New gene that makes common bacteria resistant to last-line antibiotic found in animals and patients in China

A new gene (mcr-1) that enables bacteria to be highly resistant to polymyxins, the last line of antibiotic defence we have left, is widespread in Enterobacteriaceae taken from pigs and patients in south China, including strains with epidemic potential, according to new research published in The Lancet Infectious Diseases. The mcr-1 gene was found on plasmids, mobile DNA that can be easily copied and transferred between different bacteria, suggesting an alarming potential to spread and diversify between different bacterial populations. “These are extremely worrying results. The polymyxins (colistin and polymyxin B) were the last class of antibiotics in which resistance was incapable of spreading from cell to cell. Until now, colistin resistance resulted from chromosomal mutations, making the resistance mechanism unstable and incapable of spreading to other bacteria,”explains author Professor Jian-Hua Liu from South China Agricultural University in Guangzhou, China. “Our results reveal the emergence of the first polymyxin resistance gene that is...