Greatest threats to global health: antimicrobial resistance

Question 1

antimicrobial

Answer 1

a medicine that inhibits growth or destroys microorganisms

Question 2

antibiotic

Answer 2

type of antimicrobial that inhibits the growth of, or destroys, bacteria

Question 3

antimicrobial resistance (AR)

Answer 3

when bacteria, viruses, fungi and parasites change over time and no longer respond to medicines, making infections harder to treat and increasing the risk of disease spread, severe illness and death
- one of the largest threats to global health
- occurs naturally over time, accelerated by misuse of humans
- ineffective antimicrobial treatments = infections harder to treat
- longer time spent ill, higher medical costs, increased mortality = increased resources
- Global One Health problem (even plants!)
- creates ‘super bugs’ => microbes highly resistant

Question 4

3 ways antibiotics are used in animals
1. growth promotion

Answer 4

• intensive livestock production
• control infections indirectly: low sub-therapeutic dose (lower than what you need to treat infection)
• added to feed/water
• mechanism of action unclear, results in: increased weight gain, efficiency of feed utilization where you don’t need to use that much feed
• thought it’s because maybe antibiotics suppress bacteria in the gut => increase weight gain but not sure

Question 5

2. prophylactic use of antibiotics

Answer 5

• dsisease prevention for a disease not yet clinically diagnosed
• different from growth promotion => dose, infection expected (give amount needed to fight infection)
• common use: before,during, and/or after procedures causing injury; one animal diseased and whole herd is treated
• feed/water, oral/injectaable medications

Question 6

other words for prophylactic

Answer 6

preventative, preventive, safety, precautionary

Question 7

preoperative

Answer 7

from time of injury up to 2 hours before surgical incision

Question 8

perioperative

Answer 8

begins up to 2 hours prior to surgical incision and lasts until completion of the surgery
- antibiotics may need to be redosed during long procedures

Question 9

postoperative

Answer 9

begins at the completion of the surgical procedure and can last for variable duration

Question 10

3. treatment

Answer 10

antibiotics for a clinically diagnosed disease or illness
- clinical signs: observable symptoms of illness or disease
- vet diagnosed a must
- rule out infections that will not respond to antibiotics

• control infection and reduce risk of transmission

Question 11

consequences of antibiotic overuse

Answer 11

• expensive, increase price of treatment
• raises prices of animal products
• AMR reduces available antibacterial treatments for sick animals/people
  
  • increased losses => higher morbidity and mortality, reduced production/high financial loss
• poor animal welfare => longer time spent sick, increase risk of transmission, isolation where animal can get stressed and can increase susceptibility to other diseases
• transfer of antimicrobial resistant bacteria in animals, their waste, and surrounding environment (transfer to humans!)

Question 12

example of consequences of overuse

Answer 12

Salmonella
- linked to hamburgers made from cattle fed w/ chlortetracycline
- cattle had chlortetracycline-resistant bacterial salmonella which was carried to people
- bacteria doesn’t affect cattle

Swine dysentery
- caused by spiral shaped bacteria Brachyspira hyodysenteriae
- resistant to many drugs previously used for control
- large proportion of herd affected, persistent disease, recurring outbreaks
- led to animal welfare concerns, economic losses due to mortality, reduced growth
- more of a preventative approach => coming up w/ ways to reduce transmission like manure management

Question 13

alternative management strategies

Answer 13

increase biosecurity measures
- isolate new animals, perform health checks
- people wear PPE, masks, gloves, foot bath, booties which will help reduce pathogens from coming into facility

reduce animal stress, factors include:
- transportation b/twn facilities/farms
- overcrowding: reduce # housed per pen = more space per animal
- sudden changes to diet, temperature fluctuations, abrupt weaning, moving to different enclosures
- mixing of social groups
- poor stockmanship/rough handling => changes behavior, physiology which impacts research
- painful vet procedures performed w/o local anaesthetic/analgesia => risk of infection again

Question 14

more alternatives

Answer 14

• keep housing clean: sanitation, waste management
• create health plan: example is herd vx program
• improve disease detection: behavior is subtle and escalates
  
  • ex: early detection, precision livestock farming, definitive diagnoses (Culture & Sensitivity) to minimize impact of antibiotic on non-target bacteria
  • Culture & Sensitivity: swap location -> lab cultures & identity type -> add antibiotics and see which ones are effective
    
    • limitation: lab takes several days
• antibiotics should NOT be used to compensate for poor farm management practices
• prevention is better than cure

Question 15

Global action plans - who is involved

Answer 15

2015, World Health Assembly (WHO)
- increase awareness, provides alternatives
- ‘one health’ approach: many disciplines & experts
- UN’s Food and Agricultural Organization (FAO) & World Organization for Animal Health (OIE) adopted and supported global action

Question 16

global action plans - evidence based recommendations

Question 17

1. reduce use

Answer 17

overall reduction in use of ALL classes of medically important antimicrobials (all antimicrobials used in humans) in food-producing animals
- scientific evidence shows that restricting antimicrobials in food producing animals reduces prevalence of antimicrobial resistant bacteria

Question 18

2. complete restriction (A WAY TO REDUCE)

Answer 18

complete restriction of medically important antimicrobials in food producing animals for growth
- evidence shows it reduces antimicrobial resistant bacteria found in food-producng animals & their environments which can be transmitted to humans

Question 19

3. complete restriction (A WAY TO REDUCE)

Answer 19

of ALL classes of medically important antimicrobials in food producing animals for prevention of diseases NOT CLINICALLY DIAGNOSED
- evidence shows restriction of prophylactic antimicrobial use has relatively small impact on animal health and welfare
- also shows it reduces transmission of AMR bacteria to humans

Question 20

4. conditional recommendation

Answer 20

antimicrobials critically important for humans (sole or limited therapy options), or highest priority critically important (used to treat serious infections in humans in which that class of antibiotics is the sole therapy) should not be used to treat food-producing animals
- exceptions to prevent harm to animal health and welfare, judgement must be made by a vet AND there must be evidence to demonstrate that selected drug is the ONLY treatment option

ex: bacterial culture and sensitivity
- culture: a test to find germs that cause an infection
- sensitivity: test that checks to see which antibiotic works best for treatment

Question 21

best practice statements

Answer 21

1. any new class of antimicrobials or combination developed for use in humans will be considered critically important for human medicine unless categorized otherwise by WHO
2. medically important antimicrobials that are not currently used in food production should not be used in the future in food production including food-producing animals or plants
   - basically not labeled for animals = CANNOT USE

EXCEPTION: evidence to demonstrate only option for infection is a medically important antimicrobial, then only a vet can choose to treat animals w/ this antimicrobial