Managing Expectations About Antibiotics - Dr. Peter Davies, College of Veterinary Medicine, University of Minnesota, , from the 2015 Allen D. Leman Swine Conference, September 19-22, 2015, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2015-leman-swine-conference-material

1. FDA Guidance 213
Managing expectations
Peter Davies BVSc, PhD
College of Veterinary Medicine
University of Minnesota, USA

2. FDA Guidances 209/213
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Vets Producers
Feed Industry

3. Expectations
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 Professional industry critics
 Government entities – FDA, CDC
 Not an act of congress
 Legislators
 Pressures to legislate further
 Scientists
 General consumers

4. Acting in the name of public health
and/or better ‘stewardship’
 Changes motivated by perceived concerns of
AMU in animals generating AMR in bacteria
infection people
 Link between availability and abuse
 Greater oversight = less abuse?
 Less use = less abuse?
 Defining appropriate use
 Treatment >> Control >Prevention>Production
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5. What does success look like?
 Does compliance = success?
 Non-compliance does = failure!
 Does less AMU = success?
 Measurement
 Public Health Benefits/Risks
 Residues
 Resistant foodborne pathogens
 Other resistant organisms
 Lower incidence of resistant infections
or treatment failures
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6. Expectations for banning of AGP in
Denmark and EU
 Reduction of antibiotic use in food animals
 Minimal impact on production
 Reduction of antibiotic resistance
 Animal isolates
 Human isolates
 Reduced risk to human health
 Zoonotic and foodborne pathogens
 Commensal organisms and animal pathogens

7. Aggregate antimicrobial use in Danish
swine industry
• Lowest use was in 1999 before weaned pig ban
• Replacement of AGP with therapeutic use
Avoparcin ban and
ban on vet sales
AGP ban
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8. Antimicrobial use in pigs in Holland
(MARAN)
• Use peaked in 2008 after 2006 ban
• Increased enteric disease in weaned pigs
• Marked reduction later due to government mandate

9. DANMAP 2004
Antimicrobial resistance in Salmonella

10. DANMAP 2012
Antimicrobial resistance in Salmonella

11. AMR in Salmonella in pigs
DANMAP 1998/2012

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What about MRSA?
(Methicillin resistant S. aureus)
 Emergence of ‘livestock associated’ MRSA since
2004
 Many countries
 Hot subject in current discussions
 Use of growth promotants often blamed
 Despite complete absence of evidence

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Growth promotants as the culprit?
MRSA cases in Denmark (all types)
Ban of AGP
In finishers
Ban of AGP
in nurseries
MRSA ST398
detected
DANMAP 2010

14. Residue violations in market hogs
Unheralded success!
 1978: violative residues (USDA)
 5.6% for antibiotics
 9.7% for sulfonamides
 2011: Sulfonamides
 No violative sulfonamide residues in 204 tests
 2008-2011: Antibiotics
 No violative antibiotic residues in 1,199 market hogs
 2011: 1 in 11,509 ‘inspector generated’ tests (FAST)

15. Expectations for food safety
 Major route for resistance transfer to public
 Salmonella
 Campylobacter
 Listeria, Yersinia, E. coli, ….
 Major impetus for restrictions on AMU
 Salmonella in particular (DT104 and other MDR)
 Denmark and EU
 CDC in the 1990’s
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16. Multidrug Resistance Among Salmonella Isolates
NARMS, 1997-2010
• Decrease in MDR Salmonella isolates in humans
• No marked change in pigs or other animals

17. Do we have any useful public health
measure?
 Residues already close to zero
 Reducing prevalence of MDR Salmonella already
 No reliable measure re human illness
 Focus likely to be on AMU
 Industry benchmarking
 Understanding purpose of use
 Defining meaningful metric
 Professional industry critics can never be satisfied
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