First it showed up in China, then Denmark and now it has reared its ugly head in the United Kingdom. Bacteria resistant to all forms of antibiotics are making their way around the globe.
Chinese health officials announced in late November that bacteria containing the MCR-1 gene had been discovered in livestock as well as 1,322 hospitalized patients. Then, the same pathogen was discovered in Denmark when a patient in one of the nation’s hospitals was diagnosed with an untreatable form of salmonella.
The superbugs were also detected in Africa, and are believed to have traveled to Laos and Malaysia. Experts say they likely got to Britain via global travel and food imports.
The bacteria have since made their way into England on 3 farms and in samples of human infections.
The MCR-1 gene is “mobile DNA” that can be easily copied and transferred between different bacteria, making it easy for it to spread and diversify between bacterial populations, Scientific American explained in a December 19 article.
The gene makes infections resistant to all polymyxin antibiotics, including colistic, which are the last line of defense when all other antibiotics have failed. [1]
The fear is that MCR-1 could transfer to other bacteria and turn them into superbugs, too.
Experts have been warning that untreatable infections could create an “antibiotic apocalypse” that would plunge medicine back into the dark ages. Scientists said humanity was on the brink of just such an era when the drug-resistant bacteria were discovered in China, not knowing how quickly it would cross oceans and infect more animals and people.
Scientists in the U.K. say that the danger to humans is low, for now, but they also thought they had 3 more years before colistin-resistance would spread from China to England, not just a single month.
Professor Alan Johnson, from Public Health England, said:
“Our assessment is that the public health risk posed by this gene is currently considered very low, but is subject to ongoing review as more information becomes available.
The organisms identified can be killed by cooking your food properly and all the bacteria we identified with this gene were responsive to other antibiotics, called carbapenems.
We will monitor this closely, and will provide any further public advice as needed.” [2]
Out of 24,000 bacterial samples kept on record from 2012 to 2015 by Public Health England, 15 of them tested positive for colistin-resistant bacteria, including samples of salmonella and E. coli. The E. coli bacteria were also found to be resistant to cephalosporin antibiotics. The bugs were also discovered on 3 pig farms by the Animals and Plant Health Agency.
Colistin is heavily overused in livestock, namely pigs and chickens, where it is given to animals to promote growth and prevent them from getting sick. Scientists believe the MCR-1 gene has spread from farm animals to humans because it is used far more frequently in veterinary medicine than in human medicine.
Cóilín Nunan, Scientific Adviser to the Alliance to Save Our Antibiotics, 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.”
Fortunately, colistin isn’t given to livestock in the United States, but about 80% of antibiotics sold in the U.S. go to livestock farms, and 60% of those drugs are considered crucial to human medicine. We are far from safe; the MCR-1 gene could just as easily transfer to penicillin.
Antibiotic resistance kills some 700,000 people globally every year, and that number is expected to rise to 10 million by 2050. [3]
Sources:
[1] Scientific American
[2] BBC News
[3] Mother Jones