'Invincible' bacteria threatens global epidemic

Medicine's final line of defence against deadly disease has been breached, raising the spectre of a global epidemic, scientists say, after finding bacteria resistant to last-resort antibiotics.

The discovery could herald a virtual return to the Dark Ages, with doctors unable to control common germs like E. Coli, rolling back centuries of medical progress.

"These are extremely worryingly results," said Liu Jian-Hua, a professor at China's Southern Agricultural University and co-author of a new study.

Liu and his colleagues found a gene, called MCR-1, that allows bacteria to become resistant to a class of antibiotics known as polymoxins, which are used to fight superbugs.

The gene, which was detected in common but deadly bacteria such as E. Coli and K. Pneumoniae -- the cause of pneumonia and blood diseases -- effectively makes bacteria invincible.

Most worryingly of all, the gene is easily spread from one strain to another, said the study, which was published in The Lancet Infectious Diseases journal, prompting warnings they could have "epidemic potential".

Until now, rare cases of resistance occurred only through mutation in individual organisms, severely limiting transmission.

The World Health Organization (WHO) has already warned antimicrobial resistance may result in "a return to the pre-antibiotic era," where even small infections -- or cuts -- could prove fatal.

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