03
Oct
Study Raises Global Red Flag Regarding Antimicrobial Resistance in Animal Food Production
Fig. 3 Geographic distribution of antimicrobial resistance in LIMCs. (A) P50, the proportion of antimicrobial compounds with resistance higher than 50%.
(Beyond Pesticides, October 3, 2019) A study in the journal Science focuses on the global threat of antimicrobial resistance (AMR) due to overuse of animal antibiotics in food produced for low- and middle-income countries. Authors conclude, “the portfolio of antimicrobials used to raise animals for food is rapidly getting depleted, with important consequences for animal health, farmers’ livelihoods, and potentially for human health.” Highest resistance rates were observed for the most commonly used antimicrobials in animal production: tetracyclines, sulfonamides, and penicillins.
Researchers used data from 901 point prevalence surveys – a data collection tool used to identify number of infections – from low- and middle-income countries that reported antimicrobial resistance rates of common infectious microbes (e.g. E. coli, Salmonella spp.) found in animals raised for food production. Using geospatial models they produced global maps of antimicrobial resistance.
The important findings include:
- From 2000-2018, the proportion of antimicrobial compounds with resistance higher than 50% (P50) increased from 0.15 to 0.41 in chickens and from 0.13 to 0.34 in pigs and plateaued between 0.12 and 0.23 in cattle.
- Global maps of antimicrobial resistance show hotspots of resistance in northeastern India, northeastern China, northern Pakistan, Iran, eastern Turkey, the south coast of Brazil, Egypt, the Red River delta in Vietnam, and the areas surrounding Mexico City and Johannesburg.
- Areas where resistance is just starting to emerge are Kenya, morocco, Uruguay, southern Brazil, central India, and southern China.
Meat consumption has increased in low- and middle-income countries due to global expansion of intensive animal production systems, often taking the form of concentrated animal feeding operations (CAFOS). As animals are clustered together, risk of disease increases and therefore antimicrobials are often used preventively.
The World Health Organization (WHO) told its member states in 2017 to reduce veterinary antimicrobial use due to the potential threat it poses to human health. Antimicrobial resistance is becoming a more common global issue with estimates of 700,000 to a million deaths per year.
Beyond Pesticides wrote extensively on the topic of antibiotic resistance – a subset of antimicrobial resistance – and its relationship to food production in 2016. Antibiotic use is prohibited in all organic production. Though organic standards require sick animals to be treated, animal products from that treated animal cannot be sold as organic.
As stated in Pesticides and You, “It may not be widely appreciated that use of antibiotics on fruit trees can contribute to resistance to the antibiotic in human pathogens. The human pathogenic organisms themselves do not need to be sprayed by the antibiotic because movement of genes in bacteria is not solely ‘vertical,’ that is from parent to progeny—but can be ‘horizontal’— from one bacterial species to another. So, a pool of resistant soil bacteria or commensal gut bacteria can provide the genetic material for resistance in human pathogens.”
The basic mechanism is as follows. If bacteria on the plants and in the soil are sprayed with an antibiotic, those with genes for resistance to the chemical increase compared to those susceptible to the antibiotic. Resistance genes exist for both streptomycin and tetracycline, and spraying with these chemicals increases the frequency of resistant genotypes by killing those susceptible to the antibiotic and leaving the others. Those genes may be taken up by other bacteria through a number of mechanisms, collectively known as ‘horizontal gene transfer.’”
The same principle of horizontal gene transfer applies to antimicrobial resistance created during animal production. The authors of this new study suggest that countries with high AMR, such as China, take immediate steps to restrict animal use of antimicrobials critical to human medicine. They suggest high-income countries support the transition to sustainable animal production through, for example, “a global fund to subsidize improvements in farm-level biosafety and biosecurity.” In countries where AMR is low or just starting to emerge, they point out, it is possible to intervene and point farmers in a different direction. Beyond Pesticides advocates, for the sake of human safety and environmental sustainability, that direction should be organic.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Science
