Antibiotics & AMR Flashcards
What is a growth factor
Compounds that are required for the growth of some prokaryotes
What are growth factor analogues
Substances that are related to a growth factor but blocks the utilisation of the growth factor
How is sulpanilamide (an analogue) toxic to bacteria
By inhibiting synthesis of folic acid
How can prokaryotes become resistant to antibiotics
- Natural resistance
- Acquisition if resistance genes
- Mutation of antibiotic target
Causes of antibiotic resistance (6)
- Over prescribing of antibiotics
- Patients not finishing tx
- Over use in livestock & fish farming
- Poor infection control in hospitals & clinics
- Lack of hygeine & poor sanitation
- Lack of new antibiotics developed
Why are less than 1% of antibiotics developed clinically useful
- Toxic to host
- Inefficeint uptake by host cells
Bacteriocidal
Kill the bacteria
Bacteriostatic
stop bacteria from growing, immune response will kill it
Bacteriolytic
Lyse cells entirely
What do beta lactam antibiotics target in the bacterial cell
Inhibit cell wall synthesis
2 examples of beta lactams
- Penicillins
- Cephalosporins
what is penicillin G active primarily against
Gram pos bacteria
How does a bacteria become resistant to penicillin
- Bacteria produces penicillinase (beta lactamase)
- This cleaves the beta lactam ring of the antibiotic & renders it inactive
How do we try to combat beta lactamase
- With beta lactamase inhibitors
- Clavulanic acid is prescribed with penicillin to block beta lactamase
Cephalosporins vs penicillins
- Broader spectrum than penicillins
- More resistant to beta lactamases than penicillin
Specific mode of action of penicillins
- Inhibit cell wall synthesis
- Inhibit transpeptidation in peptidoglycan
Polymyxins mode of action
- Bind to lipid A portion of LPS (outer membrane of gram negs)
What is one of the only drugs we can use against MRSA and what is its mode of action
- Daptomycin
- Disrupts baterial membrane through formation of transmembrane channels
- Active against gram pos bact
