Antibiotics

Question 0

Vancomycin

Answer 0

MOA: blocks cell wall synthesis
Blocks release of peptidoglycan precursor from bactoprenol & transglycosylation-no glycan chain extension
Target: bactoprenol precursor release & transglycosylation
Resistance: target site modify, innate dif terminal residue of pentapeptide than alanine

Question 1

B-lactams

Answer 1

MOA: inhibition of cell wall synthesis
Blocks transpeptidation reaction formation of peptidoglycan x-links
Targets: penicillin binding proteins
Resistance: inactivation by B-lactamases-mutations of PCP, access
Ex: penicillin, monobactams, carbapenems, cephalosporins

Question 2

Bactracin

Answer 2

MOA: Blocks cell wall synthesis by blocking dephosphorylation of bactoprenol pyrophosphate and thus cycling of bactoprenol carrier
Target: phosphorylation site of bactoprenol pyrophosphate
Resistance is not common

Question 3

Polymixin

Answer 3

MOA: alter permeability of susceptible G- bacteria by interacting with LPS and phospholipids
Target: LPS and phospholipids on G- bacteria
Resistance not common

Question 4

Daptomycin

Answer 4

MOA: binds to cell membranes of susceptible G+ bacteria depolarizing and disrupting ion gradient
Target: cell membranes of G+ bacteria
Resistance is not common

Question 5

Isoniazid

Answer 5

MOA: block mycolic acid synthesis
Target: mycolic acid synthesis
Resistance: due to reduced uptake and modification of target sites
Mycobacterium cell wall inhibitor

Question 6

Collistin

Answer 6

MOA: alter permeability of membranes of susceptible G- bacteria by interacting with LPS and phospholipids
Target: LPS and phospholipids on G - bacteria
Resistance not common

Question 7

Ethionamide

Answer 7

MOA: block mycolic acid synthesis
Target: mycolic acid synthesis
Resistance: due to reduced uptake and modification of target sites
Mycobacterium cell wall inhibitor

Question 8

Ethambutol

Answer 8

MOA: interferes with arabinogalactan synthesis
Target: arabinogalactan synthesis
Resistance due to reduced uptake and modification of target sites
Mycobacterium cell wall inhibitor

Question 9

Cycloserine

Answer 9

MOA: interferes with alanine synthetase and racemase
Target: inhibits alanine synthetase/racemase
Resistance use to reduced uptake and modification of target sites
Mycobacterial cell wall inhibitor

Question 10

Aminoglycosides

Answer 10

Streptomycin kanamycin amikacin gentamicin tobramyci neomycin
Irreversible inhibition of protein synthesis, inhibit elongation
Actively transported into cells, requires oxidative phosphorylation
Target: ribosomes 30s subunit
Resistance: innate target site mutation, access- mutation in active transport, and permeability

Question 11

Tetracyclines

Answer 11

Doxycycline, minocycline
Reversible inhibition of protein synthesis-blocks tRNA
Target:ribosomes
Resistance: access decreased uptake or increase effluent pumps
Binding: production of a protein that binds tetracycline and protects

Question 12

Chloramphenicol

Answer 12

MOA: blocks protein synthesis by inhibiting peptidyl transferase
Target: peptidyl transferase
Resistance: chloramphenicol acetyltransferase

Question 13

Macrolides

Answer 13

Erythromycin, Azithromycin
MOA: reverse inhibition of protein synthesis-blocks translocations
Target: Ribosomes
Resistance: access decreased permeability, target site modification ribosomal protein mutations, target site modification: methylation of rRNA

Question 14

Lincosamides

Answer 14

Clindamycin, lincomycin, linezolid
MOA: inhibition of protein synthesis blocks translocation
Target: ribosomes 50s subunit
Used for vancomycin resistant G+ organisms and multidrig resistant staphylococci

Question 15

Quinolones

Answer 15

Nalidixic, cliproflaxin, levofloaxin, ofloxacin
MOA: inhibition of DNA replication
Target: DNA gyrase and topoisomerase
Resistance: target site modification, mutations in DNA
Access: mutations in cell surface which decrease uptake

Question 16

Rifampicin aka rifampin

Answer 16

MOA: Inhibition of transcription
Target: DNA dependent RNA polymerase
Resistance: target site mutations in RNA polymerase

Question 17

Metronidazole

Answer 17

MOA: inhibition of DNA repair, bacterial nitro-reductase produces toxic product inhibits DNA repair mechanisms
Target: bacterial DNA and DNA repair systems
Resistance: mutations in reductases

Question 18

Trimeoprin

Answer 18

MOA-reversibly blocks steps in frolic acid synthesis
Target: frolic acid synthesis
Access: decreased permeability
Bypass or target site modification

Question 19

Sulfonamides

Answer 19

MOA: reversibly block steps in folic acid synthesis
Target: folic acid synthesis
Access: decreased permeability, bypass or target site modification