Antibiotics 1

Question 1

Cycloserine

Answer 1

MOA: blocks incorporation of D-ALA into pentapeptide side chain

Question 2

Fosfomyicn

Answer 2

Prevents formation of NAM by inhibiting enol pyruvate transferase

Question 3

Moa of lysozymes

Answer 3

Hydrolysis of B1,4 glycosidic bond between the NAM of 1 monomer and NAG of adjacent monomer

Question 4

Vancomycin

Answer 4

Inhibits transglycosylatiotn by bindign to D-ALA,D-ALA,

preventing elongation and cross-linking peptidoglycan

Question 5

Risk factors for nosocomial MRSA

Answer 5

Hospitalization for 2 or more days in prev 90 days
Use of antibioitcs in prev 90 days
Chronic hemodialysis in prev 90 days
Documented prior MRSA colonization
Congestive heart failure
Gastric acid suppression

Question 6

Bacitracin

Answer 6

MOA: inhibits phosphates, inhibiting reuse of phospholipid required to accept NAP

Question 7

Beta-lactams

Answer 7

MOA: inhibits transpeptidation reaction

• transpeptidase (PBP) catalyzes a peptide-peptide bond fromation between the penultimate D-ALA and L-Gly (s aureus) or Lys (e coli)
• the terminal D-ALA is lost in the process

Question 8

Action of transpeptidase

Answer 8

transpeptidase (PBP) catalyzes a peptide-peptide bond fromation between the penultimate D-ALA and L-Gly (s aureus) or Lys (e coli)
*the terminal D-ALA is lost in the process

Question 9

Aminoglycosides

Answer 9

MOA: binds to 30s and causes mRNA codon to be misread

Interferes with the initiation complex of 30s and 50s

Question 10

Tetracyclines

Answer 10

Moa: binds to 30s and interferes with binding to tRNA to ribisomal complex (A site)

Question 11

Chloramphenicl

Answer 11

MOA: binds to 50s and inhibits formation of peptide bond
Inhibits PROKARYOTIC peptidyltransferase
*cycloheximide inhibits EUKARYOTIC peptidyl transferase

Question 12

Moa of macrolides

Answer 12

Blocks polypeptide exit channel or 50 s and prevents peptide chain elongation
“Inhibits translocatiotn”
Same with clindamycin and streptogramins

Question 13

Streptogramins

Answer 13

Bactericidal
Quinupristin-Dalfoprisitne
Arthralgia-myalgia syndrome

Question 14

List sulfonamides

Answer 14

Sulfamethoxazole
Sulfadiazine
Mavenide acetate
*moa: inhibits dihydropteroate synthase

Question 15

Used for community-acquired mrsa

Answer 15

Clindamycin

Question 16

Uses of clindamycin

Answer 16

Community acquired MRSA
Skin and soft tissue infections
Anaerobic infections
Backup vs G+ cocci

Question 17

Risk factors for community acquired MRSA

Answer 17

Cavitary infiltrate or necrosis
Gross hemoptysis
Neutropenia
Erythematous rash
Concurrent influenza
Young previously healthy status
Summer month onset