Drug-resistant gene goes from pig farms to patients worldwide

A troublesome gene that is resistant to an antibiotic often used as a last resort has been tracked from its origins on Chinese pig farms to hospital patients worldwide in a new study led by UCL and Peking University People's Hospital. The study, published , found that the mcr-1 gene, now present across the globe, can be tracked to a single event around 2005 when it moved from pigs into pathogens that affect humans. "The speed at which mcr-1 spread globally is indeed shocking," said the study's lead author, Professor Francois Balloux (UCL Genetics, Evolution & Environment). The mcr-1 gene makes bacteria resistant to colistin, which is one of the very few drugs effective against multi-drug resistant infections. Colistin was discovered in the 1950s but has until recently been mostly used in pig farming due to its severe side-effects. With the recent increase in antibiotic resistance, it has now become widely prescribed in the clinic as a last-line drug for infections such as E. coli and Klebsiella pneumoniae . " Mcr-1 provides relatively low resistance, and mcr-1 strains can still be treated with colistin, but at far higher doses, which is obviously detrimental to the patients as colistin is fairly toxic.