Antimicrobial Resistance

Question 1

What are the consequences of AMR on animal & public health?

Answer 1

-increased patient mortality & morbidity
-risk of zoonotic transmission

Question 2

What are the economic consequences of AMR on animal & public health?

Answer 2

-more visits, lab test & therapies
-prolonged hospitalization
-reduced weight gain
-loss of customers/reputation by vet
-costs for hospital/farm decontamination
-cost for surveillance & intervention program

Question 3

Define antimicrobial resistance (microbiology).

Answer 3

-bacterial strains survive at higher antibiotic concentrations compared w the wild type pop.
>ex: bacterial pop w no resistance gene/mutation conferring resistance within the species
-ability of microbes to grow in presence of a drug that normally kills/limit growth

Question 4

Define antimicrobial resistance (clinically).

Answer 4

-bacterial ability to survive antimicrobial therapy & cause therapeutic failure

Question 5

What are the 2 diff antimicrobial resistance strategies?

Answer 5

1. Stop antibiotic from reaching its target at a high conc
2. Modify/bypass target that the antibiotic inhibits

Question 6

Describe how to stop the antibiotic from reaching target.

Answer 6

-efflux pumps
-decrease permeability of membrane that surrounds bacterial cell wall
-destroy the antibiotic = bacterial enzymes (EX: B-lactamase)
-modify the antibiotic by adding diff chemical groups to antibiotics

Question 7

Describe how to modify/bypass the target.

Answer 7

-camouflage the target
-express alternative proteins
-reprogram target = some bacteria can produce a diff variant
>EX: vancomycin-resistant bacteria make a diff cell wall compared to susceptible bacteria

Question 8

Describe intrinsic resistance.

Answer 8

-naturally acquired trait
-species or genus specific

Question 9

Describe acquired resistance.

Answer 9

-by mutation in existing DNA
-by new DNA via transformation, transduction, conjugation

Question 10

Describe antibiotic selection.

Answer 10

-bacteria that have acquired resistance & pass it to other bacteria
-antimicrobials kill bacteria that have no resistance = increase share of resistant bacteria

Question 11

Describe the antibiotic selection steps.

Answer 11

1. Bacteria cause an infection
2. Antibiotics given to kill bacteria
3. Bacteria cause illness = resist antibiotic treatment
4. Resistant bacteria multiply & cause infection = require antibiotics to treat & stop spread of infection

Question 12

Describe MRSA.

Answer 12

‘Methicillin Resistant Staphylococcus aureus’
-gram pos (animals & humans)
-acquired resistance gene (mecA) encoding for new PBP2A w low affinity to most B-lactams (pen & cephalosporins)
-major role in nosocomial infections
>community acquired MRSA
>hospital acquired MRSA
>livestock acquired MRSA

Question 13

Describe MRSP.

Answer 13

‘Methicillin resistant staphylococcus pseudintermedius’
-gram pos of dogs
-acquired resistance gene (mecA) similar to MRSA
-approx 70% skin cases & wound postsurg infections acquired in the clinic (nosocomial infection)
-some MRSP strains are multi-drug resistant bacteria (MDR) = may be resistant to all antibiotics

Question 14

Describe ESBL.

Answer 14

-gram neg = makes enzyme that can hydrolyze/inactivate most B-lactams, except carbapenems
-risk of food borne transmission
>gut commensal
>transfer from animal to human via eating meat
>upon eating, may colonize gut & transfer ESBL-encoding plasmids to resident E. coli

Question 15

Describe AMR.

Answer 15

-antibiotic selection = reduced efficacy over time
-AMR can’t be eradicated but only controlled through rational antimicrobial use

Question 16

Describe reduce overall antimicrobial consumption.

Answer 16

-disease prevention: hygiene, management, vaccination
-avoid prophylaxis
-avoid unnecessary therapy:
>viral infections (ex. URI)
>self limiting infections (ex. Acute diarrhea)
>disease conditions that require topical products (ex. Superficial pyoderma & wounds)

Question 17

Describe improving use of diagnostic testing.

Answer 17

-maximize use of cytology = guide antimicrobial choice for relevant disease conditions (ex. Otitis externa, skin & UTI)
-increase the use of culture & susceptibility testing

Question 18

What is the criteria for empiric therapy?

Answer 18

-use of first choice drugs defined by national/international animal & disease guidelines
-disease specific antibiotic formularies
>take into account local patterns of antibiotic use
>local AMR trends
>availability of antimicrobials on market
>national regulations on antimicrobial use
>cultural differences

Question 19

Describe prudent use of 2nd line CIA.

Answer 19

-minimize empiric use of CIAs (esp broad spec = select for MDR bacteria & should be preserved for difficult infections)
>3rd & 4th generation cephalosporins
>macrolides (livestock/horses)
>fluoroquinolones

Question 20

Describe optimizing dosage regimes.

Answer 20

1. Shoot high = high dose
   -concentration dependent drugs
   -enhance therapeutic efficacy
   -prevent selection of resistant mutants
2. Shoot regular = give drug at regular intervals
   -time dependent drugs
   -enhance therapeutic efficacy
3. Shoot fast = treat earliest & shortest time

Question 21

Describe the measures for prevention & control of AMR.

Answer 21

Question 22

Describe antimicrobial stewardship.

Answer 22

-ASPs = improve antibiotic use to optimize treatment & patient safety & reduce adverse events of AMR
-ASPs = comprise education, clinical guidelines, pre-prescription approval, post-prescription approval, & computer based decision support
-establishment on ASPs require =
>coordination by specialist
>commitment by clinical staff
>collab w micro lab

Question 23

Describe hospital infection control.

Answer 23

-ICP
-routine practices
-hospital surveillance of pathogens & AMR