Experts are sounding the alarm about a cluster of four New York City hospital patients carrying an antibiotic-resistant "superbug" form of E. coli.
The E. coli harbored by the patients has an antibiotic resistance gene called mcr-1, which gives the bacteria resistance to colistin, an antibiotic of last resort against some multidrug-resistant infections, according to a team led by Dr. Anne-Catrin Uhlemann.
What's more, three of the four patients had no symptoms of E. coli -- raising the risk that the antibiotic-resistant bacteria could be unknowingly spread among people, Uhlemannand colleagues reported April 8 in the journal Antimicrobial Agents and Chemotherapy.
"While mcr-1 has been described from other parts of the world, it has been very rare in the U.S.," Uhlemann said in a journal news release. But the new report highlights the potential for the undetected spread of drug-resistant E. coli in U.S. hospitals, she said. Uhlemann is an associate professor at Columbia University's Vagelos College of Physicians and Surgeons.
One emergency medicine physician not part of the study said the news is troubling.
"The mcr-1 gene confers resistance to colistin, one of the 'last resort' antibiotics for treating gram-negative bacterial infections," said Dr. Robert Glatter, who practices at Lenox Hill Hospital in New York City.
The gene "has now been found in not only E. coli but in Salmonella, Klebsiella and different subtypes of Enterobacter bacteria. In fact this gene has been detected in bacteria in more than 30 countries in five continents since 2017," he said.
Whole genome sequencing revealed that the E. coli bacteria in each patient was closely related, but not identical.
"We then reviewed the clinical course of each individual and noted that the first patient had presented with an infection, whereas the other three only carried the bacteria in their feces," Uhlemann said.
In those latter cases, "none of these three patients developed an infection with these bacteria," she said.
The study was prompted by concerns about increasing rates of antibiotic resistance, a growing menace. According to the researchers, scientists predict that by 2050, antibiotic-resistant infections might cause more deaths than cancer.
According to Glatter, the undetected spread of bacteria with mcr-1 "has the potential to become a major threat to human existence if we are unable to contain its spread." He believes the new report "is a wake-up call to the ongoing threat to human health posed by antibiotic resistance."
The new findings "represent the earliest known documented health care-associated cluster of mcr-1 in the United States, and predates a recent report that occurred in 2017," Uhlemann noted.
The overuse of antibiotics in health care and agriculture "contributes to the ongoing dilemma of antibiotic resistance," as germs learn to work around the lifesaving drugs, Glatter said.
Overuse can occur when patients demand, and physicians supply, antibiotics for viral infections such a flu, for example. The drugs are only effective against bacteria, not viruses.