Antibiotic resistance

Question 1

The 4 ways which antibiotics develop resistance..

Answer 1

1.Drug inactivation-beta lactamase (penicillin resistance)
2.Alteration of drug target- mutation in the DNA gyrase (resistance to quinolones)
3.Drug entry barrier- loss of porin (carbapenem resistance)
4.Drug efflux- pumping out tetracycline or fluconazole.

Question 2

Genetic mechanism of antibiotic resistance

Answer 2

Horizontal gene transfer- the process by which an organism incorporates genetic material from another organism without being the offspring of the donor organism.

Question 3

Plasmids..

Answer 3

Plasmids usually possess non-essential genes.
Plasmids may be essential for..
antibiotic resistance
virulence factors

Question 4

Insertion sequences and transposons..

Answer 4

Insertion sequences and transposons are genetic elements, if they are jumping around in a chromosome, that’s when they have the ability to mutate genes.
For example if a transposon jumps into a gene that is a porin, the gene will get disrupted which will result in porin loss which causes antibiotic resistance.

Question 5

How is horizontal gene transfer facilitated..?

Answer 5

Transduction- either specialised or generalised transduction. The bacteria phages will incorporate some fragment of the bacterial DNA into its own genome and it can transfer that when it infects a new cell.
Transformation- When bacteria die the DNA is released, there will be cells near by becoming competent and will take up DNA from the environment.
Conjugation- Bacteria have pheromones, a receptor picks up the pheromones and then it makes the sex pilus.