Surveillance for antimicrobial resistance in enteric bacteria in Australian pigs and chickens Dr Pat Mitchell R & I Manager Production Stewardship APL CDC Conference, Melbourne June 2017 Dr Kylie Hewson Assistant Executive Director ACMF www.australianpork.com.au CDC Conference June June 2017 2017 Breeding herd size ~275,000 sows Annual slaughter ~ 5.15 M Kg Produced China ~ 392,830,000 50M Kg Exported ~ 36,972,000 (9.4%) USA ~ 6M Iowa ~1 million, 7 Pig Specific Export Plants Approx 15 others Pig producers ~ 1,400 North Carolina 400 producers ~ 840,000 ~90% of production Production systems: Canada~1.3M 1,000 producers ~ 10% of production Conventional housed ~ 90% Denmark~1.03M Pork consumption: ~ 26kg Outdoor housed ~10% Fresh ~ 10kg Processed ~ 16kg Imported processed ~70% 1
Location of Chicken Meat Production Key facts about the Australian chicken meat industry Chicken produced 1,154,000 tonnes Chicken meat produced pa 623.3 million Number of chickens slaughtered pa 46.2 kg Per capita consumption Chicken Meat Produced ( 000 tones) Slaughterings (million birds) 7 companies = >90% production 21 processing plants 34,500 tonnes Volume of chicken meat exports pa 2
O Neill 2016. 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. 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 3
Antimicrobial surveillance project 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. Isolates Pigs E. Coli 200 206 Enterococcus 146 205 Salmonella 84 53 Campylobacter 171 204 TOTAL 601 668 Chicken 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 nonsusceptible which comes from the CLSI intermediate break point. 4
Chicken Meat AMR study 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 Prohibited- Antibiotics used to treat pigs First line Second line Third line Amoxicillin Amoxicillin-clavulanate Ceftiofur Erythromycin Chlortetracycline Oxytetracycline Sulphonamides Kitasamycin Tilmicosin Tylosin Penicillin Florfenicol Neomycin Apramycin Lincomycin Use first along with Trimethoprim alternative treatment Tiamulin approaches Tulathromycin Spectinomycin When testing or clinical results show 1 st line ineffective Last resort-other options unavailable & after susceptibility testing completed. Fluoroquinolones, Gentamicin, Chloramphenicol Nitrofurans 5
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 1 st line ABs 6
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 Campylobacter 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 Chicken Meat AMR study 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 kylie.hewson@chicken.org.au 7
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 Industry Reduction Vet, producer, stockpeople Wherever possible Refinement & right drug, time, duration Replacement Farm by farm Review Efficacy, safety, superiority Includes surveillance 8
Questions? 9