Chapter 20 - Antimicrobial Agents Flashcards
Five mechanisms of action
-cell wall
-protein synthesis
-nuclei acid
Spectrum
How many bacteria can they kill?
Narrow—> only kill one group ( eg gram n only)
Extended—> could kill more (eg gram n/p only)
Cell wall
Weakens cell, which bursts and dies
-assume that will target organism, since humans do not have a cell wall
What types attack cell wall
-penicillin
-cephalosporin
Penicillin
Destroys peptidoglycan, penicillin breaks peptide part of PG —> cell death—> recovery
-destroy beta lactam ring
Natural penicillin
Pen g or pen v
Pen g is given..
Given IM or IV
-gram positive (staph or strep)
Pen B
Can take orally
-resistant to stomach acid
Semi synthesis penicillin
Methicillin, oxacillin, ampicillin
MRSA
Methicillin
Narrow spectrum (gram positive)
Oxacillin
-resistant
Gram n/p
Ampicillin
Adverse effects of penicillin
Development of allergies
Cephalosporins
-resistant to B actin ring
-expensive
-drug of choice for tough to kill bacteria
-form generations (1 to 5 and improve each gen)
Adverse effects of cephalosporins
GI distress
Protein synthesis drugs
-Chloramphenicol
-erythromycin
-tetracyclin
-aminoglycosides
Chloramphenicol
-binds to. 50s subunit (bacterial ribosome)
-inhibit peptide bond formation
-structure very simple
-meningitis
Chloramphenicol structure
-can be made in lab
-penetrates BBB
Adverse effects of chloramphenicol
-aplastic anaemia
-grey baby syndrome
Aplastic anaemia
Suppress bone marrow production: fatal
Grey baby syndrome
Literally turn baby grey
Erythromycin
-Binds to 50s subunit
-larger molecule
-macrocyclic ring family
-choice of drug for allergy to penicillin
-can come in syrup form