Hospital acquired infections and antibiotic resistance Flashcards
1
Q
Resistance:
A
ability of organism to replicate in presence of particular antibiotic at certain concentration
2
Q
Breaking point:
A
estimate of reasonable concentration that might be achieved clinically
3
Q
Minimal inhibitory concentration:
A
lowest concentration of antibiotic to inhibit growth
4
Q
Transposons:
A
integrate Chr DNA, allow transfer of genes from plasmid to Chr
5
Q
What diseases are caused by drug resistant bacteria?
A
see notes
6
Q
Give mechanisms of action of some antibiotics:
A
Selective toxicity – key differences between host and bacterium.
- Beta-lactams, vancomycin -cell wall
- Quinolones DNA replication
- Erythromycin, chloramphenicol & tetracycline-protein synthesis.
7
Q
What are mechanisms of antibiotic resistance?
A
- Altered target site may be because acquisition of alternative gene encoding a target modifying enzyme so gene performs some function but different structure so not susceptible to AB
- Inactivation of AB
- Need gene to break down AB
- Enzymes that hydrolyze or chemically modify AB
- Altered metabolism: re-engineer metabolic pathway so bypass stop that AB interferes with
- Increased production of enzyme substrate may be used to outcompete AB inhibit
- E.g increased PABA production confers resistance to sulphanomides
- Decrease drug accumulation/ Efflux
- Reduced penetration and/or increased AB efflux out of cell so doesn’t reach effective dose
8
Q
What are risk factors in hospitals?
A
- High number of all people - immunosuppression
- Crowded wards
- Pathogen presence
- Broken skin because surgical wound
- Indwelling devices
- AB therapy may suppress normal flora
- Staff transmission because in contact with many patients
9
Q
How to prevent drug resistance and nosocomial infections?
A
- Tighter prescription control
- Reduce broad spec AB
- Quicker identification of infections cause by drug resistant strains
- Combination therapy
- Knowledge of local strains/resistance patterns
