Government scientists have found a gene, which makes bacteria resistant to an antibiotic used as a last resort in human medicine, in E. coli from pigs and from human E. coli infections in England and Wales.
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The emergence of resistance to the antibiotic, colistin, is considered to be a major step towards completely untreatable infections.
The colistin resistance gene, called mcr-1, was first found last month in China in pigs, retail meat and human infections.
Colistin is frequently used for mass medication of intensively farmed pigs and poultry, and scientists believe that the resistance gene has spread from farm animals to humans because the antibiotic is used much more widely in veterinary medicine than it is in human medicine.
A Freedom of Information request submitted by the Alliance to Save Our Antibiotics has established that 837kg of colistin were sold for use in British farm animals in 2014, whereas just 300kg are used per year in human medicine.
In Europe as a whole, the amount used in farm animals (545 tonnes) is more than 500 times higher than the amount used in humans (about 1 tonne), with use in farm animals in Spain (177 tonnes), Italy (133 tonnes), Germany (124 tonnes) and France (50 tonnes) being particularly high.
CóilÃn Nunan, Scientific Adviser to the Alliance, said “Despite scientists saying that resistance to this last-resort antibiotic is likely to be spreading from farm animals to humans, it still remains completely legal in the UK and in most EU countries to routinely feed colistin to large groups of intensively farmed animals, even when no disease has been diagnosed in any of the animals.
“We need the government, the European Commission and regulatory bodies like the Veterinary Medicines Directorate to respond urgently. The routine preventative use in farming of colistin, and all antibiotics important in human medicine, needs to be banned immediately.â€
Since the Chinese discovery of mcr-1 in November, scientists around the world have been re-examining their collections of bacteria from farm animals and humans for the gene.
British government scientists found the mcr-1 gene in E. coli from two separate pig farms, in one stored E. coli from a pig, and in three E. coli from two separate patients. The E. coli from the human patients were also resistant to the critically important cephalosporin antibiotics.
The colistin gene was also found in ten human salmonella infections and in salmonella from a single imported sample of poultry meat. The earliest British positive sample was a salmonella from 2012.
In the past few weeks, the resistance gene has also been found in Denmark, France, the Netherlands, Portugal and in several Asian and African countries . ■