Dr. Peter Davies - Managing Expectations About Antibiotics

FDA Guidance 213Managing expectations

Peter Davies BVSc, PhDCollege of Veterinary MedicineUniversity of Minnesota, USA

FDA Guidances 209/213

2

Vets Producers

Feed Industry

Expectations

3

Professional industry critics Government entities – FDA,

CDC Not an act of congress

Legislators Pressures to legislate further

Scientists General consumers

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

4

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

5

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

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 banF N

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

DANMAP 2004Antimicrobial resistance in Salmonella

DANMAP 2012Antimicrobial resistance in Salmonella

AMR in Salmonella in pigs DANMAP 1998/2012

12

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

13

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

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)

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

15

Multidrug Resistance Among Salmonella Isolates NARMS, 1997-2010

• Decrease in MDR Salmonella isolates in humans• No marked change in pigs or other animals

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

17