antibiotics Flashcards
penicillin mode of action
inhibits the last step of peptidoglycan synthesis, the transpeptidation reaction by binding to transpeptidase
inhibits pentaglycine- 5 glycines on lysine amino acids on chains
10 year old dose flucloxacillin
at least 250mg qds
augmentin clinical allergy caution
it is co-amoxiclav which can cause allergic response in patients allergic to penicillin
community acquired pneumonia treatment
clarithromycin 500mg BD 5 days
what is selective toxicity?
processes in bacteria which are
more susceptible to antibiotics than in the host
highly selective targets
unique biological targets
Inhibitors of Cell wall metabolism
Inhibitors of dihydropteroate synthetase
( only present in bacteria)
less selective targets
Inhibitors of protein synthesis
Inhibitors of dihydrofolate reductase
Inhibitors of transcription and DNA
replication
gram positive and gram negative difference
gram negative has both a thin, inner layer of
peptidoglycan and an outer
membrane but positive only has A dense layer typically composed of
numerous rows of peptidoglycan,
and molecules of lipoteichoic acid, wall
teichoic acid and surface proteins
describe sugar backbone of bacteria cell wall
alternating NAG and NAM sugars with peptide chains on latter with cosslinking between peptides forming call wall framework
why do some bacteria have d amino acids rather than l amino acids on end of peptide chains in cell wall
D-amino acids render the cell wall resistant
to the action of proteases which act on the more common L-amino acids
peptidoglycan cross-linking enzyme
transpeptidase on outer surface of the cytoplasmic
membrane
penicillin SAR
planar amide group for N lone pair to conjugate with carbonyl
b- Lactam ring more reactive than typical amide because ring system disfavours resonance of nitrogen lone pair
variable side chain
thiazolidine ring
cis stereochemistry essential
Bicyclic system essential
