Microbio Chapter 20- Antimicrobial Agents Flashcards
What antimicrobial agents attack the cell wall?
- Penicillin
- Cephalosporins
What part of the cell wall do the agents attack?
P part of peptidoglycan layer
What do cell wall attacking agents cause
Osmotic lysis (cell dies)
What is the nucleus of Penicillin called?
Beta lactam ring
What two main types of penicillin?
a. Natural
b. Semisynthetic
What are the two types of natural penicillin?
PenG
PenV
How is PenG penicillin given?
Through injection
How is PenV penicillin given?
Taken orally
What are examples of semisynthetic penicillin?
Oxacillin, Ampicillin, Methicillin
What enzyme destroys the beta lactam ring of penicillin?
Penicillinase or Beta-lactamase
What are semisynthetic penicillin resistant to?
Penicillinase/beta lactamase. Resistance varies based on spectrum.
Example of a bacteria that produces Beta lactamase?
Staphylococcus aureus
Methicillin resistance?
Resistant
-MRSA strain (Methicillin resistant Staphylococcus aureus)
Oxacillin spectrum?
Narrow (only kill one group)
Ampicillin spectrum?
Broad (Could kill more bacteria)
What is a common adverse effect of penicillin?
Allergic reaction
What are cephalosporins resistant to?
Enzymes (e.g; Beta lactamase)
What is a problem associated with Cephalosporin manufacturing?
It is expensive because they require lab purification
How are the semisynthetic forms of cephalosporins named?
They are called by generation. 1st, 2nd, 3rd, 4th, 5th
What happens with each generation of semi forms of cephalosporins?
Each new generation gets broader and broader spectrum
What disease does 3rd gen cephalosporin treat?
Meningitis
What adverse effects are associated with Cephalosporins?
Mild GI tract symptoms
What antimicrobial agents inhibit protein synthesis?
- Chloramphenicol
2.Erythromycin
3.Streptomycin
4.Tetracycline
Why is Chloramphenicol CHEAPER to manufacture?
It naturally has a simple structure so it is less expensive to synthesise it chemically
What does Chloranphenicol’s simple structure allow it to do?
More easily penetrate tissues like the BBB
What can Chloramphenicol’s treat?
Meningitis
-bc it can penetrate BBB
What is a rare adverse effect associated with Chloramphenicols?
Aplastic Anemia
What adverse effect can occur if a woman takes chloramphenicol while pregnant?
Grey baby syndrome
How does Chloramphenicol inhibit peptide bond formation?
It binds to the 50s portion of the ribosome
What family does erythromycin belong to?
Macrolides
-Macrocyclic lactone ring structure
What drug can erythromycin be used as an alternative for?
Penicillin
e.g; allergy
What form can erythromycin be administered as?
Syrup form
-easy to take (orally)