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Antimicrobial resistance as an emerging food-borne infectious disease

Antimicrobial resistance as an emerging food-borne infectious disease



Food safety is also about acquired antimicrobial resistance in big farms, and its spread in the environment. Be a smart consumer, a smart producer, and a smart patient to contributing to get ...

Food safety is also about acquired antimicrobial resistance in big farms, and its spread in the environment. Be a smart consumer, a smart producer, and a smart patient to contributing to get antimicrobial resistance under control.



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    Antimicrobial resistance as an emerging food-borne infectious disease Antimicrobial resistance as an emerging food-borne infectious disease Presentation Transcript

    • Antimicrobial resistance as an emerging food-borne infectious disease How “superbugs” are grown in big farms and spread to humans 1
    • Pre-antibiotic era (1)  Traces of tetracycline in ancient Sudanese nubia skeletons (350-550CE)  Use of artemisin in Traditional Chinese Medicine  But no or vey limited selection pressure: the genes are present (genetic studies suggests that beta-lactamase gene is evolving for 100 millions years in some bacteria species (Fevre et al., 2005), but there is no differential value in terms of selection and evolution. 2
    • The rise of antibiotics (1)  Antibiotic era:  1899: Emmerich and Löw, preparation of a substance based on Pseudomonas aeruginosa extract, abandoned, but found later to contain antibiotic substances  Precursors of modern antibiotics: Ehrlich and Hata, 1910. Salvarsan and treatment of syphilis;  Fleming: discovery of Penicillin in 1929, but first medical use in 1940, and mass production in 1945; The end of infectious diseases was announced since the silver bullet was supposed to be discovered … 3
    • … and the fall of antibiotics: antimicrobial resistance  Definition (WHO): “resistance of a microorganism to an antimicrobial medicine to which it was originally sensitive.”  Exponential acceleration of AMR acquired under an unprecedented pressure selection due to a global misuse of antibiotics, including as growth promoter for rising farm animals, but also shrimps, fish …  Nowadays, one of the major public health threat:  (1) In the EU antimicrobial multiresistance, it is:  25,000 deaths/year,  1.5 billions € for extra healthcare cost and loss of productivity  (1) in the USA, 63,000 patients die every year from hospital-acquired bacterial infections  Limits treatment options, raises healthcare costs, and increases the number, severity, and duration of infections (2) 4
    • Antimicrobial resistance in Asia  Hospitals= « multiresistant bacteria factory »: (3) in HCMC tertiary hospital, 190 patients: 34.0% methicillin-resistant Staphylococcus aureus (MRSA), 61.3% extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (excluding Klebsiella pneumoniae), 53.4% Pseudomonas aeruginosa, 65.7% gentamicin-resistant K. pneumoniae, and 57.1 % amikacin-resistant Acinetobacter.  Food chain= very common mode of transmission of resistant bacteria (≠ transmission of resistance from bacteria to bacteria) from animals to humans. Ex. of Salmonella (typhoid fever pathogen):  (4), in Vietnam, 48.7% chicken carcass Salmonella-positive; 73.3% resistant to a least 1 antibiotic, and 17.7% multiresistant strains  (5) Multidrug resistant salmonella among humans in Vietnam: 50%, stable between 1993 and 2005; resistance to nalidixic acid increased from 4% to 97%;  (5): 381 Typhi strains from 8 Asian countries - Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam - collected in 2002 to 2004: multidrug resistance: from 16 to 37%; nalidixic acid resistance: 5 to 51%. The eight Asian countries involved in this study are home to 80% of the world's typhoid fever cases. 5
    • The study of Stuart B. Levy: ubiquitous, traveling antimicrobial resistance – findings (6) 1975-76: prospective study, introduction of antibiotic-laced food in chicken free of other any antibiotic use.  Chicken that didn’t eat this food and separated from the batch that received it were excreting tetracyclin-resistant E.coli after 48h, and multiresistant E. coli after 3 months  Farm families were also excreting E. coli resistant to ATB  People in the neighborhood excreted other bacteria – not E.coli – that were have acquired resistance to many other antibiotics 6
