Sun14November1246PM 44

A 35-year-old patient presents for surgery with peritonitis secondary to acute appendicitis. The surgeon asks you to administer a dose of metronidazole.

Which of the following mechanisms best explains the antibiotic action of metronidazole?

(Please select 1 option)

Interferes with bacterial DNA synthesis This is the correct answer

Interferes with bacterial protein synthesis Incorrect answer selected

Interferes with bacterial RNA synthesis

Interferes with bacterial energy metabolism

Interferes with bacterial cell wall synthesis

Explanation

Metronidazole is a nitroimidazole derivative used for the treatment of anaerobic bacterial and protozoal infections. It is a cytotoxic antibiotic. It is a prodrug that diffuses readily across the cell wall of microorganisms where it becomes reduced and promotes the formation of free radicals. These compounds covalently bind to host cell DNA resulting in the destabilisation of the amino acid helix. The resulting inhibition of nucleic acid synthesis results in cell death.

The principal mechanisms of antibacterial action include interference with:

Cell wall (peptidoglycan) synthesis

Penicillins

Cephalosporins

Vancomycin

Cell membrane integrity

Polymyxin B

Nucleic acid synthesis

Fluoroquinolones

Metabolic pathway (folate biosynthesis)

Sulphonamides

Trimethoprim

Protein synthesis

Aminoglycosides

Tetracyclines

Erythromycin/clindamycin

Chloramphenicol.

Answer Statistics

1

41%

2

23%

3

16%

4

10%

5

12%

Times answered: 272