

Clostridium difficile/ C. difficile

The method that can determine the MICs of multiple antimicrobial drugs against a microbial strain using a single agar plate is called the ________.

E test

The ________ is the lowest concentration of a drug that kills at least 99.9% of the starting inoculum.

MBC/ minimum bactericidal concentration

The ________ is the lowest concentration of a drug that inhibits visible growth in culture.

MIC/ minimal inhibitory concentration

Which is the target of the antimicrobial drug known as rifampin? DNA gyrase RNA polymerase DNA polymerase helicase

RNA polymerase

Antimicrobial agents may be the metabolites of microorganisms or synthetically made. True False

T

Chloramphenicol should be used sparingly because it also inhibits the large subunit of mitochondrial ribosomes. True False

T

Continued use of quinolones can lead to hallucinations, cardiac complications, and, potentially, anemia. True False

T

Echinocandins, known as "penicillin for fungi," target β(1→3) glucan synthesis in fungal cell walls. True False

T

If antibiotic treatment is needed for immunocompromised individuals who develop infections, the medications should be bactericidal rather than bacteriostatic. True False

T

Isoniazid is an antimetabolite that can be used to treat mycobacterial infections. True False

T

The group of soil bacteria known for their ability to produce a wide variety of antimicrobials is called the ______________.

actinomycetes or actinobacteria

Antiviral drugs, like Tamiflu and Relenza, that are effective against the influenza virus by preventing viral escape from host cells are called ________.

antivirals

Which of the following is an antimalarial drug that is thought to increase reactive oxygen species (ROS) levels in target cells? amphotericin b pleconaril artemisinin praziquantel

artemisinin

Which of the following is a nucleoside analog commonly used as a reverse transcriptase inhibitor in the treatment of HIV? acyclovir adenine-arabinoside ribavirin azidothymidine

azidothymidine

Match the antimicrobial agent to its mode of action. bacitracin diarylquinoline isonicotinic acid hydrazide polymyxin rifampin inhibits nucleic acid synthesis acts as an antimetabolite disrupts cell membranes inhibits cell wall synthesis inhibits ATP synthase

bacitracin - inhibits cell wall synthesis diarylquinoline - inhibits ATP synthase isonicotinic acid hydrazide - acts as an antimetabolite polymyxin - disrupts cell membranes rifampin - inhibits nucleic acid synthesis

Life-threatening diseases caused by bacterial pathogens should be treated with which of the following? neither bacteriostatic nor bactericidal agents both bacteriostatic and bactericidal agents bacteriostatic agents only bactericidal agents only

bactericidal agents only

At the hospital, the first antimicrobial drug given, especially when the pathogen is not yet known, is often a ________-spectrum drug

broad

Match the antimicrobial agent to its mode of action. chloramphenicol fluoroquinolone penicillin tetracycline trimethoprim inhibits cell wall synthesis inhibits the 30S ribosomal subunit acts as an antimetabolite inhibits nucleic acid synthesis inhibits the 50S ribosomal subunit

chloramphenicol- inhibits the 50S ribosomal subunit fluoroquinolone - inhibits nucleic acid synthesis penicillin - inhibits cell wall synthesis tetracycline - inhibits the 30S ribosomal subunit trimethoprim - acts as an antimetabolite

Which of the following is not an appropriate target for antifungal drugs? cholesterol β(1→3) glucan chitin ergosterol

cholesterol

In the Kirby-Bauer disk diffusion test, the _______ of the zone of inhibition is measured and used for interpretation. diameter circumference microbial population depth

circumference

Sulfa drugs (sulfonamides) inhibit which metabolic pathway? Embden-Meyerhof pathway Entner-Doudoroff pathway dihydrofolic acid synthesis pathway pentose-phosphate pathway

dihydrofolic acid synthesis pathway

Which of the following resistance mechanisms is commonly effective against a wide range of antimicrobials in multiple classes? target mimicry efflux pump target overproduction target modification

efflux pump

Which of the following resistance mechanisms is the most nonspecific to a particular class of antimicrobials? drug modification efflux pump target mimicry target modification

efflux pump

Most antifungal agents target ________, which is found in the fungal cell membrane.

ergosterol

Which of the following antimicrobials inhibits the activity of DNA gyrase? polymyxin B fluoroquinolones rifampin clindamycin

fluoroquinolones

Which of the following routes of administration would be appropriate and convenient for home administration of an antimicrobial to treat a systemic infection? parenteral topical oral intravenous

oral

Which of the following terms refers to the ability of an antimicrobial drug to harm the target microbe without harming the host? therapeutic level spectrum of activity selective toxicity mode of action

selective toxicity

Ampicillin and amoxicillin are ________ penicillins.

semisynthetic

Which of the following does not bind to the 50S ribosomal subunit? tetracyclines macrolides lincosamides chloramphenicol

tetracyclines

Penicillin inhibits the ________ reaction of cell wall synthesis.

transpeptidation or cross-linking

How does penicillin work? Penicillin inserts into the plasma membrane, causing cell lysis. Penicillin blocks the movement of peptidoglycan subunits from the cytoplasm to the exterior of the cell. Penicillin binds to penicillin-binding proteins, thus inhibiting the transpeptidation reaction during cell wall synthesis. Penicillin binds to penicillin-binding proteins, thus inhibiting the transglycosylation reaction during cell wall synthesis.