    • The study of Dr. Stuart B. Levy: ubiquitous, traveling antimicrobial resistance conclusions Lessons learnt from Dr. Levy’s studies:  a non therapeutic dose of antibiotics used as growth promoter can induce antimicrobial resistance among other animals not directly exposed to this ATB  A non therapeutic dose of antibiotics used as growth promoter can induce antimicrobial resistance to other antibiotics among non exposed farm animals  A non therapeutic dose of antibiotics in raising farm animals can induce antimicrobial resistance to non directly exposed human population around.  Further studies: antimicrobial resistance can be transmitted from animals to animals and to humans without the use of any antibiotics, in a farm setting  (multi)resistant bacteria can be found in almost all kind of environment, not only hospital settings. 7
    • The big picture of antimicrobial resistance 8
    • How come? …Transmission of resistance genes  Resistance is transmitted by another genetic material than chromosomal DNA: the plasmids:  Observation of 4-drugs resistant E. coli: 1 mutation in 10 millions doublings  1/(10*10^6)^4 =1/10^28 doublings  Another DNA support: plasmids  Plasmids carry the resistance genes, and other functionalities (antibacterial protein synthesis, virulence, …)  Horizontal transmission to any other kind of bacteria  Provide a selective advantage when under the pressure of antibiotics  Also used to clone genes in cells (genetically engineered human insulin) …  Other means of transfer of a gene resistance from bacteria to bacteria: transfer of free DNA, and viral transmission. 9
    • Mechanisms of transmission of resistance genes 10
    • Food safety …  goes far beyond the classic conception of « food-borne disease »;  is a necessary even though not sufficient mean of control of antimicrobial resistance from environmental origin;  is not only about tackling bacteria from food, but also looking upstream to sustainable and eco-responsible animal farming. 11
    • Solution#1: Be a smart consumer  Be curious and aware of the origin of your food:  Ask questions to the vendors, pay a visit to the producers;  Be an open-minded activist, push towards Ecoresponsibility and promote sustainable farming and agriculture in all the circles you belong to;  Buy local food: the closer to the producer, the more likely you are able to get a reliable information of the origin of the food and the method of production. 12
    • Solution#2: Be a smart producer or farmer Promote an appropriate use of antibiotic use in food animals: « To slow the pace of antibiotic resistance, emergence, and spread, the use of antimicrobials for animal growth promotion should be terminated. » (7) 13
    • Solution #3: be a smart patient Antibiotics are double-edged weapons:  Question your doctor for every antibiotics prescription;  Do not think that a common cold is treated with antibiotics;  An individual antibiotic treatment has an impact on all the communities you belong to (family, workplace, neighborhood, city, province, country, … Earth). 14
    • "Antibiotics are uniquely societal drugs because individual use affects others in the community and environment. Better stewardship, incentives, and establishment of a special regulatory category will improve how they are used, marketed, and developed through incentives to industry. » Stuart B. Levy, M.D. President of APUA, professor at Tufts University School of Medicine From the IOM 25th Anniversary Symposium (1996) and The Antibiotic Paradox (2002) Accessed on 24 February 2014 at http://www.tufts.edu/med/apua/index.shtml 15
    • References 1. A Brief History of the Antibiotic Era: Lessons Learned and Challenges for the Future. Aminov Rustam I. Front. Microbiol., 08 December 2010 | doi: 10.3389/fmicb.2010.00134 2. B. Marshall and S. Levy. “Food Animals and Antimicrobials: Impacts on Human Health”(2011) Clinical Microbiology Review 24,4:718-733 3. Effects of infection control measures on acquisition of five antimicrobial drug-resistant microorganisms in a tetanus intensive care unit in Vietnam. Constance Schultsz, Martinus C. J. Bootsma, Huynh T. Loan, et al. Intensive Care Med (2013) 39:661–671. DOI 10.1007/s00134012-2771-1 4. Quantification, serovars, and antibiotic resistance of salmonella isolated from retail raw chicken meat in Vietnam. Ta YT, Nguyen TT, To PB, Pham da X, Le HT, Thi GN, Alali WQ, Walls I, Doyle MP. J Food Prot. 2014 Jan;77(1):57-66. doi: 10.4315/0362-028X.JFP-13-221. 5. Antimicrobial drug resistance of Salmonella enterica serovar typhi in asia and molecular mechanism of reduced susceptibility to the fluoroquinolones. Chau TT et al., Antimicrob Agents Chemother. 2007 Dec;51(12):4315-23. Epub 2007 Oct 1. 6. The Antibiotic Paradox: How the Misuse of Antibiotics Destroys Their Curative Powers. Second edition. By Stuart B. Levy. 353 pp., illustrated. Cambridge, Mass., Perseus Publishing, 2002. $17.50. ISBN: 0-7382-0440-4 7. APUA: Alliance for the Prudent Use of Antibiotics. http://www.tufts.edu/med/apua/ @APUANews 16