Results could speed up diagnosis, improve treatment decisions, study authors say
By Robert Preidt
HealthDay Reporter
WEDNESDAY, Sept. 17 (HealthDay News) -- A new genetic test that distinguishes between viral and bacterial infections could help fight antibiotic resistance and quickly detect new diseases, according to a new study.
The immune system responds differently when battling a viral or bacterial infection, and these differences are evident at the genetic level.
This new blood test detects a specific genetic signature that a person's immune system expresses in response to viruses, the Duke University Medical Center researchers said.
They assessed the test in 102 people and found that it was more than 90 percent accurate in distinguishing between viral and bacterial infections in people with respiratory illnesses, according to the study, which was published in the Sept. 18 issue of the journal Science Translational Medicine.
The findings move the test closer to clinical use, where it could help patients get quicker diagnoses and treatments, while reducing the unnecessary use of antibiotics that don't work on viral infections, the researchers said.
"In instances such as pandemic flu or the corona virus that has erupted in the Middle East, it's extremely important to diagnose a viral illness far more accurately and speedier than can be done using traditional diagnostics," study co-senior author Dr. Geoffrey Ginsburg, director of genomic medicine and a professor of medicine, said in a Duke news release.
Current tests rely on evidence of the microbe in a patient's blood and require knowledge of that particular bug to detect it. The new test doesn't have those limitations and could be used to detect new diseases, including potential bioterrorism threats, according to the news release.
"This is important not only in viral pandemics where infection may be caused by unknown viruses but also in routine care where the decision to treat or not with antibiotics is paramount," study lead author Dr. Aimee Zaas, associate professor of infectious diseases and international health, said in the news release.
The researchers plan large studies and say they're trying to reduce the amount of time it takes to get test results. The test currently takes 12 hours.

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While overall rates still low for kids, study finds infants and black children face higher risk
By Serena Gordon
HealthDay Reporter
MONDAY, Sept. 23 (HealthDay News) -- Although rates of infection with methicillin-resistant staphylococcus aureus (MRSA) are declining among American adults, the rates among children remain largely unchanged, a new government study finds.
In addition, MRSA disproportionately affects infants less than 3 months old and black children, according to the report from the U.S. Centers for Disease Control and Prevention, published online Sept. 23 and in the October print issue of Pediatrics.
MRSA is considered a "superbug" because it's resistant to nearly all treatments, including the powerful antibiotic methicillin. The most recent figures from the CDC, reported in the Sept. 16 issue of JAMA Internal Medicine, found that 30,000 fewer MRSA infections occurred in 2011 compared to 2005.
Fortunately, rates in children are much lower than what has been reported in adults, according to the latest study's lead author, Dr. Martha Iwamoto, a medical epidemiologist with the CDC. However, the number of cases in children didn't decline significantly from 2005 to 2010.
The one bright spot in the latest findings was in infants under 90 days old. "We found that the numbers of invasive MRSA infections among young infants are going down," Iwamoto said.
However, the incidence of infections in babies younger than 3 months was still significantly higher than in other children.
Rates of infections in black children were more than four times higher than in children of other races.
"We are making some progress in reducing the number of invasive MRSA infections in young infants in hospitals. However, more needs to be done, especially for children developing invasive MRSA outside of hospitals," she said.
MRSA can cause a variety of illnesses from skin infections to a life-threatening blood infection. These types of infections were initially prominent in hospital settings, but even as prevention measures have reduced the number of infections within hospitals, community-based infections have increased.
To better identify how this super bug is affecting infants and children, Iwamoto and her colleagues reviewed reports of MRSA infections across the United States from 2005 to 2010.
They found a total of 876 pediatrics cases, 39 percent of them in infants, according to the study.
A little more than one-third of the cases were hospital-onset infections, while 42 percent were community-associated infections, which can occur through skin-to-skin contact in schools or daycare centers. The remaining 23 percent were health-care associated community-onset infections.
The incidence of community-acquired infections rose by 10 percent during the study time period.
Iwamoto said that if rates are to drop for older infants, "we need to focus on prevention of MRSA infections outside of hospitals."
She said that while this study confirmed a racial disparity in MRSA infections, it's not clear why that disparity exists. The presence of underlying disease might increase the susceptibility to infection, or socioeconomic factors, such as household crowding, might play a role too, she said. Additional studies need to be done to understand why this disparity exists so that something can be done to address it, she said.

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