Antibiotic Resistance: The Medical Commons Being Consumed by Industrial Agriculture

What it is

Antibiotic resistance — the evolution of bacterial strains that no longer respond to antibiotic treatment — is one of the most serious emerging threats to global public health. Animal agriculture, through its routine sub-therapeutic use of antibiotics, is a major driver of this crisis. This section cross-references the antibiotic material in Part I with specific focus on the public health and ecological dimensions.

The numbers: In 2015, approximately 131,000 metric tons of antibiotics were used globally in food animal production, according to estimates by Princeton University researchers. This is projected to grow significantly by 2030 as middle-income countries expand their industrial livestock sectors. In the United States, FDA sales data has consistently shown that 70% to 80% of all antibiotics sold domestically are for agricultural use — the vast majority in feed and water for livestock, not for treating sick animals but for growth promotion and disease prevention in confinement conditions. This includes antibiotics that are critically important to human medicine, including fluoroquinolones (a class that includes ciprofloxacin, used to treat drug-resistant Salmonella and Campylobacter) and cephalosporins.

The mechanism of resistance development is straightforward evolutionary biology. Any use of antibiotics — at therapeutic or sub-therapeutic doses — exerts selective pressure on bacterial populations, killing susceptible bacteria and allowing resistant variants to survive and reproduce. Sub-therapeutic use, by maintaining constant low-level antibiotic pressure over extended periods across millions of animals, provides near-optimal conditions for resistance selection. The resistant bacteria produced in livestock facilities — on the animals' skin and in their guts — can spread through multiple pathways: through meat and other food products, through farm workers who carry bacteria from facility to community, through flies and other vectors from manure lagoons, through agricultural runoff into water, and through the application of antibiotic-laden manure to cropland.

The Centers for Disease Control (CDC) estimates that antibiotic-resistant infections cause approximately 35,000 deaths annually in the United States alone and cost the health care system approximately $55 billion annually. The WHO has declared antimicrobial resistance one of the ten greatest threats to global health. The most alarming developments include: the spread of carbapenem-resistant Enterobacteriaceae (CRE) — bacteria resistant to the antibiotics of last resort — in clinical settings; the emergence of MRSA (methicillin-resistant Staphylococcus aureus) strains linked to livestock production; and the emergence of colistin resistance in livestock in China following widespread use of the antibiotic as a growth promoter (China subsequently banned colistin for growth promotion in 2017).

Reference notes

Cross-link to: Antibiotic-Free Meat Certification, The EU Antibiotic Farming Ban, Organic Certification and Antibiotics, Food Safety and Drug Resistance.

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