A strain of the E. coli bacteria. Credit Janice Carr/Centers for Disease Control and Prevention, via Associated Press For more than a decade, doctors and scientists have warned that evolving bacteria could soon lead to “superbug” germs resistant to all current antibiotics, ushering in a new era of medicine in the United States – and beyond.

The first such superbug has now been documented in the U.S., in a patient last month in Pennsylvania, as documented by military doctors.

It could be a grim milestone for modern medicine, according to experts.

“It is the end of the road for antibiotics unless we act urgently,” said Tom Frieden, director of the Centers for Disease Control and Prevention.

The 49-year-old woman was admitted to a clinic on April 26 with what appeared to be a urinary tract infection.

But the germs actually were E. coli carrying a new gene known as mcr-1, a strain infamous for its resistance to the last-defense antibiotic colistin, reported the scientists at Walter Reed National Military Medical Center, in the latest issue of the journal Antimicrobial Agents and Chemotherapy.

“The recent discovery of a plasmid-borne colistin resistance gene, mcr-1, heralds the emergence of truly pan-drug resistant bacteria,” the doctors wrote.

The mcr-1 gene was first identified in humans in a urine sample from the United Kingdom in 2008, and was also documented in a bloodstream culture in Italy shortly thereafter. It has also been documented in Chinese pigs.

But never before has it appeared in the U.S., according to the researchers.

Colistin has been around for decades, though it was mostly phased out by the 1970s due to its harsh side effects. But it has reemerged in recent years, due to increasing toughness and resistance of bacteria.

READ MORE: WHO to Fight Resistance to Antibiotic Resistance

The Pennsylvania woman was successfully treated with another antibiotic, and she has recovered. But experts said the development of the mcr-1 gene could be just another step toward the rise of a palette of superbugs.

“This is another piece of a really nasty puzzle that we didn’t want to see here,” said Beth Bell, a doctor who oversees the CDC’s emerging infectious disease programs.

In the U.S. already, antibiotic resistance accounts for an estimated 2 million illnesses and 20,000 deaths annually. The World Health Organization announced an initiative of combating drug resistance last year, But estimates still contend that an additional 10 million deaths worldwide could come from superbugs in coming years.


The Associated Press contributed to this report.