Penicillin binds to penicillin-binding proteins, thus inhibiting the transpeptidation reaction during cell wall synthesis.

The Etest combines both the Kirby-Bauer disk diffusion assay and the minimum inhibitory concentration dilution assay to determine the effectiveness of an antimicrobial compound. True False

T

The rate of discovery of antimicrobial drugs has decreased significantly in recent decades. True False

T

If drug A produces a larger zone of inhibition than drug B on the Kirby-Bauer disk diffusion test, drug A shouldalways be prescribed. True False

F

Individuals cannot have MRSA as part of their normal flora or microbiota. True False

F

Narrow-spectrum antimicrobials are commonly used for prophylaxis following surgery. True False

F

Tamiflu is a hemagglutinin inhibitor commonly used against influenza virus. True False

F

The Kirby-Bauer disk diffusion assay can distinguish between bacteriostatic and bactericidal agents. True False

F

β-lactamases can degrade vancomycin. True False

F

The aminoglycosides directly target which structure of the bacterial cell? 30S ribosomal subunit cell wall plasma membrane 50S ribosomal subunit

30S ribosomal subunit

The macrolides target which feature of the bacterial cell? 50S ribosomal subunit cell wall plasma membrane 30S ribosomal subunit

50S ribosomal subunit

Which describes the difference between a secondary infection and a superinfection? A secondary infection is a type of superinfection that develops when antibiotics are not given. A superinfection is a type of secondary infection that can develop when antibiotics kill much of the patient's normal flora. A superinfection is a type of secondary infection that develops when antibiotics taken to treat a particular pathogen do not completely kill all of that original pathogen. A secondary infection is a type of superinfection that develops when the pathogen mutates in response to the antimicrobial agent.

A superinfection is a type of secondary infection that can develop when antibiotics kill much of the patient's normal flora.

Which is the target of the class of antimicrobial drugs known as fluoroquinolones? RNA polymerase DNA gyrase DNA polymerase helicase

DNA gyrase

Both vancomycin and penicillin target the bacterial cell wall and have the same mode of action. True False

F

Which of the following resistance mechanisms describes the function of β-lactamase with the enzymatic hydrolysis of the β-lactam bond within the β-lactam ring of the drug molecule? drug inactivation target mimicry target overproduction efflux pump

drug inactivation

Which of the following is not a type of β-lactam antimicrobial? cephalosporins penicillins monobactams glycopeptides

glycopeptides

Benzimidazoles and avermectins are used to treat which type of infection? helminth protozoan bacterial fungal

helminth

Which of the following techniques can not be used to determine the minimum inhibitory concentration of an antimicrobial drug against a particular microbe? Kirby-Bauer disk diffusion test Etest macrobroth dilution test Etest

macrobroth dilution test

Artemisinin and quinolines are antimicrobials used against what disease?

malaria

The penicillins act on which type of bacteria? mostly gram-negative bacteria and some gram-positive bacteria gram-positive bacteria only mostly gram-positive bacteria and some gram-negative bacteria gram-negative bacteria only

mostly gram-positive bacteria and some gram-negative bacteria

Selective toxicity antimicrobials are easier to develop against bacteria because they are ________ cells, whereas human cells are eukaryotic.

prokaryotic

Metronidazole and pentamidine are used to treat which type of infection? fungal protozoan helminth bacterial

protozoan

Staphylococcus aureus, including MRSA strains, may commonly be carried as a normal member of the ________ microbiota in some people.

resident

A scientist discovers that a soil bacterium he has been studying produces an antimicrobial that kills gram negative bacteria. She isolates and purifies the antimicrobial compound, then chemically converts a chemical side chain to a hydroxyl group. When she tests the antimicrobial properties of this new version, she finds that this antimicrobial drug can now also kill gram-positive bacteria. The new antimicrobial drug with broad-spectrum activity is considered to be which of the following? resistant synthetic semisynthetic natural

semisynthetic

Which of the following combinations would most likely contribute to the development of a superinfection? short-term use of narrow-spectrum antimicrobials long-term use of narrow-spectrum antimicrobials long-term use of broad-spectrum antimicrobials short-term use of broad-spectrum antimicrobials

short-term use of broad-spectrum antimicrobials

The microbial environment that has been investigated most thoroughly for the production of antimicrobial compounds is ________?

soil

Which of the following environments has yielded compounds with the most antimicrobial activity? volcanoes air water soil

soil

Which of the following antimicrobial drugs is synthetic? neomycin sulfanilamide penicillin actinomycin

sulfanilamide

What mechanism of resistance is used by both MRSA and VRSA? efflux pump blocked/reduced penetration inactivation of enzyme target modification

target modification