New Antibiotic Resistant Superbug Found in the US

Recently, a new superbug was found in the US that contained resistance to a last resort antibiotic. Public health officials are concerned that we may be at the end of the line with the current arsenal of antibiotics. 

Back in April, a woman being treated at an outpatient military facility in Pennsylvania had an infection with a strain of E. coli bacteria that is resistant to an antibiotic known as colistin. Colistin is generally a last resort antibiotic since it can cause kidney problems. Fortunately for the woman (and the rest of us), the bacteria were successfully treated with other antibiotics.

Creating Superbugs

Unfortunately, the gene that makes the bacteria resistant to colistin, mcr-1, can be easily transferred to other bacteria. If the gene ends up in bacteria that are resistant to other antibiotics, it could potentially create more dangerous types of superbugs.

Are Farm Animals the Source?

In the US, 70 percent of antibiotics sold go to farm animals. Some of the antibiotics are used to treat diseased animals, but most are used to help animals put on weight faster and more efficiently. This "non-therapeutic" use of antibiotics can encourage resistance on the farm and into the environment through the animals' waste.

The colistin-resistant gene was first detected last year in pigs and people in China and has since turned up in a dozen cases on three continents. Colistin use in agriculture is thought to be where the mcr-1 gene emerged. US officials have also found two other strains of E. coli bacteria with the same colistin-resistant gene in samples taken from pigs. Because the gene was found in three different strains of bacteria, it has been suggested that mcr-1 is being transferred through multiple routes, which then enter the US.

Protecting Public Health

Public officials' main concern is that this gene will end up in bacteria that are currently only treatable with colistin. To prevent this, researchers are continuing surveillance to identify the emergence of the gene. Officials are also calling for better stewardship of the antibiotics currently available. The European Union has banned the use of antibiotics to accelerate growth in animals. In order to protect public health, it may be appropriate for the US and China to do the same.


Image "E. coli Bacteria" by NIAID on Flickr used under a Attribution-ShareAlike 2.0 Generic license.