Bacteria resistant to ‘last-line’ antibiotics discovered in Chinese factory farms

June 8, 2016

Recently it has been announced that researchers have discovered a new gene in E coli bacteria that causes antibiotic resistance. This gene, dubbed MCR-1, promotes resistance to our most potent ‘last-line’ polymixin antibiotics, including colistin. These new strains of colistin resistant bacteria were discovered during a routine surveillance project on antimicrobial resistance in E coli from food animals in China. Resistance was discovered in a fifth of pigs tested, 15% of raw meat samples and 16 patients (BBC).

It is thought this resistance has emerged in China, in particular, due to the country’s widespread overuse of antibiotics in the factory farming industry. Agriculture accounts for roughly half of all antibiotic use in China and pound for pound, livestock in China are fed around three times more antibiotics than those in the U.S (Bloomberg). This is the result of China’s dramatic intensification of agriculture to meet ever increasing demand for meat and dairy products. In order to supply this demand, China have adopted the factory farming model. This has provided the perfect breeding ground for potentially deadly antibiotic resistant bacteria, a large proportion of pork being raised in large industrial-scale sheds that are usually very cramped and unsanitary.

This poses a significant threat to human health. Antimicrobial resistance currently accounts for roughly 700,000 deaths per year globally and this figure is expected to rise to 10 million deaths per year by 2050, assuming we still have effective drugs (Independent). Dr. Patrick Harris, a physician and microbiologist with the University of Queensland, has commented that if colistin resistance goes global the effects would be huge; for example, mortality rates for blood infections would rise from 50% to the pre-penicillin rate of 80% thus meaning many modern surgeries such as transplants would no longer be viable (VICE).

It is common practice to feed livestock antibiotics, including colistin, globally. In the U.S 80% of all antibiotics sold are for use on livestock and poultry (NRDC) and this use is largely to prevent rather than treat disease. Colistin resistance is expected to spread with evidence suggesting it may have already done so in Laos and Malaysia (Bloomberg). Professor Timothy Walsh of the University of Cardiff who collaborated on the study in China has commented that the global spread of MCR-1 ‘is a case of when not if’ and that this combined with the gene inevitably aligning itself with other antibiotic resistant genes will likely signify the start of the ‘post-antibiotic era’ (BBC), referred to by others as the ‘post-antibiotic apocalypse’ (Bloomberg).

Estimates suggest the cost of dealing with such a crisis would be exorbitant; it could potentially result in a global GDP reduction of between 2 – 3.5% and cost up to $100 trillion USD (Independent) to resolve. In response to this report, 20 health and medical experts have called on the British government and the European Commission to end the routine use of preventative antibiotics on healthy animals (Farmers Weekly). Despite this and persistent warnings from various experts that antimicrobial resistance would become a global threat, we are seemingly on the cusp of the post antibiotic era.