Chinese scientists have reportedly identified a gene that makes Enterobacteriaceae, a family of gram-negative bacteria, resistant to “last-resort” drugs known as polymyxins.


“The polymyxins (colistin and polymyxin B) were the last class of antibiotics in which resistance was incapable of spreading from cell to cell”, he explained. These have become known as “last resort” antibiotics, increasingly used to treat infections that resist every other kind. “Although now confined to China, mcr-1 is likely to emulate other resistance genes… and spread worldwide”. This gene was found on a piece of bacterial DNA that can be transferred between bacteria.

Should bacteria become completely resistant to treatment, it could plunge the world into what the BBC refers to as “the antibiotic apocalypse“, a period in which common infections could be fatal because medicine proves ineffective, and surgeries and cancer treatments requiring antibiotic use would be placed in jeopardy.

“These are extremely worryingly results”, said Liu Jian-Hua, a professor at China’s Southern Agricultural University and co-author of the study. (It’s encouraging that such a project exists.) They say they first perceived a colistin-resistant E. coli in 2013, in a pig from an intensive farm near Shanghai, and then noted increasing colistin resistance over several years.

This prompted the researchers to collect bacteria samples from pigs at slaughterhouses across four provinces and from pork and chicken sold in 30 open markets and 27 supermarkets across Guangzhou between 2011 and 2014. On further examination, the researchers also found mcr-1-containing plasmids in E. coli and Klebsiella pneumoniae isolated from a small number of patients in hospitals in Guangdong and Zhejiang provinces. The MCR-1 gene was also found in E coli collected from 78, or 15 percent of 523 samples of raw meat and 166 or 21 percent of 804 live animals.

Professor Laura Piddock, from the campaign group Antibiotic Action, said the same antibiotics “should not be used in veterinary and human medicine“. So, the development of resistance to colistin may have affected the bacteria discovered by the team in China in other ways – ways that are more harmful to the bacteria than beneficial.

The World Health Organization (WHO) classified Colistin in 2012, as the most broadly used polymyxin and the most important for human health.

The lower infection rate among humans suggests the resistant bacteria passed from animals to people, the study found.

Worse still, MCR-1 enables the bacteria to spread easily from one strain or species to another, according to the study by the researchers which was published in the respected medical journal ‘Lancet Infectious Diseases‘.

Chinese scientists identified bacteria in a position to shrug off the drug – colistin – and livestock.

Scientists have found strains of E.coli and other diseases, which can together cause serious infections and even death.

Experts have described the discovery as “worrying”, particularly as the resistance is found to have spread between a range of bacteria.

China is one of the world’s biggest users of colistin for both livestock and aquaculture, the authors wrote.

Bacteria resistant to colistin discovered