Cell Wall Inhibitors Flashcards
1
Q
State the MOA of beta lactamase (penicillin)
A
- Penicillin interfere the cell wall synthesis by binding with penicillin-binding-protein (PBPs) which are located in the bacteria cell wall.
- Penicillin-binding-protein (PBPs) are bacterial enzyme that involves in the cell wall synthesis and maintaining the morphological features of the bacterium.
- Penicillin-binding-protein (PBPs) leads to inhibition of peptidoglycans cross-linking.
- Penicillin inhibits transpeptidase catalyze reaction, thus hindering the formation of cross links essential for cell wall integrity.
- The structure of bacteria is distorted, allowing water to flow into the cells which cause it to bursts and eventually autolysis and the death of bacterial cell.
2
Q
Why penicillins are more active against Gram-positive organisms?
A
- Gram positive bacteria have a cell wall made up of thick peptidoglycans which easily transverse by penicillin.
- Gram negative bacteria have an outer lipopolysaccharide membrane surrounding the cell wall that present a barrier to water-soluble penicillin.
- However, the gram negative bacteria have protein inserted in the lipopolysaccharide layer that act as water filled channels called porins to permit transmembrane entry.
- thus, penicillin are more effective against gram positive bacteria.
3
Q
Classification of beta lactamase
A
- Natural penicillin
- Penicillin G (Acid labile)
- Penicillin V (Acid stable) - Antistaphylococcal penicillin
- Methicillin
- Oxacillin
- Nafcillin
- dicloxacillin - Extended spectrum penicillin (Acid stable)
- Ampicillin
- Amoxicillin (prophylaxis used by dentist for immunocompromised patients to prevent bacterial endocarditis) - Antipseudomonal penicillin
- ticarcillin
- piperacillin
4
Q
Adverse effect of beta lactamase
A
- Hypersensitivity (rashes & angioedema)
- Diarrhea
- Nephritis (Methicillin have the potential to cause acute interstitial nephritis)
- Nephrotoxicity
