A gene that lets bacteria resist polymyxins—the last line of antibiotic defense we have left—has shown up in widespread bacteria samples from pigs and patients in south China, including strains with epidemic potential.
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 among different bacterial populations.
“The emergence of the MCR-1 gene in China heralds a disturbing breach of the last group of antibiotics—polymixins—and an end to our last line of defense against infection,” says study author Timothy Walsh, professor at the Cardiff University School of Medicine. The research appears in The Lancet Infectious Diseases.
“The rapid spread of similar antibiotic-resistant genes such as NDM-1 suggests that all antibiotics will soon be futile in the face of previously treatable gram-negative bacterial infections such as E. coli and salmonella.
“Our investigations in China found that MCR-1 is already prevalent in E. coli samples found in live animals and meat products, and in a small number of human cases,” says Walsh, who worked with colleagues at South China Agricultural University.
“We now have evidence to suggest that MCR-1-positive E. coli has spread beyond China, to Laos and Malaysia, which is deeply concerning.
“The potential for MCR-1 to become a global issue will depend on the continued use of polymixin antibiotics, such as colistin, on animals, both in and outside China; the ability of MCR-1 to spread through human strains of E. coli; and the movement of people across China’s borders.
“MCR-1 is likely to spread to the rest of the world at an alarming rate unless we take a globally coordinated approach to combat it.”
Source: Cardiff University