Researchers have isolated a new bacteria carrying the gene responsible for drug resistance. Shigella flexneri is a main cause of diarrhea across the world, especially in low and middle income countries.

Date: March 6, 2018


Author: Lou Del Bello


Scientists are warning that the antibiotic resistance army has been joined by a new powerful enemy. For the first time, a team of researchers discovered that the gene responsible for drug resistance has spread to the bacteria Shigella flexneri, a main cause of potentially fatal diarrhea around the world.

In 2015, researchers discovered that the mcr-1 gene, which confers resistance to a “last resort” antibiotic called colistin, was spreading among pigs in Chinese farms via the gut bacteria Escherichia coli. Similar signs of resistance also emerged in farms in Denmark, France, the Netherlands and Thailand. For decades, antibiotics have been widely used in farming because they lessen disease risk, boosting animal growth and maximizing profits. Yet this practice has also made an increasing number of bacterial strains resistant to the agents designed to kill them off.

The latest research, published in the journal Applied and Environmental Microbiology, screened a sample of more than 2000 bacteria taken from animal feces on a farm, from patients, and from the environment in China. The team identified the mcr-1 gene on a transferable plasmid, a genetic element that can jump between bacterial species, carrying drug resistance with them — in this case, from S. flexneri to E. coli and potentially other bacterial strains too.