Mechanisms of Antibiotic Resistance (CP Lec 2)

Question 1

What does the M in MRSA stand for?

Answer 1

Meticillin (resistant Staphylococcus aureus)

Question 2

what is antibiotic sensitivity?

Answer 2

The susceptibility of bacteria to antibiotics

Question 3

Name 4 antibiotic resistnace mechanisms

Answer 3

1) no target (no effect)
2) reduced permeability (drug cannot get in)
3) Altered target (no effect)
4) Over-expression of target (effect diluted)
5) Enzymatic degradation (drug destroyed)
6) Efflux Pump - drug expelled

Question 4

Name 2 ways of testing sensitivity to antibiotics

Answer 4

1) Solid media (disk susceptibility testing)

2) Liquid media microtitre plate susceptibility testing

Question 5

What resistance mechanisms are encoded in a single gene?

Answer 5

• antibiotic modifying enzymes

- Altered antibiotic targets

Question 6

Name 3 ways in which Antibiotics resistance is transferred

Answer 6

-Plasmids via CONJUGATION
- HORIZONTAL transfer
(enabled by transposons and integrons, Dna sequences that are transferred between plasmids, or from plasmid to chromosome)
- VERTICAL transfer of resistance
(genes passed on to daughter cells

Question 7

what are the consequences of antibiotic exposure

Answer 7

1) Chance of survival enhanced by developement of resistance
2) resistant strain will outcompete sensitive strains
3) resistance increased by vertical transfer

Question 8

What enables horizontal transfer of resistance?

Answer 8

integrons and transposons