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Surviving Sepsis: New Device Speeds ID of Dangerous Bacteria

Nearly two years after her teenage daughter lost all four limbs to a dangerous bloodstream infection, Patricia Kirven is stunned at how little most people know about sepsis.

“You can ask the average person on the street and they don’t know what it is,” said Kirven, mother of Whitney Mitchell, now 20. “I have a friend who says that sepsis is the killer you’ve never heard of.”

Only high-profile cases seem to attract attention, like Whitney Mitchell's disfiguring infection, or the recent death of a 12-year-old New York boy, Rory Staunton, who developed severe septic shock two days after a minor gym class cut.

That’s despite the fact that hospital stays for sepsis in the U.S. have more than doubled in recent years, accounting for about 1.6 million hospitalizations a year and requiring treatment for some 4,600 new patients every day, according to a 2011 report from the Agency for Healthcare Research and Quality. 

The infection -- also known as septicemia or bacteremia -- can be sudden, capricious and difficult to identify, masquerading as a minor injury or illness that erupts into full-blown, whole-body organ failure within hours or days.

The mortality rate is alarming -- between 20 percent and 50 percent -- and largely depends on how quickly victims are diagnosed and treated with powerful antibiotics to battle the bacteria racing through their systems. Among those who live, amputations are common after the infection leads to tissue death in the limbs. 

In Whitney Mitchell’s case, a lawsuit accuses doctors at the Medical City Dallas Hospital of not giving her appropriate antibiotics for 38 hours after she showed up in the emergency room. In Rory Staunton’s case, his parents told the New York Times that critical medical information was ignored at NYU Langone Medical Center and that the signs of sepsis were disregarded. In both cases, critics said the victims were sent home from the emergency room before returning a day or so later in life-threatening condition.

“Getting a quick answer is a matter of life and death,” said Preeti Pancholi, an assistant professor of pathology and director of clinical microbiology at The Ohio State University Medical Center.

That’s why her hospital recently joined with five others across the country to test a device approved in June by the federal Food and Drug Administration that experts believe could drastically change the way sepsis infections are detected and managed.

About the size of a small microwave oven, the Verigene Gram-positive Blood Culture Nucleic Acid Test is the first system approved by the FDA to identify quickly certain bacteria responsible for bloodstream infections -- and whether some are resistant to the top drugs used against them.

Instead of the three days required for a traditional blood culture panel, results from the Verigene test come back within three hours, identifying up to a dozen specific bacteria known to cause sepsis, including strains of Staphylococcus, Streptococcus, Enterococcus and Listeria.

Plus, the test can tell whether the germs are Methicillin-resistant Staph aureus, or MRSA, or vancomycin-resistant Enterococci, or VRE, two of the toughest pathogens around.

Ledeboer, like Pancholi, agreed to participate in a seven-month clinical trial of the device produced and manufactured by Nanosphere Inc., of Northbrook, Ill.

Two weeks ago, Ledeboer, who said he has no financial ties to the product, went live with the Verigene test.

“In those two weeks, we’re seeing that patients are in fact being treated more appropriately sooner,” he said.

The reason is this: When patients come in with signs of suspected sepsis, including fever, low blood pressure and a racing heartbeat, it can be difficult for doctors to be certain it's a bloodstream infection and not another problem. Once they do confirm sepsis, doctors need to treat the patients fast. A 2010 study in the journal Critical Care Medicine found that for every hour of delay in administering antibiotics, mortality rose by 7.6 percent.

To that end, they break out what Ledeboer calls the “big guns” of antibiotics, the broad-spectrum drugs that can treat many pathogens at once. The trouble is, many bacteria are becoming resistant to antibiotics, meaning the treatments would be either be useless against the infections -- or they’ll help create the next generation of even tougher bugs.

“What we’re seeing now is that if you present with sepsis or any Gram-negative infection in New York City, you run a 30 percent risk of a pan-resistant organism,” Ledeboer said.

That is, an infection that virtually can’t be cured.

With the Verigene test, quick results mean doctors know faster exactly which bacteria they’re up against -- and whether the bugs are already resistant to top drugs.

“That’s a big change,” said Nathan Ledeboer, medical director of the clinical microbiology and molecular diagnostics laboratories at the Medical College of Wisconsin. “We don’t have to wait three days any more to get appropriate antibiotics on board.”

“It means patients are going to get out of the hospital faster, out of the ICU faster and it increases their chances of surviving sepsis,” Ledeboer said.

The test works by mapping the genome of a particular bacterium and capturing it on a glass slide, said Bill Moffitt, president and chief executive of Nanosphere. If that bacterium is present in the blood sample, it will bind to the material on the slide. Then the test uses silver-coated gold nanoparticles to bind to the captured genetic sequence. When light is shined on the slide, if the spots light up, it means the bug is present in the sample.

In trials that compared the Verigene test to traditional cultures and then verified them at an independent laboratory, the new device had a very high rate of accuracy, at least above 95 percent said Pancholi.

FDA officials based their approval decision on a study of 1,642 patient blood samples that compared traditional methods with the Vergiene test, with accuracy ranging from 93 percent to 100 percent.

Since the FDA approval, more than 200 hospitals have expressed interest, Moffitt said. The Verigene units cost between $50,000 and $100,000 apiece. The test panels cost about $75 each.

But Moffitt and Ledeboer estimate that the tests could significantly reduce the current $20,000 cost of a single sepsis workup.

Independent infectious disease experts were quick to praise the new technology.

“This seems to be the first product from our molecular revolution,” said Dr. William Schaffner, chair of the department of preventive medicine at Vanderbilt University. Quicker detection and treatment of sepsis may be the only way to start to cut the rising mortality caused by the insidious bacteria, he added.

“It’s a very exciting development," he said.

For victims already ravaged by sepsis, such progress is bittersweet. If there had been a quicker test to identify specific bacteria, perhaps doctors would have identified the source of Whitney Mitchell's infection, said Kervin, her mother. 

"They never could tell us exactly what it was," she said. 

Reached by phone at the Dallas home she shares with her mom, Whitney Mitchell said she was hospitalized for months after her amputations in 2010. She now spends her days going to physical therapy sessions, doing exercises at home to strengthen her shortened limbs and trying as best she can to resume her life. She's got a lively online presence and a supportive community. Although she has prostheses for her arms, including one set she calls her "pretty hands," she said she's gotten good at typing using a tough nub on her residual arm. 

"I'm always on the computer," said Mitchell. "I have a callus on the tip of it because I type so much."

Bob Bergert, the lawyer representing Medical City Dallas Hospital and the medical team involved said that they have "great empathy" for Mitchell and her family, but added that she received "appropriate care based on the facts and resources available to the healthcare providers."

Still, at age 20, Whitney Mitchell faces a lifetime of prosthetics and several additional surgeries. Kervin said she wishes there had been a test, a tool, anything that would have stopped the infection that raced through her daughter's body.

“It makes me happy and sad,” Kervin said. “Sad that it wasn’t there for my daughter, but glad that it will help other families from going through the pain we’re going through.”



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