Looking through the patient’s chart, an infection-control consultant at the National Institutes of Health noticed something troubling.
The patient, a 43-year-old woman from New York, was scheduled to be admitted to NIH’s Clinical Center, a research hospital for people enrolled in clinical studies and drug trials, in June 2011.
The patient had a rare lung disease, but the consultant spotted another problem, one that was potentially even more serious: She had been colonized by a dangerous, drug-resistant bacterium the likes of which the Clinical Center had never seen before. It was called KPC klebsiella.
Klebsiella itself is an ordinary bug, one of many bacteria that reside in our intestines. But bacteria can exchange genetic code with each other, and this particular strain of klebsiella had acquired a molecule of DNA known as KPC.
The KPC molecule deactivates carbapenem, an antibiotic that’s the drug of last resort for bacterial infections. For severely ill patients, such as many of those at the Clinical Center, the most likely result of a KPC-klebsiella bloodstream infection is death.
The job of keeping the bug from spreading to other patients fell mainly to Tara Palmore, the Clinical Center’s deputy hospital epidemiologist. Although Palmore and other administrators were nervous about the patient’s arrival, they believed they could contain the bacterium and prevent an outbreak.
Palmore followed a strict protocol, outlined by the Centers for Disease Control and Prevention (CDC): Everyone entering the patient’s room was required to wear protective gloves and gowns. Caregivers were told to use disposable products whenever possible. These measures, known as “enhanced contact isolation” would be maintained both in the ICU and later in the patient’s room.
The patient arrived on June 13, 2011. She spent 24 hours in the ICU, then was transferred to a private room. Later that month, she returned briefly to the ICU, again under enhanced isolation. Afterward, groin and throat cultures were collected from other ICU patients; none tested positive. On July 15, five weeks after the patient checked into the Clinical Center, she was discharged. The testing continued for another week. All results were negative. It seemed the hospital was in the clear.
Then, on August 5, Palmore got a call from Adrian Zelazny, head of the microbiology lab. A 34-year-old male cancer patient in the ICU had developed an infection. It was KPC klebsiella.
Palmore was puzzled. The cancer patient had never overlapped in the ICU with the first colonized patient. Was this a new, independent infection, or had the bacterium found a way to hide, undetected, in the hospital for weeks before spreading to other patients? The microbiology lab could say only that the two strains were similar.
Ten days later, a third patient, a 27-year-old woman, tested positive. Within months, both the second and third patients would die from sepsis brought on by the infection. (NIH declined to provide patient names for this story, citing privacy concerns.)
And that was just the beginning. Before the outbreak was over—if it was over—seven other patients would die. “The system broke,” says Dr. John Gallin, director of the Clinical Center. “Something went wrong.”
But this isn’t a story about wrongdoing. It would be reassuring if it were.
For four months, the staff at NIH mounted an extraordinary effort to contain the outbreak, one that involved both old-fashioned, epidemiological detective work and cutting-edge genomic science. The story of that response—and how doctors and scientists at one of the world’s most advanced medical facilities were bested by a microscopic organism—illustrates the dangers we face as we edge closer to a future in which antibiotics no longer reliably work.
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At the Clinical Center’s groundbreaking in 1951, President Harry Truman declared victory over the terrible infectious diseases of his childhood—typhoid, diphtheria, tuberculosis, and pneumonia. “It is safe to say that we have successfully conquered the infectious diseases,” he said.
He was wrong. Infections in medical facilities now kill some 99,000 Americans a year—more than three times the number of lives lost every year to car accidents or gun violence. That’s roughly the equivalent of a fully loaded 737 jet crashing every day and killing every passenger. Check into a hospital and there’s a 5-percent chance you’ll acquire an infection. If you do, there’s a 6.5-percent chance you’ll die as a result.
By overprescribing antibiotics for ourselves and the animals we eat, we humans have done something foolish—we’ve waged a war on microbes that has only made them stronger. According to the CDC, more than 70 percent of the bacteria involved in hospital-acquired infections now have at least some resistance to antibiotics. And the problem is getting worse.
In March, Dr. Thomas Frieden, head of the CDC, warned of the dangers posed by KPC klebsiella and other drug-resistant bacteria. “It’s not often that our scientists come to me to say that we have a very serious problem and we need to sound an alarm,” Frieden said on a conference call, “but that’s exactly what we’re doing today.”
Frieden described “nightmare bacteria” that posed a triple threat: “First, they’re resistant to all or nearly all antibiotics, even some of our last-resort drugs. Second, they have high mortality rates. They kill up to half of people who get serious infections with them. And third, they can spread their resistance to other bacteria.”
That last point is perhaps the most alarming. Think of KPC as a code that gives bacteria resistance to the last class of antibiotics we have that can stop infections—a code that klebsiella can share with other, more common bacteria. That means, Frieden said, “that we have only a limited window of opportunity to stop this infection from spreading to the community and spreading to more organisms.”
Beyond that window, things start to look pretty scary. “We have eight years until 15 percent of the people who come to us have serious infections that we will not have treatments for,” says Dr. Allison McGeer, an infectious-disease epidemiologist at Mount Sinai Hospital in Toronto, which confronted the first SARS outbreak in North America ten years ago.
“Right now, if you get a urinary-tract infection, the doctor pats you on the head and gives you an antibiotic,” says Dr. Brad Spellberg, an infectious-disease expert at UCLA. “People don’t die of urinary-tract infections. They are going to start to.”