FOOD SYSTEM AND ANTIMICROBIAL RESISTANCE
What is the prevalence of drug-resistant bacteria in our food supply today?
What does the label “antibiotic free” really mean? How should we handle the consumption of diseased food animals requiring antibiotic treatment?
Why is 95% of the antibiotics in the global salmon aquaculture industry used in Chile? Why do we not yet have a vaccine for salmonid rickettsial septicemia (SRS), which afflicts Chilean salmon aquaculture?
Antibiotics found to still be used in boosting animal growth
According to the World Organization for Animal Health (OIE), over a quarter of countries reporting for the period 2015-2017 admitted to using drugs in livestock farming in order to prevent infections and fatten them up. Among the 45 countries reporting for this time period, more than 26% stated that “last resort,” high priority, critically important drugs such as colistin were being used for growth promotion even with the banning of such antibiotics in the European Union since 2006 and the United States since 2017. Of note, the countries still using antibiotics during the reporting period spanned across the Americas (18 countries), Africa (10 countries), and Asia + Oceania (14). As a result, the WHO’s director general, Tedros Adhanom Ghebreyesus, admitted to Reuters that the report shows a “long way to go,” but the number of countries using antibiotics in livestock has decreased from 60 to 45 countries since the last round of data collection before 2014. However, there is still much work to be done on the local, regional, national, and international level. As Matt Stone, the OIE’s deputy director general explains, “we have made very explicit and clear recommendations that we’d like to see an immediate end to the use of this [colistin] class of antibiotics. This is as clear as we can be.”
Source: World Health Organization
Antibiotic resistance spreads faster than previously thought in livestock
By feeding antibiotics to fish and studying their gut bacteria, researchers have found that antibiotics are spread through mechanisms more varied than previously hypothesized. In a study published in Microbiome, pacu fish were fed the antibiotic florfenicol for 34 days, and then their digestive tract was examined for changes in gut bacteria. While it was to be expected that this antibiotic uptake would increase genes responsible for resistance to the antibiotic florfenicol, researchers were surprised by the different mechanisms in which resistance was exchanged, as well as the speed by which resistance was found. The evidence suggested that bacteria present in the fish’s gut exchanged resistance through viruses, as well as transposons, without the exclusive involvement of plasmids, as previously thought. Especially relevant for the aquaculture industry, this study could be useful in evaluating the use of antibiotics in aquaculture, especially for preventative measures. Indeed, in the last 10 years alone, more than 5,500 tons of the antibiotic florfenicol has been used in the Chilean salmon farming industry.
US PIRG releases food safety report
With the number of unsafe food recalls increasing 10% from 2013 to 2017, one report released by the US PIRG Education Fund aimed to examine the drivers behind this increase in unsafe food recalls, in addition to 70% increases in chicken recalls and an 83% increase in “most hazardous meat and poultry recalls.” By examining a variety of drivers behind food recalls, as well as case studies, the report concluded that gaps in public health protections, as well as enforcement and inspections are the main culprit in the increase in unsafe food recalls. As a result, the study recommends a multiple policy solutions, including 1) food production and test, 2) inspection and monitoring, 3) traceability, and 4) recall effectiveness.
Source: US PIRG
Anthony So speaks at the CFR symposium on trade, agriculture, and antimicrobial resistance
Speaking at the U.S. Council on Foreign Relations on April 16th, Professor Anthony So, Director of ReAct’s Strategic Policy Program, addressed the topic of “Trade, Agriculture and Antimicrobial Resistance” at a Global Health Symposium on “Is Globalizing Still Good for Health?” Following opening remarks by Tom Bollyky, Senior Fellow at the Council, Dr. So described how the $1.1 trillion in agricultural trade that connected the globe and also ensured greater food security could also be “a superhighway for distributing the next superbug.” Globalizing the response to these drug-resistant pathogens that so readily cross borders will require investment. The World Bank’s 2017 report, Drug-Resistant Infections: A Threat to Our Economic Future, suggests that the economic consequences of AMR, if unchecked, will fall disproportionately on low- and middle-income countries, and the gains from investing in AMR, disproportionately will flow to upper-middle and high-income countries. The challenge of antimicrobial use in food animal production is immense, but Dr. So argued that the patterns of trade flow can help prioritize where this work must begin. By OECD projections, just five countries accounted for over half of the world’s use of antimicrobial in food animal production in 2010—the United, States, China, Brazil, India and Germany—and the export of food animal products from these countries also is rather concentrated. He also highlighted the important gains brought about by consumer campaigns targeting public-facing restaurant chains that procure such food animal products as well as the Chain Reaction Report, providing a scorecard on the concessions made by these companies. Kathy Talkington of Pew Trusts and Air Hoe Lim from the World Trade Organization’s Trade and Environment Directorate rounded out the panel.
