MCQ's: Antibiotics

Question 1

Which of these antibiotics are effective against anaerobic bacteria?

Imipenem, metronidazole, trimethoprim, aztreonam, vancomycin

Answer 1

Metronidazole - anaerobes and parasites

Imipenem - broad spectrum including some anaerobes

Question 2

Aztreonam covers which bacteria?

Answer 2

Aztreonam is a monobactam and covers a wide range of gram negative

Question 3

What are bacteriocidal antibiotics?

Answer 3

Penicillins
Cephalosporins 
Carbapenems
Aminoglycosides 
Quinolone 
Metronidazole 
Vancomycin

Question 4

Which antibiotics are bacteriastatic?

Answer 4

Sulphonamide

Tetracyclines

Question 5

What is the mechanism of benzylpenicillin?

Answer 5

Inhibits cell wall synthesis

Question 6

Mechanism of actions of cephalosporins?

Answer 6

Inhibit cell wall synthesis.

All beta-lactams rings binds to proteins and prevent peptidoglycan cross-linkage in the bacterial cell-wall thus weakening it.

Question 7

Gentamicin mechanism of action?

Answer 7

Arrests protein synthesis by binding to 30S ribosomal RNA subunit.

Question 8

How does ciprofloxacin work?

Answer 8

Inhibits DNA synthase

Question 9

Mechanism of action of Rifampicin?

Answer 9

Binds to the RNA subunit of DNA-dependant RNA polymerase, preventing bacterial protein synthesis

Question 10

Agents that cover MRSA?

Answer 10

Meropenem, Ciprofloxacin, Vancomycin, Clindamycin, Fusidic acid, Teicoplanin

Question 11

Which of these have gram negative cover?

Vanc, gentamicin, ciprofloxacin, aztreonam, metronidazole

Answer 11

Gentamicin, Ciprofloxacin, Aztreonam

Question 12

Mechanism of action of Amphotericin B?

Answer 12

Creates pores in the fungal cell membrane

Question 13

Which azole antifungals are well absorbed orally?

Answer 13

All azoles except Miconazole

Question 14

How do azole antifungals work?

Answer 14

By affecting fungal ergosterol synthesis

Question 15

True or false:

dose adjustment is needed for ketoconazole in patients with renal failure.

Answer 15

False.

Ketoconazole is metabolised in the liver and inactive metabolites are excreted in the bile. No dose adjustment needed in renal failure.

Question 16

Which antibiotic cause ototoxicity?

Answer 16

Vancomycin and Gentamicin

Question 17

Which antibiotic causes red discolouration of body fluids?

Answer 17

Rifampicin

Question 18

Which antibiotics can increase the potency and duration of non-depolarising muscle relaxants?

Answer 18

Aminoglycosides- decrease pre-junctional release of ACh and reducing sensitivity post junctional ACh

ie. amikacin, gentamicin, neomycin sulfate, streptomycin, and tobramycin.

Question 19

Which antibiotics can cause discolouration in children’s teeth?

Answer 19

Tetracyclines

Question 20

Which antibiotic can cause Red Man Syndrome and what is it?

Answer 20

Vancomycin- causes histamine release and associated symptoms include widespread rash known as red man syndrome.

Question 21

Which Abx are sensitive to B-lactamase enzymes produced by resistant bacteria?

Which are resistant?

Answer 21

Piperacillin and Benzylpenicillin are sensitive.

Meropenem (very) and Flucloxacillin (moderately) are resistant.

Question 22

Can Amphotericin B be orally administered?

Answer 22

No, only IV

Question 23

What antibiotics can be both bacteriocidal or bacteriostatic?

Answer 23

Macrolides such as a Azithromycin/ clarithromycin/ erythromycin etc depending on their plasma concentration.