Micro - Antimicrobials (Mechanisms of Antibacterial Therapy)

Question 1

What is the mechanism of action of the following drugs: Penicillin, methicillin, ampicillin, piperacillin, cephalosporins, aztreonam, and imipenem?

Answer 1

Block cell wall synthesis by inhibition of PEPTIDOGLYCAN CROSS-LINKING

Question 2

Name 6 classes of antimicrobials that block cell wall synthesis by inhibition of peptidoglycan cross-linking.

Answer 2

(1) Penicillinase-sensitive penicillins (2) Penicillinase-resistant penicillins (3) Antipseudomonals (4) Cephalosporins (I-V) (5) Carbapenems (6) Monobactams

Question 3

What is the mechanism of action of Bacitracin and Vancomycin?

Answer 3

Block PEPTIDOGLYCAN SYNTHESIS

Question 4

What is the class of antimicrobials that block peptidoglycan synthesis? Give 2 examples of this.

Answer 4

Glycopeptides; (1) Bacitracin (2) Vancomycin

Question 5

What is the mechanism of action of Sulfonamides and Trimethoprim? How do their exact mechanisms differ?

Answer 5

Block nucleotide synthesis by inhibiting FOLIC ACID SYNTHESIS (involved in DNA methylation); Sulfonamides inhibit PABA conversion to DHF; Trimethoprim inhibit DHF conversion to THF

Question 6

Name the 2 antimicrobials that block nucleotide synthesis by inhibiting folic acid synthesis (involved in methylation).

Answer 6

(1) Sulfonamides (2) Trimethoprim

Question 7

What is the mechanism of action of Fluoroquinolones? What are 2 examples of Fluoroquinolones?

Answer 7

Block DNA TOPOISOMERASES; Ciprofloxacin, Levofloxacin, etc.

Question 8

Which 2 classes of antimicrobials blocks DNA topoisomerases? Give at least one example of each.

Answer 8

Fluoroquinolones - Cirofloxacin, Levofloxacin, etc.; Quinolone - Nalidixic acid

Question 9

What is the mechanism of action of Rifampin?

Answer 9

Block mRNA SYNTHESIS

Question 10

Which antimicrobial blocks mRNA synthesis (RNA polymerase)?

Answer 10

Rifampin

Question 11

What is the mechanism of action of Metronidazole?

Answer 11

DAMAGE DNA

Question 12

Which antimicrobial damages DNA?

Answer 12

Metronidazole

Question 13

What is the mechanism of action of the following antimicrobials: Chloramphenicol, macrolides, clindamycin, streptogramins (quinupristin, dalfopristin), linezolid?

Answer 13

Block protein synthesis at 50S RIBOSOMAL SUBUNIT

Question 14

Name 5 antimicrobials that block protein synthesis at 50S ribosomal subunit.

Answer 14

(1) Chloramphenicol (2) Macrolides (3) Clindamycin (4) Streptogramins (quinupristin, dalfopristin) (5) Linezolid

Question 15

What is the mechanism of action of Aminoglycosides and Tetracyclines?

Answer 15

Block protein synthesis at 30S RIBOSOMAL SUBUNIT

Question 16

Name the 2 antimicrobials that block protein synthesis at 30S ribosomal subunit.

Answer 16

(1) Aminoglycosides (2) Tetracyclines

Question 17

What is the mechanism of action of Sulfonamides? What are 3 examples of Sulfonamides?

Answer 17

FOLIC ACID SYNTHESIS (DNA methylation) - Inhibit conversion of PABA to DHF; (1) Sulfamethoxazole (2) Sulfisoxazole (3) Sulfadiazine

Question 18

What is the mechanism of action of macrolides? Give 3 examples of macrolides?

Answer 18

Block protein synthesis at 50S subunit; (1) Azithromycin (2) Clarithromycin (3) Erythromycin

Question 19

What is the mechanism of action of streptogramins? Give 2 examples of streptogramins?

Answer 19

Block protein synthesis at 50S subunit; (1) Quinupristin (2) Dalfopristin

Question 20

What is the mechanism of Aminoglycosides? Give 5 examples.

Answer 20

Block protein synthesis at 30S subunit; (1) Genatmicin (2) Neomycin (3) Amikacin (4) Tobramycin (5) Streptomycin

Question 21

What is the mechanism of Tetracyclines? Give 3 examples.

Answer 21

Block protein synthesis at 30S subunit; (1) Tetracycline (2) Doxycycline (3) Minocycline

Question 22

What is the mechanism of action of penicillinase-sensitive penicillins? What are 4 examples of such drugs?

Answer 22

Inhibit cell wall synthesis by blocking peptidoglycan cross-linking; (1) Penicillin G (2) Penicillin V (3) Ampicillin (4) Amoxicillin

Question 23

What is the mechanism of action of penicillinase-resistant penicillins? What are 3 examples of such drugs?

Answer 23

Inhibit cell wall synthesis by blocking peptidoglycan cross-linking; (1) Oxacillin (2) Nafcillin (3) Dicloxacillin

Question 24

What is the mechanism of action of antipseudomonals? What are 2 examples of such drugs?

Answer 24

Inhibit cell wall synthesis by blocking peptidoglycan cross-linking; (1) Ticarcillin (2) Piperacillin

Question 25

What is the mechanism of action of cephalosporins (I-V)? What are 5 examples (one from each generation) of such drugs?

Answer 25

Inhibit cell wall synthesis by blocking peptidoglycan cross-linking; (1) 1st - Cephazolin, etc. (2) 2nd - Cefoxitin, etc. (3) 3rd - Ceftriaxone, etc. (4) Cefipime (5) Ceftaroline

Question 26

What is the mechanism of action of carbapenems? What are 4 examples of such drugs?

Answer 26

Inhibit cell wall synthesis by blocking peptidoglycan cross-linking; (1) Imipenem (2) Meropenem (3) Ertapenem (4) Doripenem

Question 27

What is the mechanism of action of monobactams? What is an example of such a drug?

Answer 27

Inhibit cell wall synthesis by blocking peptidoglycan cross-linking; Aztreonam