antibiotic resistance

Question 1

define resistance

Answer 1

the previously susceptible organism cannot be inhibited with clinically achievable concentrations

intermediate resistance can be treated with an increased dose

Question 2

what is intrinsic resistance

Answer 2

when all strains of a species are resistant

Question 3

what is the therapeutic index

Answer 3

dose needed for harm - dose needed to treat

Question 4

describe enzymatic destruction

Answer 4

the drug is destroyed by subtraction or addition to the drug by an enzyme

Question 5

name some resistance mechanisms

Answer 5

efflux
impermeability
alternative pathway
altered binding site

Question 6

what does alternative pathway mean

Answer 6

the bacteria finds a different way to synthesise the molecule

Question 7

what does alternative binding site mean

Answer 7

the binding site on the enzyme which the drug normally inhibits is changed so the drug cannot bind

Question 8

describe quinolone resistance

Answer 8

single point mutation gives low level resistance
2 point mutations give high level resistance
gemifloxacin is active against both mutants (dual targeting)

Question 9

what are 3 ways that mutations can be shared

Answer 9

transposons and integrons
conjugation
transformation

Question 10

what is a superbug

Answer 10

an organism that has gained resistance to critical or multiple antibiotics

Question 11

how are resistant bugs treated

Answer 11

culture
susceptibility testing
use the most bactericidal drug available
consider combinations