Scientists have expressed shock at the speed at which resistance to powerful antibiotics spreads from animals to humans, as new research has shown how genetic mutations in pathogens likely spread from a pig farm in China to affect human and animal species across the world in the space of just a few years.

The antibiotic Colistin is known as a medicine of “last resort,” used to save people’s lives when all other drugs have failed. Lead researcher Professor Francois Balloux, director of the Genetics Institute at University College London says it has become an important last line of defense as other antibiotics have become less effective.

“It was used a bit in the clinic. And then there were some worries about toxicity and side-effects. And it was mostly used in agriculture then, in pigs and a bit in chickens. But recently, as we are running out of drugs, people actually have become a bit more interested in using it, and it has been used quite extensively recently over the last five to 10 years in the clinic,” says Balloux.

Now even Colistin is losing its potency against so-called “superbugs”.

Fast mutation

Deadly pathogens like E. Coli or salmonella can mutate and develop resistance to antibiotics. Balloux’s research identifies the speed at which the mutant gene that gives resistance to Colistin emerged in the mid-2000s.

“It was a single mergence, it happened only once. And it jumped very, very likely from pigs, probably in China, and it spread extremely rapidly throughout the world. And it also spread in all sorts of different species, and affects humans. So now we find it in in many of the most important pathogens we face in hospitals. And it is absolutely everywhere,” Balloux told VOA.

The resistance has even been found in pathogens in the seawater on Brazilian beaches. Balloux notes his study focused on just one resistant gene, but many pathogens are developing other forms of resistance.

Britain’s chief medical officer warned recently that anti-microbial resistance could lead to the “end of modern medicine.”

“Think about common operations, caesarean sections, replacement hips. Those would become much more risky if we did not have effective antibiotics. Superbugs kill and they’re on the rise,” Professor Sally Davies told delegates at an October conference on anti-microbial resistance in Germany.

Scientists are working on “boosting” existing drugs like Colistin to give them added power against resistant pathogens.

Longer-term, researchers say more investment is needed in developing new drugs, along with a rethink of the way antibiotics are used in agriculture and in the clinic.
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