Researchers in China recently found E.coli bacteria that are resistant to the antibiotic colistin, often called the antibiotic of last resort. While experts have been warning that the finding heralds a post-antibiotic era what is concerning health care professionals is that the circle of DNA that makes the bacteria resistant to colistin can be passed on to other strains of harmful bacteria.
This circle of DNA, known as MCR-1, was found on a circular structure of DNA known as a plasmid. Plasmids carry “optional extras” for bacteria: genes that are not essential for survival but can provide a benefit. In this case, surviving in the presence of colistin. Some plasmids can be copied and passed on to other bacteria, giving them the optional extras.
