Antimicrobial Resistance Flashcards
Name the forms of natural resistance to antibiotics
- No drug target present
- Drug target not accessible
- Developmental structure/state (spore, persister cells)
- Metabolism
In what sort of community do most bacteria exist?
Biofilms
What is a persistor cell?
*hint: the persist…
- Cells with extreme tolerances
- Metabolically inert
- Survive treatment and reinfect the patient
What are planktonic bacteria?
Bacteria that are not bound to a biofilm or adhered to a surface
Why are many persister cells unaffected by antibiotics?
Due to their very low metabolic activity
Give the stages of the evolution of antibiotic resistance
1) Genetic variation
2) Selection pressure (e.g. antibiotic)
3) Evolution of resistance
4) Gene transfer (resistance spreads)
Describe how genetic variation arises to cause the evolution of resistance
Mutations:
Rapid growth means more mutations
Most unsuccessful, rarely is beneficial
List the types of horizontal gene transfer for bacteria
- Bacterial transformation
- Bacterial transduction
- Bacterial conjugation
Describe horizontal gene transfer via bacterial transformation
- Donor cell releases DNA into the extracellular space
- Recipient cell accepts it
- May add bits to its genome
Describe horizontal gene transfer via bacterial transduction
- Cell is infected by a bacteriophage
- Phage transports some bacterial DNA to new cell
Describe horizontal gene transfer via bacterial conjugation
- Donor cell forms a sex pilus with recipient cell
- Plasmid transfer
Name to 2 main types of resistance
- Cross resistance
- Multiple resistance
Describe cross resistance
- Single mechanism has become resistant
- Effects closely related antibiotics
Describe multiple resistance
- Multiple mechanisms are resistant
- effects unrelated antibiotics
List antimicrobial resistance mechanisms
- Altered drug permeability (influx or efflux)
- Drug inactivation
- Altered drug target site
- Replacement of a pathway
