1. No category

Veterinary medicine and the use of
antibiotics in agriculture
Björn Bengtsson
National veterinary Institute
Use of antibiotics leads to resistance
Nobel Lecture 1945
“But I would like to sound one note of
warning.”
“By exposing his microbes to non-lethal
quantities of the drug make them
resistant.”
Sir Alexander Fleming
1881-1955
Resistance in bacteria from animals – does it
matter?
Animal health perspective
Therapeutic failures!
→ MRSP (meticillinresistent Staphylococcus pseudintermedius)
→ Escherichia coli
→ Brachyspira
→ Staphylococcus aureus
→ Pasteurella/Mannheimia
→…
Human health perspective
Similarities
• The same antibiotics
• The same resistance genes
• Sometimes the same bacteria
Consensus - use in animals a threat to humans!
• WHO, OIE, FAO …..
• “… clear evidence of adverse human health
consequences due to resistant organisms resulting
from non-human usage” (WHO,INFOSAN Note No. 2/2008)
Difficult to quantify the consequences and risks!
Diverging opinons on when to act
• A risk must be well documented
• A risk is possible – ”precautionary principle”
• Antibiotics should not be used in animals
• Large economical incentives
– Food producers
– Pharmaceutical companies
To comprehensively describe how antibiotics
are used in animals is complex
• Several animal species
• Different systems for food-production
• Legal regulations vary between countries
• Access to antibiotics varies between countries
• Data on use is largely lacking
Food-production
Companion/Sports
Companion/sport animals are kept for emotional &
economical reasons
• Individual animals are valuable
• Advanced healthcare
• Individual treatment
•…
Food-animals are kept for economical reasons
• Costs must be motivated
• Withdrawal period for slaughter/milk/eggs
• Group-treatment common
• ”Antibiotics cheaper that prophylaxis”
• Growth promotion
Under veterinary control?
• In EU veterinary prescription
is required
• More liberal elsewhere!
How are antibiotics used in animals?
• Individual animals
• Groups of animals
• Terapy
• Prophylaxis
• Metaphylaxis
• Growth promotion
Individual animals
Orally
– Dogs/Cats
– Horses
– Pigs
90 %
Injection
– Cattle/Sheep
– Pigs
– Horses
Locally
– Ear/Eye/Skin
– Udder (cattle)
Long acting preparations
Cefovecin
3dje gen cefalosporin
Therapeutic for 14 days
Tulathromycin
Macrolide
Therapeutic for 7 days
Ceftiofur
3dje gen cefalosporin
Therapeutic for 7 days
Tetracyklin
“One dose delivers 3 days
of sustained therapy. Fewer
injections mean less labor
and animal stress”
Flock- or group-treatment
In feed or water
– Poultry
– Fish
– Pigs
– Calves
10 %
To treat healthy animals?
Prophylaxis
→ disease is expected in an animal or a group of animals
Metaphylaxis
→ disease has broken out in a group of animals
To increase growth with antibiotics?
• Low dose in feed promotes growth
• Several effects:
→ microbial
→ metabolic
→ nutritional
• Effective in”poor” environments
Banned in Sweden 1986 and in EU 2006
In USA these were alowed in 2005
•Bacitracin
•Bambermycins
•Carbaox
•Tetracyclines
•Monensin, Lasalocid
•Lincomycin
•Penicillin
•Tiamulin
•Tylosin (macrolide)
•Virginiamycin (streptogramin)
•…..
Creative thinking?
American Journal of Clinical Nutrition, 1958
What is used in animals?
• In general, classes used also in humans
… but some only to animals
→ Ionophores (coccidiostats)
→ Pleuromutilins
How much is used in animals?
Nobody knows!
In EU antibiotic use is monitored
Animals:
8 046 tonnes in 2012
(ionophores not included)
Humans:
3400 tonnes in 2012
70% to animals
PCU = population correction unit
Sales related to biomass of:
pigs, poultry, cattle, horses, rabbits, fish
The use varies between contries
2012
Mainly for group treatment
2012
Mainly Tetracycline, penicillins and sulphas
Tetracycline in different countries
2012
USA 2013: 10 354 tonnes for animals
62 %
3 900 tonnes for human use → 73 % to animals
What about the rest of the world?
EU (2012) and USA (2013) ≈ 19 000 tonnes
PNAS 2015
Global use 2010 estimated at 63 151 (±1 560) tonnes
• Based on few data sources
• Caution warranted!
We need antibiotics to treat animal
… but is too much used?!
• Probably!
EMA 2014
Resistance -the footprint of use
Tetracycline resistance in Escherichia coli
from healthy pigs 2011-2013
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Source: Svarm, DANMAP, EFSA, CIPARS
Ceftiofur to chickens – Dutil and others 2010
• Ceftiofur to chickens
• Voluntary withdrawal
• Partial reinstitutoin
To use less - is more!
• Improve animal health
─ healthy animals don’t need antimicrobials!
• Prudent use
─ only when necessary and as “narrow” as possible!
• Rational use
─ correct dose & duration!
Thank you
for your attention!