The day that doctors, scientists and health experts have long feared and continually warned about may have arrived, as a mutation discovered in people and livestock in China has been found to make bacteria resistant to all antibiotics – including “last resort” drugs.
A gene known as MCR-1 is becoming more common in bacteria found in China. The mutation allows bacteria to resist a group of harsh antibiotics known as polymyxins, specifically a drug called colistin. Colistin is considered the absolute last line of defense against bacteria when all other antibiotics have failed, but not even it can knock out the newly discovered pathogen. These MCR-1 genes are basically invincible and they could theoretically end up affecting all infectious pathogens. Time reports:
“A new report found bacteria resistant to colistin, a drug used when all other treatments have failed, in 16 patients, 15% of raw meat samples and a fifth of the animals tested. The mutation that made the bacteria resistant to the drug is called the MCR-1 gene, and spread resistance between various bacteria including E. coli.” 
The World Health Organization (WHO) warned in 2012 said that colistin was vital to human health. Despite the WHO’s classification, farmers around the globe continued feeding the antibiotic to their animals in large quantities to fatten them up. Use of colistin, the most widely used polymyxin, is especially widespread in China, where farmers give it to pigs and chickens. 
Experts say it might not be long before the world is struggling to cope with the spread of uncontrollable superbugs. MCR-1 seems to move easily between the strains of E. coli and other common bacteria, including Klebsiella and Pseudomonas, which cause many blood, urinary and gut infections. Chinese researchers wrote in the journal Lancet Infectious Diseases that these germs will likely put people in mortal danger. Based on their horrific findings, the team predicts a return to the Dark Ages. 
“These are extremely worryingly results,” professor and co-author on the study Liu Jian-Hua, from China’s Southern Agricultural University, said in a press release.
Liu and his colleagues warn that while it might seem smart to limit the use of colistin, at this point it’s just too late. The bacteria seem to hang on to the plasmid even when the antibiotic isn’t being used, suggesting that the problem is here to stay.
In the U.S., we haven’t fed colistin to livestock en masse, but an estimated 70% of antibiotics considered vitally important to human health are used in farm animals and one day we’ll likely need drugs like colistin to fight previously easy-to-treat bugs. 
Antibiotic resistance kills some 700,000 people worldwide each year. That number is expected to climb to 10 million by 2050.
 New Scientist