Mechanisms of Action of Antibiotics

Question 1

Name the three methods of antibiotic action

Answer 1

1. Inhibition of cell wall synthesis
2. Inhibition of protein synthesis
3. Inhibition of nucleic acid synthesis

Question 2

Name the two types of drugs involved in inhibition of bacterial cell wall synthesis

Answer 2

Beta-Lactams and Glycopeptides

Question 3

Give two examples of Beta-Lactams

Answer 3

Penicillins and Cephalosporins

Question 4

How does interruption of cell wall synthesis lead to bactericidal action?

Answer 4

Damaged cell walls cause autolytic cells to destroy the bacteria

Question 5

Give two examples of glycopeptides

Answer 5

Vancomycin and teicoplanin

Question 6

Glycopeptides only act on what kind of bacteria?

Answer 6

Gram positive

Question 7

Glycopeptides are not absorbed in the GI tract - how are they administered?

Answer 7

Paraenterally

Question 8

What is a common problem with vancomycin?

Answer 8

Toxicity

Question 9

What are the side effects of vancomycin?

Answer 9

Otoxicity, Nephrotoxicity and skin rashes

Question 10

Describe the relative toxicity of teicopanin

Answer 10

Less toxic

Question 11

Name the four groups of antibiotics that target protein synthesis

Answer 11

Macrolides and tetracyclines, oxazolidinones, aminoglycosides, cyclic lipopeptides

Question 12

Give an example of an aminoglycoside

Answer 12

Gentamicin

Question 13

Gentamicin is used to treat what type of bacteria?

Answer 13

Gram negatives

Question 14

How is gentamicin administered?

Answer 14

Injectable, not oral

Question 15

Describe the action of gentamicin on staphs. and streps.

Answer 15

Most Staph. spp are susceptible but not Strep. spp

Question 16

Give a sound example of a cyclic lipopeptide

Answer 16

Daptomycin

Question 17

When is daptomycin used?

Answer 17

Used against serious MRSA cases on specialist advice

Question 18

Give an example of an oxazolidinone

Answer 18

Linezoid

Question 19

Linezoid has good activity against what infection?

Answer 19

MRSA

Question 20

Give examples of macrolides and tetracyclines

Answer 20

Erythromycin, clarithromycin and tetracycline

Question 21

When are macrolides used?

Answer 21

As alternatives to penicillin (gram positive infections)

Question 22

What infections show significant resistance to macrolides and tetracyclines?

Answer 22

Staph. aureus, pyogenes and Strep. pneumoniae

Question 23

What drug groups of antibiotics that inhibit nucleic acid synthesis?

Answer 23

Trimethoprim and sulphamethoxazole and fluoroquinolones

Question 24

Given an example of a fluoroquinolone

Answer 24

Cirpfloxacin

Question 25

Cirpfloxacin is useful against what type of bacteria?

Answer 25

Gram negative

Question 26

Why cannot cirpfloxacin be used in children?

Answer 26

Interferes with cartilage formation

Question 27

Trimethoprim is used on its own to treat what pathology?

Answer 27

UTI