Surveillance for antimicrobial resistance in enteric

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www.australianpork.com.au CDC Conference June 2017www.australianpork.com.au CDC Conference June 2017

CDC Conference,

Melbourne June 2017

Surveillance for

antimicrobial resistance in

enteric bacteria in Australian

pigs and chickensDr Pat Mitchell

R & I Manager

Production Stewardship APL

Dr Kylie Hewson

Assistant Executive Director

ACMF

www.australianpork.com.au CDC Conference June 2017

Pig producers ~ 1,400

400 producers ~90% of production

1,000 producers ~ 10% of production

Breeding herd size ~275,000 sows

Annual slaughter ~ 5.15 M

Kg Produced ~ 392,830,000

Kg Exported ~ 36,972,000 (9.4%)

Production systems:

Conventional housed ~ 90%

Outdoor housed ~10%Pork consumption: ~ 26kg

Fresh ~ 10kg

Processed ~ 16kg

Imported processed ~70%

7 Pig Specific Export Plants

Approx 15 others

China ~ 50M

USA ~ 6M

• Iowa ~1 million,

• North Carolina ~ 840,000

Canada~1.3M

Denmark~1.03M

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Location of Chicken Meat Production

Chicken Meat Produced (‘000 tones)

Key facts about the Australian chicken meat industry

34,500tonnes

Volume of chickenmeat exports pa

623.3millionNumber of

chickens slaughtered pa

46.2kg

Per capita consumption

Chicken produced

1,154,000tonnes

Chicken meatproduced pa

Slaughterings(million birds)

7 companies = >90% production

21 processing plants

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Antibiotic usage• Livestock industries

generally held responsible

• Tonnage roughly correct

*Animal 8,893,103 kg

*Human 3,379,226 kg

• Per head…not so much

319m people-10.59g/person

11.5b livestock-0.77g/head

14 x greater in

humans *FDA, 2012.

O’Neill 2016.


Resistance 101

• Doesn’t only occur because of use

• Some bacteria are naturally resistant

to certain antibiotics.

• Heavy metals (eg. Zn & Cu), disinfectants

promote the spread of antibiotic resistance

via co-selection.

• Can also become resistant

– by genetic mutation or

– by picking up resistance from other bacteria

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• 200 Samples taken at slaughter

– Pigs (Caecum), Chickens (Caecal

Tonsils)

• Estimate the prevalence of

AMR amongst commensals

– Two indicator commensals

E. coli, Enterococcus spp.

– Two others

Salmonella spp. & Campylobacter

spp.

Antimicrobial

surveillance project


Isolates

• UoA & Murdoch University antimicrobial susceptibility testing &

species identification using MALDI-TOF MS

• Antimicrobial susceptibility testing was performed using broth

microdilution Sensititre® cards.

• Two prevalence estimates: a) for the percent non-wild which

comes from EUCAST ECOFF and b) for the percent non-

susceptible which comes from the CLSI intermediate break point.

Pigs Chicken

E. Coli 200 206

Enterococcus 146 205

Salmonella 84 53

Campylobacter 171 204

TOTAL 601 668

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• MIC distributions currently being finalised

E. coli and Salmonella: amoxicillin/clavulanic acid, ampicillin,

cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, ciprofloxacin, florfenicol, gentamicin, colistin (replaces kanamycin), streptomycin, tetracycline, trimethoprim/sulfamethoxazole.

Enterococcus: ampicillin, chloramphenicol, daptomycin,

erythromycin, gentamicin, kanamycin, lincomycin, linezolid, penicillin, quinupristin/dalfopristin, streptomycin, teicoplanin,

tetracycline, vancomycin and virginiamycin.

Campylobacter spp. : azithromycin, ciprofloxacin,

erythromycin, gentamicin, tetracycline, florfenicol, nalidixic acid, telithromycin, and clindamycin

Chicken Meat AMR study


Antibiotics used to treat pigsFirst line Second line Third line

Amoxicillin Amoxicillin-clavulanate Ceftiofur

Erythromycin Apramycin

Chlortetracycline Lincomycin

Oxytetracycline Trimethoprim

Sulphonamides Tiamulin

Kitasamycin Tulathromycin

Tilmicosin Spectinomycin

Tylosin

Penicillin

Florfenicol

Neomycin

Prohibited- Fluoroquinolones, Gentamicin, Chloramphenicol

Nitrofurans

Use first along

with alternative

treatment

approaches

When testing or

clinical results

show 1st line

ineffective

Last resort-other

options unavailable

& after

susceptibility

testing completed.

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Pig Industry Results

• Baseline data now established

• No colistin resistance

• No VRE

• Resistance seen to AB with a lower

importance rating

• Reflect reliance on first and second line AB

• Some other things to consider……….


E.coli & Salmonella• Similar levels of non-susceptibility to the critically important AB -

Levels could not be considered resistant

• 8.5% completely susceptible to all 14 AB (E coli)

• 14% completely susceptible to all 14 AB (Salmonella)

• No colistin resistance

• No ceftiofur resistance

• No extended-spectrum β-lactamase (ESBL) phenotype

• Florfenicol and gentamicin non-susceptibility was less than 10% & 2%,

• Low % of chloramphenicol resistance-where did that come from?

– Chloramphenicol use in livestock banned long ago (injectable)

– Resistance mechanisms probably co-located on a plasmid that

also is responsible for resistance of 1st line ABs

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Enterococci

• No vancomycin or linezolid resistance

• Resistance patterns reflect current reliance on macrolides and

tetracycline, (first line classes AMs with a lower importance rating)

• Further genetic evaluation to determine potential for public health

risk but highly likely to be distinct & of limited public health

significance

• No fluoroquinolone resistance was observed

• 12.7% completely susceptible to all 8 AB

• Resistance patterns reflect current reliance on first line classes

• Negligible public health significance based on the species identified

Campylobacter

• Report expected to be released by DAWR end 2017.

• Chicken industry implementing antimicrobial stewardship programme to compliment the current, and future AMR, studies

• For more information, please contact:

Kylie Hewson – [email protected]

Chicken Meat AMR study

mailto:[email protected]

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Next steps

• Great report card for public health but won’t rest

on our laurels

• AMR should be a focus for both human & animal

health considerations

• Further work

– Implementation of AMR Stewardship

– Automation of resistance surveillance

– Detection of resistance genes (assist with treatment

decisions)


Next - Industry Antimicrobial

Stewardship (Weese et al 2014)

• Responsibility– Vet, producer, stockpeople

• Reduction– Wherever possible

• Refinement– right drug, time, duration

• Replacement– Efficacy, safety, superiority

• Review– Includes surveillance

Industry

&

Farm by farm

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Questions?

Documents

Surveillance for antimicrobial resistance in enteric