Antimicrobial Use in Veterinary Medicine Today and Tomorrow - Dr. Ron DeHaven , AVMA Executive Vice-President, from the 2012 NIAA One Health Approach to Antimicrobial Resistance and Use Symposium, October 26-27, 2012, Columbus, OH, USA. More presentations at: http://www.trufflemedia.com/agmedia/conference/2012-one-health-to-approach-antimicrobial-resistance-and-use

1. Antimicrobial
Use in Veterinary Medicine
Today and Tomorrow...
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W. Ron DeHaven, DVM, MBA
Executive Vice President and CEO
American Veterinary Medical Association

2. Definitions
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 Microorganisms
 Antimicrobials
 Antibiotics
 Antimicrobial Resistance

3. Uses of Antibiotics
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Animal uses currently approved by FDA
 Treatment
 Control
 Prevention
 Production Uses
(Growth Promotion/Feed Efficiency)

4. Sources and Regulatory Oversight
of Antimicrobials
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 Over-the-Counter (OTC)
 Producers, only as approved on label; can be feed or water
 Added to feed by a feed mill or producer as directed on the
FDA approved label
 Veterinary Feed Directive (VFD)
 Currently only 2 drugs are approved - florfenicol (Nuflor) and
tilmicosin (Pulmotil)
 OTC => VFD medically important antimicrobials in feed
 Prescription (Rx) –
 GFI 213 transitions medically important antimicrobials in
water from OTC to Rx and allows mechanism to seek
therapeutic claims for production use antimicrobials

5. Differences in Use
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 Human Medicine
 For treatment or prevention
 Physician determines indication and route of administration,
dose, frequency, and duration of treatment
 No restrictions on extra-label or "off label" uses
 Food Animals
 Drug only approved for specific indications, e.g., respiratory
disease due to Pasteurella multocida
 Only allowed at specific dosage, duration, frequency, and
route of administration
 Extra label uses heavily regulated

6. A Source of Controversy…
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 Antimicrobial use in food producing animals can serve as a
reservoir for antimicrobial resistance, i.e., the more we
expose the organisms to antimicrobials the more we give
them the opportunity to develop resistance.
 Although that may be true in a very simplified, general sense,
there is no clear scientific evidence of how, and to what
extent such exposure affects human health.

7. Additional Complexity
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 While plausible, there is no hard evidence that cases of
human infection with a resistant bacteria have been
caused by use of antimicrobials in food animals.
 There is little to no evidence that restricting or eliminating
the use of antimicrobials in food-producing animals
would improve human health or reduce the risk of
antimicrobial resistance to humans.

8. Benefits vs. Risk
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 Benefits of Antibiotics
 Animal welfare
 Prevent, control, & treat disease
 Food safety
 Healthy animals produce safer food
 Economic - Efficiency
 Environmental
 Disadvantages
 Antimicrobial resistant bacteria can develop

9. Impact of Animal Health on
Foodborne Risk
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 Healthy: Passed FSIS antemortem inspection
(not visibly ill)
 Some (~7%) had internal adhesions from previous
chronic infection
 Carcasses 90% more likely to be contaminated
with Salmonella
Photo credit: Hudson ISD FFA

10. Which is Preferred?
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 Less Use vs. More Use
 Lower dose in more animals (today)
 Higher dose in fewer animals (tomorrow?)
 Stronger drugs?
 Or more culls?

11. Differing Approaches
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 Discontinue Use
 Although we may not know the degree of risk, why
should we take any chances?
 Let’s eliminate or reduce the use of antibiotics in animals
on the possibility that this is jeopardizing human health.
 Continue Use
 Let’s not take any action that is not based on a scientific
risk assessment.
 The benefits to animal health, welfare, and food safety
outweigh the risks to human health based on risk
assessments done to date.
 Novel Approach ?

12. We Need a Collaborative Approach!
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13. AVMA's Current Approach
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 Judicious use of antimicrobials
 Maximize benefit, minimize risks
 Supports veterinary involvement in any use of
antimicrobials
 Actions to limit use should be based on:
 Available scientific research
 Risk-based assessments

14. Preservation of Antibiotics for Medical
Treatment Act (PAMTA)
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 Purpose
 Preserve the effectiveness of medically important
antibiotics used in the treatment of human and animal
diseases by reviewing the safety of certain antibiotics for
nontherapeutic purposes in food-producing animals.
 Nontherapeutic Use
 Use of the drug as a feed or water additive for an animal
in the absence of any clinical sign of disease in the
animal for growth promotion, feed efficiency, weight gain,
routine disease prevention, or other routine purpose.

15. AVMA’s Position on PAMTA
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 Not supported by science (based on
AVMA’s interpretation)
 Lacks risk-based assessments
 Has potential to eliminate 2 or 3 of the 4
approved uses of antibiotics in animals
 Animal welfare implications

16. Greater Veterinary Oversight
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 Some believe this is the way to go – supported
by market research
 General agreement within AVMA (We think!)
 Workforce shortage issue (some disagree)
 VFD is primary vehicle for greater oversight in
antimicrobials in feed
 Degree of oversight proportionate to risk
 AVMA would do all we can to make it work!
 Veterinary Oversight Steering Committee

17. Legislation versus Regulation
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 Legislation
 Less opportunity for scientific input & evaluation
 Can be more politically motivated
 Regulation (rulemaking process)
 Provides months/years for input
 More of a deliberative process
 Statutory authority already exists

18. FDA-CVM Perspective
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 Innovative use of VFD
 Supportive of and recognition of the importance of
treatment, control, and prevention
 Phase in greater veterinary oversight
 Phase out growth promotion/feed efficiency
 Data needed – Is Growth Promotion really
prevention?

19. So, where are we headed?
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20. Pathogenesis of Baldness
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21. So, where are we headed?
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 More Veterinary Oversight
 Workforce concerns
 More responsibility and more credit - yet also
more blame
 Role of Veterinarians? Huge!

22. ®