1 February 2018 (Bangkok) – To fight the growing global threat of antibiotic-resistant bacteria, food labels around the world should include an ‘antibiotic footprint’ section that clearly shows the type and amount of antibiotics used to produce that food, say scientists in a study released today in the Bulletin of the World Health Organization (WHO).
The study, a collaboration between researchers at Mahidol University and the Ministry of Public Health, Thailand, and the University of Oxford in the UK, looked at the amount of antibiotics given to chickens over their lifetime to roughly estimate the total amount of antibiotics used per year in the production of chicken meat countrywide.
It found that 5 of the world’s important antimicrobials, including colistin, currently considered the last defence against multidrug-resistant bacteria, were routinely used as prophylaxis – to prevent disease – in all chickens raised in a small sample of chicken farms surveyed in Thailand (see Table 1). Although antibiotics were halted 10 days before harvesting to eliminate them in the meat reaching consumers, the antibiotics used were likely excreted un-metabolized and entered sewage systems and water sources, fostering the emergence of resistance in bacteria.
“Consumers believe, often incorrectly, that meat labelled ‘antibiotic-free’ comes from animals raised without the use of antibiotics. Accurate food labelling clearly displaying the ‘antibiotic footprint’ – the total amount of antibiotics used to produce that portion of food, possibly comparing it with global targets – would empower consumers, and thereby encourage a reduction in antibiotic use globally and lead to a reduction in deaths caused by drug-resistant infections,” said study senior author Associate Professor Direk Limmathurotsakul, Head of Microbiology at the Mahidol Oxford Tropical Medicine Research Unit (MORU), in Bangkok.
Reducing the misuse and overuse of antibiotics by industry and consumers is critical to any global attempts to reduce environmental contamination with antibiotics and prevent the emergence and spread of antibiotic-resistant bacteria, the scientists note.
“Our overuse of antibiotics means we now face infections that we simply cannot treat as they are resistant to all known antimicrobial drugs. Bacteria resistant to both of the two ‘last resort’ antibiotics, the cabapenems and colistin used to treat common highly drug resistant hospital superbugs – multidrug resistant Enterobacteraciae such as E. coli, Klebsiella and Acinetobacter that cause life-threatening pneumonias and bloodstream infections – are widespread. We estimated in 2016 that in Thailand alone an additional 19,000 deaths from infection each year are attributable to antimicrobial resistance,” says study co-author and MORU Director Prof Nicholas PJ Day.
Noting their study limitations, the scientists estimated that roughly 161 metric tonnes (MT) of antibiotics were annually used to produce chickens alone in Thailand, indicative of a larger global problem.
The European Medical Agency found a wide range of antibiotics usage in food-producing animals in the EU in 2015, with the Netherlands using 213.7 MT of antibiotics, the United Kingdom 394.9 MT and Spain 3,027.8 MT. The US Food and Drug Administration (FDA) has approved for use in animals amoxicillin, colistin, doxycycline, oxytetracycline and timmicosin – all five of the important antimicrobials the study found being used in Thailand.
“We don’t know how many tonnes of antibiotics are used in raising Thai food-producing animals each year – our calculation could be an underestimate or an overestimate. Our work clearly points out that such information is urgently needed globally to promote the appropriate use of antibiotics in animal health around the world,” said study contributor Dr Soawapak Hinjoy, Bureau of Epidemiology, Ministry of Public Health, Thailand.
Dr Tim Jinks, Wellcome's Head of the Drug-Resistant Infections said: "To effectively tackle the urgent global health problem of superbugs we need to build understanding of antibiotic use across the world – in human and animal health – and the impact of inappropriate use. Studies like this are vital to building this picture of when and how antibiotics are being used, in what quantities and how this impacts drug resistance in dangerous bacteria. Wellcome is committed to utilising surveillance globally to inform both public behaviour and drive policy change needed to reduce inappropriate antibiotic use."
Antibiotic use in farming chicken meat: a survey of eight farms in Thailand. Wongsuvan G, Wuthiekanun V, Hinjoy S, Day NPJ, Limmathurotsakul D. Bulletin of the World Health Organization; Article ID: BLT.17.195834 doi:http://dx.doi.org/10.2471/BLT.17.195834
WHO Guidelines on Use of Medically Important Antimicrobials in Food-Producing Animals (Full Report) http://apps.who.int/iris/bitstream/10665/258970/1/9789241550130-eng.pdf?ua=1
WHO Guidelines on Use of Medically Important Antimicrobials in Food-Producing Animals (Executive Summary). http://apps.who.int/iris/bitstream/10665/259240/1/WHO-NMH-FOS-FZD-17.4-eng.pdf?ua=1
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