Mysterious gene found in Georgia sewer water resists the most powerful antibiotics

January 14, 2022, 6:36 PM UTC

A recently discovered gene has been detected in sewer water in Georgia that causes bacteria to be resistant to one of the world’s most powerful antibiotics.

The MCR-9 gene found in Georgia creates antimicrobial resistance against colistin, the “last resort” antibiotic named so because it can kill infections that other antibiotics cannot. MCR was first discovered in 2016 and has since spread, threatening antibiotic resistance to the point that it is “one of the top 10 global public health threats facing humanity,” according to the World Health Organization.

The study, conducted by the University of Georgia’s Center for Food Safety and published in the Journal of Global Antimicrobial Resistance, notes that the prevalence of the bacteria in Georgia appears to be widespread. Not only did the researchers find the gene in the first sample they took, but they also found it in the bacteria Morganella morganii, which they don’t commonly test.

Also worrying, the MCR gene was found in plasmids, a DNA molecule found in a cell that has the ability to jump from one type of bacteria to another. This means bacteria like E. coli or salmonella that commonly cause outbreaks in humans could carry MCR, turning them from treatable illnesses to potentially deadly infections.

How did it end up in Georgia? 

MCR is understood to have spread from the agriculture industry in China and India, where the colistin antibiotic was used to treat livestock. The practice was banned in the U.S., and China and India have both since ended the practice in order to slow the spread of antimicrobial resistance. 

But despite best efforts, MCR was still found in sewage water in urban Georgia, indicating that it may have a foothold in the U.S. 

According to Issmat Kassem, an assistant professor at University of Georgia’s College of Agricultural and Environmental Sciences, who led the study, “The findings were kind of expected,” he tells Fortune.  

“We live in a connected world, so if there is a problem elsewhere, it usually finds its way to other parts of the world,” he says.

Through global travel and the import of foods from other countries, resistance against antibiotics has gotten a lot worse. “If we don’t tackle it right now, we are jeopardizing human and animal medicine as we know it, and that can have huge repercussions on health and the economy,” Kassem says.

The UN Ad hoc Interagency Coordinating Group on Antimicrobial Resistance warned in 2019 that drug-resistant diseases could cause 10 million deaths each year by 2050, and could force up to 24 million people into extreme poverty by 2030.

“We’re not talking about something that is distant future. We’re living the antimicrobial resistance crisis,” Kassem says. 

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