A bacteria that resists one of the last-ditch antibiotics has turned up in the UK, the BBC reports.
The announcement brings the world one step closer to the Antibiotic Apocalypse, the day when all bacteria completely resist all available treatment.
That may sound hyperbolic, and, indeed, experts think the threat to public health at this time is low.
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But the bacteria that resists colistin - a last-resort antibiotic that is used only when all other antibiotics have failed - turned up in China earlier this year and wasn't expected in the UK for three years. It's spreading faster than expected.
And while resistance to colistin has turned up before, the strain that emerged in China last month has the unique ability to easily spread to other bacteria.
"The transfer rate of this resistance gene is ridiculously high, that doesn't look good," medical microbiologist, Mark Wilcox, told the BBC in November.
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The biggest fear? That the gene will attach itself to the strains that cause problems in hospitals. That would be a major medical setback.
"Do I fear we'll get to an untreatable organism situation? Ultimately yes," Wilcox added.
Other scientists are less concerned, pointing out that there are other last-resort antibiotics and that combinations of antibiotics may be effective when one single antibiotic is not.
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Also, dose matters. A large enough infusion of colistin may kill the wiley mutation.
Meanwhile, the UK will be watching the gene closely.
"We are enhancing our surveillance for colistin resistance," a spokesperson told BBC.