Source: Council on Foreign Relations
European Food Safety Authority shows link between AMR in animals and humans
The European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) released their summary report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals, and food, in which data submitted by 28 EU member states were jointly analyzed for trends in antimicrobial resistance. The report, which references 2017 data, found that antimicrobials used to treat diseases that can be transmitted between animals and humans, such as Campylobacter and Salmonella, are becoming less and less effective. More specifically, resistance to fluoroquinolones (antibiotics too commonly used to treat respiratory infections) was found to be highly prevalent, and Salmonella, displaying multi-drug resistance in both humans and animals. Moreover, the report found that resistance levels to fluoroquinolones among Campylobacterbacteria, a common cause of foodborne illness, rendered this class of antimicrobials ineffective for treatment of severe Campylobacter infections. However, the report also found that combined resistance to critically important antimicrobials in both Salmonella and Campylobacter from both humans and animals was low, indicating that there is a chance comprehensive action plans could be implemented immediately to stem the tide of antimicrobial resistance. The report finds that when Member States implements stringent policies surrounding antibiotic use in animals, antimicrobial resistance decreases in animals. The report shows that infections directly acquired from animals are increasing and becoming more antibiotic resistant, demanding urgent change.
Source: European Food Safety Authority
More antibiotics found to be used in the chilean salmon industry than any other meat industry
According to an Oceana report, salmon farmers in Chile are raising one ton of fish with up to 950 grams of antibiotics, implying that Chile’s salmon farmers might be using more antibiotics per ton of meat than any other meat industry in the world. This compares to Norway’s salmon industry, which uses only 0.17 grams per ton of salmon, and the international pork industry which uses an average of 172 grams per ton. Serving as the world’s second-largest producer of farmed salmon, Chile’s salmon farms perpetuate the selection of genetic mutations that protect bacteria from antibiotics. As these antibiotic-resistant bacteria multiply, they are extremely likely to both transfer across geographic regions, both within Chilean farms and internationally, to different populations, as well as be ingested in the form of raw fish by consumers.
Responding to the heavy use of antibiotics in Chilean salmon aquaculture, distributors such as Whole Foods and Target have either stocked farmed salmon from European countries only, or have not sold farmed salmon of any kind. Yet other retailers, such as Costco, have significant reduced sales of Chilean salmon, but with the cheapness of Chilean salmon combined with inadequate US regulations on documentation of produce origin, these supplies can be hard to remove. However, as advocacy groups continue to publicize the issue and spread awareness, changes in consumer demand could help drive change.
Bacitracin use found to make bacteria less susceptible to colistin
The MCR-1 gene, which is responsible for colistin resistance, has been found to confer cross-resistance to bacitracin, an antibiotic commonly used in animal feed throughout the animal industry. By creating E. coli strains with and without the presence of a functional MCR-1 gene, researchers used bacitracin for susceptibility tests, and found that the minimum inhibitory concentration (MIC) for both colistin and bacitracin were increased (by 4-8 fold and 8 fold, respectively) in the strains with functional MCR-1 genes. Further analysis of results showed that in the presence of bacitracin, MCR-1 gave an advantage to various E. coli strains. These findings are alarming, as the results show that the imprudent use of bacitracin in feed may increase MCR-1 positive E. coli strains, in turn exacerbating both bacitracin resistance and plasmid-mediated colistin resistance, which serve as “last resort” drugs used to treat multidrug-resistant infections in humans. While there are limits to the veterinary use of colistin for growth promotion in animals take the spotlight internationally, this research suggests that colistin resistance could arise even without direct exposure to the drug.