Antibiotics

Question 1

Penicillin

Answer 1

Cell wall inhibitors: contain b-lactam ring. Inhibit peptidoglycan crosslinking

Question 2

Quinolone

Answer 2

Inhibit nucleic acid synthesis: inhibits topoisomerase II ligase domain. This coupled with contain topoisomerase leads to DNA framentation in nuclease activity.
Gram (-) target DNA gyrase.
Gram (+) target topoisomerase IV

Question 3

Cycloserine

Answer 3

Cell wall inhibitor: Inhibits alanine racemase (produces D-alanine) and D-alanine ligase (joins two residues of D-alanine)

Question 4

Aminoglycosides

Answer 4

Protein synthesis inhibitor: Causes 30S ribosomes to prematurely release peptides

Question 5

Tetracycline

Answer 5

Protein synthesis inhibitor: Inhibits the elongation of polypeptides at 30S ribosomes

Question 6

Sulfonamides

Answer 6

Antimetabolites: Competitive inhibitor of dihydropteroate synthase and disrupts folic acid synthesis.

Question 7

Ethambutol

Answer 7

Cell wall inhibitor: Inhibits arabinogalactin synthesis which leads to an increased permeability of the cell wall

Question 8

Isoniazid

Answer 8

Cell wall inhibitor: Inhibits the synthesis of mycolic acids

Question 9

Rifampin

Answer 9

Nucleic acid synthesis inhibitor: Prevents transcription by binding DNA dependent RNA polymerase.

Question 10

Ethionamide

Answer 10

Cell wall inhibitor: Inhibits the synthesis of mycolic acids

Question 11

Glycylcycline

Answer 11

Protein synthesis inhibitor: Prevents initiation of protein synthesis at 30S ribosomes by binding to it

Question 12

Macrolides

Answer 12

Protein synthesis inhibitor: Prevents the elongation of polypeptides at 50S ribosomes.

Question 13

Daptomycin

Answer 13

Cell wall inhibitor: Causes the cytoplasmic membrane to depolarize rapidly causing a huge efflux of ions which leads to inhibition of protein, DNA, and RNA synthesis

Question 14

Bacitrin

Answer 14

Cell wall inhibitor: Prevents the transportation of NAG-NAM units outside

Question 15

Oxalidinone

Answer 15

Protein synthesis inhibitor: Prevents the initiation of protein synthesis at 50S ribosomes.

Question 16

Vancomycin

Answer 16

Cell wall inhibitor: Prevents crosslinking and formation of NAG-NAM peptides

Question 17

Ketolides

Answer 17

Protein synthesis inhibitor: Prevents the initiation of protein synthesis at 50S ribosomes

Question 18

Polymyxin

Answer 18

Cell wall inhibitor: The hydrophobic tail penetrates both the outter and inner membranes of gram negative bacteria and damages it. It’s actions are detergent-like.

Question 19

Cephalosporin

Answer 19

Cell wall inhibitor: Prevents peptidoglycan crosslinking

Question 20

Rifabutin

Answer 20

Nucleic acid synthesis inhibitor: Blocks DNA-dependent RNA-polymerase. Effective against gram +, -, and mycobacteria.

Question 21

Metronidozole

Answer 21

Nucleic acid synthesis inhibitor: When it is reduced by anaerobes or protozoa to nitroso intermediates, it will form sulfinamides and thioether linkages with cystein-bearing enzymes. This deactivates these critical enzymes

Question 22

Cephamycin

Answer 22

Cell wall inhibitor: Prevents crosslinking of peptidoglycan

Question 23

Carbapenem

Answer 23

Cell wall inhibitor: Prevents crosslinking of peptidoglycan

Question 24

Dapsome

Answer 24

Antimetabolites: Competitively competes with para-aminobenzoate for the active site of dihydropteroate synthase.

Question 25

Clindamycin

Answer 25

Protein synthesis inhibitor: Prevents the enlongation of peptides at 50S ribosomes.
Usually used to treat infections with anaerobic bacteria and also malaria.

Question 26

Trimethoprim

Answer 26

Antimetabolite: a pyrimidine inhibitor of dihydrofolate reductase and disrupts folic acid synthesis

Question 27

Streptogramin

Answer 27

Protein synthesis inhibitor: Prevents the elongation of peptides at 50S ribosomes.
Effective against vancomysin-resistant enterococcus and staphylococcus aureus.

Question 28

Monobactum

Answer 28

Cell wall inhibitor: Prevents crosslinking of peptidoglycan

Question 29

Synergistic combination

Answer 29

B-lactam drugs (penicillin, cephalosporin, cephamycin, carbapenem, and monobactam) with B-lactamase inhibitors (tazobactam, clavulanic acid, and sulbactam) enhance the effects of protein synthesis inhibitor (e.g. aminoglycosides)

Question 30

Antagonistic combination

Answer 30

Certain drugs like chlortetracycline can induce B-lactamase effects rendering penicillin less effective

Question 31

Bactericidal (not bacteriostatic) antiobiotics

Answer 31

Penicillin, cephalosporin, aminoglycoside, vancomysin, fluoroquinolone, metronidazol