Deck 19: Antibiotics and Antimicrobial Drugs

Question 1

Which of the following is not a drug used for protozoan and helminth infections?

A)Metronidazole
B)Flucytosine
C)Chloroquine
D)Piperazine
E)Melarsoprol

Answer 1

Flucytosine

Question 2

Cephalosporins are more effective than the penicillins against Gram-negative bacteria because they

A)Are unable to penetrate the outer membrane through the porin molecules
B)Lack a beta-lactam ring
C)Have a longer half-life in vivo
D)Contain Cilastatin, which prevents destruction of the antibiotic by the kidneys
E)Are resistant to ?-lactamase enzyme activity

Answer 2

Are resistant to ?-lactamase enzyme activity

Question 3

Penicillin resistance in bacteria is conferred by the production of

A)Lysozyme
B)Transglycosylase
C)β-lactamase
D)N-acetylglucosamine
E)Penicillin-binding proteins

Answer 3

β-lactamase

Question 4

Clavulanic acid is an

A)Penicillin-binding protein modifier
B)β-lactamase inhibitor
C)Efflux pump inhibitor
D)Immune response stimulator

Question 5

Which of the following is not a drug used for viral infections?

A)Zanamivir
B)Lamivudine (3TC)
C)Ritonavir
D)Flucytosine
E)Ganciclovir

Question 6

Disruption of DNA synthesis occurs if _____ is targeted by antibiotics.

A)Bacterial RNA polymerase
B)N-acetylglucosamine
C)Bacterial topoisomerase
D)The A site of the bacterial ribosome

Question 7

The efficacy of penicillin is highest during the _____ phase of the bacterial life cycle.

A)Static
B)Active growth
C)Stationary
D)Death

Question 8

An antimicrobial compound that is activated enzymatically after its introduction into the body is a

A)Prodrug
B)Antibiotic
C)Probiotic
D)Competitive inhibitor

Question 9

Which of the following antibiotics prevents ?-lactamase cleavage by binding to it?

A)Cephalosporins
B)Carbapenems
C)Monobactams
D)Glycopeptide antibiotics
E)Penicillins

Question 10

All of the following target the 50S ribosomal subunit except

A)Chloramphenicol
B)Azithromycin
C)Streptomycin
D)Erythromycin

Question 11

A pair of antibiotics used to treat vancomycin-resistant enterococcal infections is marketed under the name

A)Synercid
B)Augmentin
C)Timentin
D)Primaxin
E)Unasyn

Question 12

All of the following target the bacterial ribosomal except

A)Chloramphenicol
B)Erythromycin
C)Spectinomycin
D)Streptomycin
E)Teicoplanin

Question 13

Augmentin combines amoxicillin with _____ to overcome enzymatic resistance to the antibiotic by the microbe.

A)β-lactamase
B)Clavulanic acid
C)Transpeptidase
D)Sulbactam
E)Cilastatin

Question 14

Which of the following is a mismatched pair?

A)Acyclovir (nucleoside analog): herpes simplex virus
B)Zanamivir (neuraminidase inhibitor): cytomegalovirus
C)Azidothymidine (AZT; nucleoside analog): HIV
D)Ribavirin (nucleoside analog): respiratory syncytial virus
E)Amantadine (viral un-coating inhibitor): influenza A

Question 15

Which of the following antibiotics is mismatched with its mode of action?

A)Vancomycin: inhibition of cell wall synthesis in Gram-negative bacteria
B)Aminoglycosides: binding to 30S ribosomal subunit and blocking of protein synthesis
C)Isoniazid: inhibition of mycolic acid synthesis
D)Polymyxin B: disruption of plasma membrane
E)Polypeptide antibiotics: inhibition of peptidoglycan polymerization

Question 16

People began to think that infectious disease was a thing of the past because of antibiotics.

Question 17

Which of the following is the drug combination of choice when treating tuberculosis?

A)Vancomycin, imipenem, aztreonam
B)Methicillin, teicoplanin, isoniazid
C)Polymyxin B, ethambutol, erythromycin
D)Isoniazid, ethambutol, rifampin
E)Tetracycline, rifamycin, ciprofloxacin

Question 18

Which of the following is not a drug used for fungal infections?

A)Azoles
B)Foscarnet
C)Pentamidine
D)Amphotericin B
E)Flucytosine

Question 19

Bacteria that have evolved the ability to produce ?-lactamase have become resistant to penicillin because all forms of penicillin contain this ring structure.

Question 20

Ampicillin is referred to as a semi-synthetic form of penicillin because it blocks the synthesis of half the cell wall components.

Question 21

The most appealing target for antibiotics is the bacterial cell wall,because it is on the outside of the cell.

Question 22

Explain how sulfa drugs exert their antimicrobial effects.Why is this lethal to the bacterium and how are these drugs selectively toxic?

Question 23

Why is it advantageous for bacteria such as Streptomyces species to synthesize antibiotics? Explain three ways in which antibiotic-producing microorganisms protect themselves from the effects of these compounds.

Question 24

Making semi-synthetic antibiotics in the laboratory by altering the side chains of naturally occurring antibiotics is an important approach for generating new antibiotics.Why is a search for new antibiotics needed? Provide examples of new desirable properties conferred on antibiotics through these types of chemical modification.

Question 25

Discuss selective toxicity as it relates to antimicrobials.

Question 26

Compare the mechanisms of the anti-trypanosomal drugs eflomithine and melasoprol.

Question 27

Explain why are antibiotics that are protein synthesis inhibitors are excellent choices for therapy in the context of toxicity? Why might large doses of protein synthesis inhibitor antibiotics show toxic effects in eukaryotic cells even though they meet the criterion for selective toxicity?

Question 28

The treatment of malaria has changed since quinine was first used in the 1600s.What has changed and why?