Antimicrobial Resistance

Question 1

describe the impact antibiotic resistance has to public health

Answer 1

• makes individuals more susceptible to resistant bacteria

Question 2

what factors contribute to antibiotic resistance?

Answer 2

• over prescribing
• patients not finishing course
• over use in livestock and fish farming
• poor infection control in hospital and clinics
• lack of hygiene/poor sanitation
• lack of new antibiotics being developed

Question 3

list the main resistance mechanisms.

Answer 3

• mutations, evolution - adaptation
• no target
  bacteria may lack a target for the antibiotic - have to be modified
• inaccessible
  bacteria target may be inaccessible - not bind or decreased affinity
• elfflux pump - actively pump the drug out of the cell
• enzymatic degradation - drug can be chemically modified/destroyed
• horizontal gene transfer

Question 4

list the steps of horizontal gene transfer

Answer 4

1. conjugation
2. transformation
3. transduction
4. gene transfer agents

Question 5

describe each type of horizontal gene transfer

Answer 5

conjugation
-requires cell to cell contact
- DNA transferred directly from donor cell to recipient

transformation
- bacterial cell integrates fragments of extra cellular DNA by cell lysis

transaction
- viruses that infect bacteria
- transfer advantageous genes to microbial host

gene transfer agents
- require presence of bacteriophages
- carry random producing cell genome
- spread to recipient cell

Question 6

what are the 3 most commonly prescribed antibiotics by dentists?

Answer 6

amoxicillin
metronidazole
phenoxymethyl penicillin

Question 7

what 2 bacteria has there been resistance to amoxicillin reported in?

Answer 7

Veillonella spp
Prevotella denticola

Question 8

can species transfer resistant determinants between themselves?

Answer 8

there has been evidence

Question 9

how is there resistance to penicillin?

Answer 9

• oral streptococci produce b-lactamase
• cuts through bonds in penicillin and disables molecule

Question 10

what 2 bacteria are intrinsically resistant to metronidazole?

Answer 10

Eikenella corrodens
Aggregatibacter actinomycetemcomitans