3.1 Antimicrobial Resistance

Question 1

What is intrinsic resistance?

Answer 1

the structure and/or biological characteristic of the microbe are not ameable to the effects of an antimicrobial

Question 2

What is antimicrobial resistance?

Answer 2

the acquired ability of a microbe to resistance the effects of an antimicrobial that once could have successfully treated the microbe

Question 3

What do we mean when we say AMR is binary?

Answer 3

it doesn’t creep up on you, it just happens out of nowhere

Question 4

Name the 3 sites of antiobiotic action

Answer 4

Bacterial Wall and Cell membrane
nucleic acid synthesis
protein synthesis

Question 5

What 6 antibiotics work on the bacterial cell wall and membrane?

Answer 5

penicillins
cephalosporins
carbapenems
monobactams
glycopeptides
polymyxins

Question 6

Name 3 sorts of antibiotics working on nucleic acid synthesis

Answer 6

Folate antagonists
DNA Gyrase (quinolones)
RNA Polymerase (Rifampicin)

Question 7

Why might we give HIV patients antibiotics which we know don’t work?

Answer 7

HIV will slow down its’ replication rate in order to survive

Question 8

What is the most common form of AMR?

Answer 8

enzyme release

Question 9

What is the principle of inducible resistance?

Answer 9

You have a bug which looks susceptible to the antibiotic…

however, it just switches a gene and sacrifices a bit of biological fitness to survive

Question 10

What are the 3 most commonly seen antibiotic resistant bacteria?

Answer 10

Methicillin resistant staphylococcus aureus (MRSA)
Vanomycin resistant enterococci (VRE)
extended spectrum beta lactamase producing enterobacteriaceae (ESBL)

Question 11

Why is ESBL so scary?

Answer 11

it produces enzymes which can break down our most broad spectrum antibiotics

Question 12

What are the 2 types of resistance in TB?

What are their survival rates in the UK?

Answer 12

multidrug resistanct TB (MDR-TB) 80%

extensively drug resistant TB (XDR-TB) 30-50%

Question 13

What is the definition of a multidrug resistant TB?

Answer 13

resistant to Rifampicin and Isoniazid

Question 14

Why can HIV resistance come and go?

Answer 14

it copies itself like mad, making lots of mistakes in the process, this means that it could remain dormant for a bit, and then if you give someone antibiotics all of a sudden it goes crazy

Question 15

name 2 M2 inhibitors, why are they important?

Answer 15

Amantadine, rimantadine

influenza A in humans is resistant to them

Question 16

Name 6 factors accelerating AMR

Answer 16

drug prescribing
drug access
drug quality
Veterinary use
global travel
the environment

Question 17

What 2 techniques do we use to assess in vitro antibiotic effectiveness?

Answer 17

Minimum inhibitory concentration (MIC)

resistance mutations

Question 18

What is MIC?

Answer 18

minimum in vitro concentration which an antibiotic can inhibit growth

Question 19

What is the significance of the difference between in vitro efectiveness and in vivo effectiveness?

Answer 19

in vitro effectiveness doesn’t necessarily translate to in vivo effectiveness

Question 20

Name 8 mechanisms of antimicrobial resistance

Answer 20

Enzymes
Outer membrane permeability
Inner membrane permeability
Mutations in target sites
Antibiotic efflux pumps
Target site protection
Target site overproduction
Alternative metabolic 
pathways

Question 21

What antibiotics have influenza A in humans shown resistance to?

Answer 21

M2 inhibitors

Question 22

define an XDR-TB?

Answer 22

resistant to:

rifampicin
isoniazid
flouroquinolones
an injectable agent