Doctors find alarming superbug in Pennsylvania woman |
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Ben Schmitt
This 2006 colorized scanning electron micrograph image made available by the Centers for Disease Control and Prevention shows the O157:H7 strain of the E. coli bacteria. On Wednesday, May 26, 2016, U.S. military officials reported the first U.S. human case of bacteria resistant to an antibiotic used as a last resort drug. The 49-year-old woman has recovered from an infection of E. coli resistant to colistin.

Worrisome bacteria resistant to the most powerful antibiotics have been discovered in a Pennsylvania woman, marking the first time doctors found this type of superbug in the United States, health authorities said Thursday.

“This is highly significant,” said Dr. Yohei Doi, a University of Pittsburgh infectious disease professor who specializes in antimicrobial resistance research. “We knew this was coming. It was only a matter of time.”

The new strain was highlighted by Department of Defense researchers in a study published Thursday in Antimicrobial Agents and Chemotherapy, a publication of the American Society for Microbiology.

Researchers wrote that the Pennsylvania finding “heralds the emergence of a truly pan-drug resistant bacteria.”

“We know now that the more we look, the more we are going to find,” Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, said during a speech at the National Press Club in Washington. “The more we look at drug resistance, the more concerned we become. The medicine cabinet is empty for some patients. It is the end of the road for antibiotics if we don’t do something.”

The E. coli bug, called plasmid-mediated colistin resistance mechanism or MCR-1, was discovered in the 49-year-old woman’s urine. The study’s authors wrote the woman had a urinary tract infection, but CDC spokesman Tom Skinner said that was an error because the woman carried the bacteria but did not develop an infection.

Skinner said experts are working with state health officials to interview the woman and her family and figure out how she might have been exposed to the bacteria, including whether she might have picked it up during a hospital stay.

No other details about the woman were immediately available.

She has not traveled outside the United States within the past five months, according to the study.

The Pennsylvania Department of Health is working with the CDC and Defense department to further investigate the matter, said spokesman Wes Culp.

“We are taking the emergence of this resistance gene very seriously, and we will take necessary actions to prevent MCR-1 from becoming a widespread problem with potentially serious consequences,” Gov. Tom Wolf said in a statement.

The bacteria has a genetic composition that makes it resistant to a so-called antibiotic of last resort, colistin.

“Antibiotics of last resort are generally reserved for very ill patients with infections difficult to treat because of their resistance to other antibiotics,” Doi said. “Some, like colistin, can be quite toxic and cause renal failure.”

Doi said colistin resistance has been seen in China and Europe but not in the United States. The CDC has identified superbugs as a public health concern that continues to worsen. Experts attribute much of the superbug escalation to society’s overuse of antibiotics. When doctors unnecessarily prescribe antibiotics for a viral infection that won’t respond, they’re essentially destroying beneficial bacteria needed to protect against other infections.

“This new case is really concerning because of the increase in antibiotic resistance,” said Allegheny Health Network’s Dr. Thomas Walsh, who works as Allegheny General Hospital’s medical director of the antimicrobial stewardship program. “We are going to see this more and more frequently if we continue to have rampant inappropriate use of antibiotics that promotes all this resistance.”

The CDC estimates that more than half of the antibiotics given for upper respiratory infections and nearly a third of antibiotics used in hospitals are prescribed inappropriately. During a visit to Pittsburgh in October, Dr. Sanjay Gupta, neurosurgeon and CNN chief medical correspondent, called antibiotic resistant bacteria the most important medical story in the news.

Walsh agrees.

“Antibiotic resistance in general is the largest threat that’s going to face us in medicine,” Walsh said. “We have out-of-control antibiotic resistance and fewer and fewer antibiotics coming down the pipeline to treat these superbugs.”

A sample of the bacteria was sent to Walter Reed National Military Medical Center, according to the study.

“To the best of our knowledge, this is the first report of MCR-1 in the United States,” its authors wrote.

Doi said it’s paramount that drugmakers develop new forms of antibiotics to counter the superbug scourge. The problem, he said, is that antibiotics aren’t profitable when compared to drugs for ailments such as diabetes and high blood pressure.

“In the private sector, for many companies it doesn’t make financial sense,” he said. “It’s getting in the way of the necessary innovation in the field.”

Ben Schmitt is a Tribune-Review staff writer. Reach him at 412-320-7991 or [email protected].

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