Zusammenfassung der Ressource
Antibiotic Targets
and modes
- Act on the Cell Wall
- relatively inexpensive
- non-toxic (can be administered in high doses)
- Penicillin
- contains bete-Lactam ring.
- beta-lactam inhibits the cross link between peptidoglycan
between NAM and NAG in the bacterial cell wall
- the bete-lactam ring binds with the enzyme
that produces these linkages
- the enzyme that hydrolises
these bonds continue to work
making the cell wall weak, the
osmotic pressure will continue
to rise eventually causing the
cell to burst and die
- Blocks the division of the bacteria
- usually on gram positive as there is a single cell wall
- Target Ribosomes
- targets protein synthesis
- Streptomycin
- cannot be administered orally but instead
by regular intramuscular injections
- binds to the 30s subunits of the bacterial
ribosome, this misleads the DNA codon
eventually causing inhibition of protein
synthesis
- by binding to the 30s subunit it interferes with the 50s subunit whcih associates with
mRNA. as a result an unstable mRNA strand is produced meaning the incorect AA
acids are coded for and therefore the worn proteing are produced causing cell death
- can be used on both gran negative
and positive making it a broad
spectrum antibiotic
- bacterial ribosomes are different than that of
humans meaning that it has specific toxicity
- Inhibit Nucleic Acid Synthesis
- Qunilones
- broad spectrum
- prevent DNA from unwinding and duplicating
- targets DNA gyrasa (topoisomerase) which causes
the DNA to unwind during DNA replication.
- used to treat certain infections (UTIs) caused by gram negative bacteria
- enter cells via pores therefore often
used to treat intracellular infections
- Anti-metabolites
- Sulfonamides
- humans require folic acid but the get it through diet and
we do not synthesis it therefor this is effective against
organismis that rely on folic acid synthesis
- selective toxicity
- competitive inhibition of
dihydropterate synthetase (DHPS)
- DHPS catalyses tconversion of PABA to
dihydropterate in folate synthesis pathway
- inhibit the production of folic acid an important metabolite
in DNA synthesis therefor cells are unable to divide
- inhibits the use of a metabolite which is part of normal metabolism
- can have a toxic effect on cells such as halt
growth and cell division (sometimes used in
cancer treatments)