Antimicrobial Resistance

Question 1

Explain the main ways bacteria reduce antimicrobial efficacy?

Answer 1

Target modification - The biochemical interactions between the drug and its target are no longer effective, due to eg. changing the structure of the target
Innate resistance - The drug is not well targeted (immunity) or there is redunancy built in
Drug Efflux - Increasing expression of drug pumps on the cell membrane
Drug Inactivation - Enzymes or environmental conditions deactivate the drug

Question 2

What are the 3 main ways that bacterial populations develop antimicrobial resistance?

Answer 2

Inherent resistance of cells, mutation and selection of resistant cells, and horizontal transfer of genes conveying resistance.

Question 3

Explain what inherent resistance of cells means in terms of antimicrobials

Answer 3

The bacterial cells’ characteristics in relation to the drug make them resistant. The bacteria may not use the biological process that the drug targets, or the cell is impervious to the drug.

Question 4

Explain how mutations and selection of resistant cells leads to bacterial populations developing resistance to antimicrobials

Answer 4

Individual cells, due to random mutation, will be resistant to drugs. When exposed to the drugs, the resistant cells will survive, and reproduce, passing on their genes. The surviving cells have been selected for their resistance.

Question 5

Explain how horizontal gene transfer allows bacterial populations to develop antimicrobial resistance

Answer 5

Genetic material is transferred between organisms and species so the receipt gains characteristics associated with the material. This happens by uptake and incorporation of DNA with a resistance gene, phage (virus) mediated transfer of a resistance gene, or bacterial conjugation of a resistance gene - direct cell-cell contact