Martin Chénier, Ph.D. Microbiology. Antibiotics in Animal Production: Resistance and Alternative Solutions

Transcription

1 Faculty of Agricultural and Environmental Sciences Department of Food Science, Department of Animal Science Martin Chénier, Ph.D. Microbiology Antibiotics in Animal Production: Resistance and Alternative Solutions February 23 rd, 2012 Food Safety Forum Food and Consumer Products Canada, Toronto, ON

2 Antibiotic Resistance and Food Safety Witte 1998 Science 2

3 Meat Safety What is the impact of antibiotics use in animal production on antibiotic resistance at the farm? Does antibiotic resistance persist over time at the farm? Can farm effluents be treated in order to mitigate antibiotic resistance? What alternative solutions may be considered for decreasing antibiotic use and resistance at the farm? 3

4 Antibiotics in Swine Production Canadian Food Inspection Agency Compendium of Medicating Ingredient Brochures CMIB Nutritional applications (dabated) Stimulation of growth rates Improvement of feed conversion efficiency Therapeutic applications (required) Treatment of respiratory, digestive, skin diseases Prophylaxis 4

5 CIPARS 2007 Annual Report Chlortetracycline hydrochloride and tylosin phosphate: Wide diversity of applications Used in abundance 5

6 Experimental Approach Horizontal transfer Pathogens Commensals Anaerobes Aerobes Reservoir of resistance 6

7 Figure 1a. Percentage of chlortetracycline-resistant anaerobic bacteria in each treatment group and production phase. = control group, =TYL, =CTC.

8 Figure 1b. Percentage of tylosin-resistant anaerobic bacteria in each treatment group and production phase. = control group, =TYL, =CTC.

9 Meat Safety Does antibiotic resistance persist over time at the farm? Since January 2007 Ban of antibiotic use for nutrition and prophylaxis Objective To determine the occurrence of antibiotic resistance 2.5 years after the ban 9

10 Table 1. Resistance genes. tet(abcdeklmosy) erm(abc) Phase Pig # Suckling Weanling tet(los) Growing tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) Finishing tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) tet(o) 10

11 Figure 2. Abundance of tet(o) among bacterial populations in males and females during suckling (S), weanling (W), growing (G), and finishing (F). 11

12 Antibiotic Resistance and Food Safety Witte 1998 Science X 12

13 Aérobie Anaérobie Avant Après Avant Après M Tot Tet R Tyl R Tot Tet R Tyl R M Tot Tet R Tyl R Tot Tet R Tyl R A D F H B C E G Figure 4. Bacterial biodiversity (DGGE 37 o C). 13

14 Swine origin 93,5% similarity with B > 97% similarity with B Figure 5. Phylogeny of clones from Tyl R aerobic populations at 37 o C. Bootstrap values (expressed as percentage of 1,000 replications) greater than 50% are shown at branch points. Bar = 0.05 nucleotide substitution per position. 14

15 Alternatives to Antibiotics Canadian Food Inspection Agency Compendium of Medicating Ingredient Brochures CMIB Nutritional applications: dabated alternatives? Stimulation of growth rates Improvement of feed conversion efficiency Therapeutic applications (required) Treatment of respiratory, digestive, skin diseases Prophylaxis 15

16 Meat Safety What alternative solutions may be considered for decreasing antibiotic use and resistance at the farm? Natural and sustainable alternative solutions to antibiotics Organic acids Prebiotics and probiotics Essential oils (plant extracts) Clays 16

17 Nutrients: proteins, carbohydrates, lipids, vitamins, minerals Additives: antibiotics, alternative solutions Diet Animal performance (DWG, FCE) Meat safety and quality Infectious diseases Health Microflora Host Pathogens, Model for medical research: opportunists, Non-infectious diseases commensals, Fecal transplant 17 antibiotic-resistant

18 Macdonald Campus Farm Gestation 1 room, 48 pens = 48 boars / sows Farrowing and Suckling 2 rooms, 7 pens / room = 14 sows Weanling 2 rooms, 16 pens / room, 6 pigs / pen = 192 pigs Growing and Finishing 2 rooms, 16 pens / room, 6 pigs / pen = 192 pigs 18

19 Funding Team Ms. Sepideh Pakpour, M.Sc. Dr. Melissa Buzinhani Mr. Devin Holman, Ph.D. Mr. Philippe LeBel, M.Sc. Collaborators University of Montreal Faculty of Veterinary Medicine Dr. Philippe Fravalo, Dr. Ann Letellier McGill University Dr. Ken Dewar (Faculty of Medicine) Dr. Xin Zhao (Faculty of Agricultural and Environmental Sciences) Dr. Vilceu Bordignon, DVM (Faculty of Agricultural and Environmental Sciences) INRS Institut Armand-Frappier: Dr. Pierre Juteau 19

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22 Modes of action of antibiotics. Figure Brock 22

23 Tetracyclines: Bacteriostatic Wide spectrum Gram + and Gram - Macrolides: Bacteriostatic Narrow spectrum Gram + (Gram -) Figure 10.4 Bauman 23

24 Horizontal gene transfer between bacteria. Furuya and Lowy 2006 Nat Rev Microbiol 4:36-45 Figure 2 24

25 Confers resistance Captures and links multiple resistance genes Physically moves or replicates generally within a chromosome or plasmid, or promoter activity of ORF orit = mobilization and ori = replication Self-replicating, can disseminate among bacteria = physical transfer Building blocks in the acquisition of HGT-mediated antibiotic resistance. Martinez et al 2006 FEMS Microbiol Rev 33:44-65 Figure 4 25

26 Mechanisms of resistance to antibiotics. Tortora Figure

27 Acquired resistance genes to tetracyclines and macrolides. ( Antibiotics Resistance mechanism Number of genes Ribosomal protection 11 Tetracyclines Efflux 27 Enzymatic inactivation 3 Total 41 Number of genera 70 Gram +, 12 anaerobes 40 Gram -, 7 anaerobes Macrolides Methylation of the ribosome 33 Efflux 16 Enzymatic inactivation Tens of Gram + and Gram - 15 anaerobes 27

28 (2001) Microbiol Mol Biol Rev 65: Tetracyclines 28

29 Macrolides Rings with 14, 15 or 16 atoms 16 atoms 29

30 Aerobic Thermophilic Sequencing Batch Reactor