1 Antibiotics: Mode of Action

Question 1

Which class are levofloxicin & ciprofloxicin?

Answer 1

Quinilones

Question 2

Which class are clarithromycin and erythromycin?

Answer 2

Macrolides

Question 3

MOA of aminoglycasides?

Answer 3

Inhibition of 30S subunit in ribosome (impairs proof reading resulting in faulty proteins)

Question 4

What class are gentamicin and amikacin?

Answer 4

Aminoglycasides

Question 5

What class are vancomycin and teicoplanin?

Answer 5

Glycopeptides

Question 6

MOA of tetracyclines?

Answer 6

Bind to the 30S subunit (blokes binding of tRNAs thus inhibiting protein synthesis)

Question 7

MOA of macrolides?

Answer 7

Bind to 50S subunit of the ribosome (preventing bond formation and stopping protein synthesis)

Question 8

MOA of clindamycin?

Answer 8

Bind to 50S subunit of the ribosome (preventing bond formation and stopping protein synthesis)

Question 9

What class is clindamycin?

Answer 9

Lincosamide

Question 10

How do you know if ABx is static or cidal?

Answer 10

Bacterialcidal - anything related to penicillin & any aminoglycasides (gent and amik).
Quinilones - Cidal
Vanc is cidal against gram positive.

Static - all other (inc macrolides)

Question 11

MOA of B-lactams?

Answer 11

Inhibition of cell wall synthesis (Penicillin binding proteins in the cell wall). Preventing the cross linking of peptidoglycan

Question 12

MOA gylcopeptides?

Answer 12

Inhibition of cell wall synthesis (binds to peptidoglycan subunits)

Question 13

But AT 30 CEL at 50?

Answer 13

Aminoglycacides
Tetracyclines

Chloramphenicol
Clindamicin
Erythromyin (macrolides)
Linezolid

Question 14

MOA of collistin?

Specrum?

Answer 14

Disrupt membranes

Gram -ve only

Question 15

MOA of quinilones?

Answer 15

Inihibtion of neucleic acid synthesis:

Inhibits the activity of DNA gyrase and blocks DNA replication, killing the cell

Question 16

MOA of rifamycin?

Answer 16

Inhibits bacterial RNA polymerase activity and blocks transcription, killing the cell

Question 17

MOA trimethoprim?

Answer 17

Antimetabolite:

Inhibits the enzyme involved in the production of tetrahydrofolic acid

Question 18

MOA isoniazid?

Answer 18

Antimetabolite: Interferes with the synthesis of mycolic acid

Question 19

MOA metronidazole?

Answer 19

Inhibits nucleic acid synthesis by disrupting the DNA of microbial cells.