Infectious Diseases - Antibiotics And Resistance

Question 1

Class and mechanism of action of meropenem.

Answer 1

Carbapenem. Blocks PBP to inhibit cell wall synthesis

Question 2

Class and mechanism of action of ciprofloxacin.

Answer 2

Quinolone. Inhibits DNA topoisomerase

Question 3

Trimethoprim. Mechanism of action

Answer 3

Antifolate antibiotic. Disrupts dihydrofolate reductase

Question 4

Erythromycin. Class of action and mechanism.

Answer 4

Macrolide. Inhibits translocation of tRNA at the 50s ribosomal subunit.

Question 5

Docycycline. Class and mechanism of action.

Answer 5

Tetracycline. Competes with A site on the 50s ribosomal unit.

Question 6

VRE and mechanism of resistance

Answer 6

Vancomycin resistance is cause by an altered peptidoglycan terminus (d-ala-d-lac instead of d-ala-d-ala) resulting in reduced vancomycin binding (false binding sites) and failure to prevent cell wall synthesis.

Question 7

Mrsa and cause of resistance.

Answer 7

Staph Aureus produces PBP2a (instead of the usual penicillin binding protein) which avoids the inhibitory effects of the antibiotics due to MecA gene.

Question 8

ESBL. Cause of resistance.

Answer 8

Plasmid mediated transmission. Induced by repeated exposure to beta lactam antibiotics. Produces beta lactamases which hydrolyzes beta lactams.

Question 9

What are the new Amp c inducers and the recommended antibiotics?

Answer 9

Hafnia alvei
Enterobacter cloacae
Citrobacter freundii
Klebsiella aerogenes
Yersinia enterocolitica

Antibiotics- cefepime or meropenem