Gene chips used to distinguish ventilator-associated pneumonia from underlying critic...( St. Louis Feb. 13 2008 Critically ...)

St. Louis, Feb. 13, 2008 Critically ill patients who need a ventilator to breathe face a high risk of pneumonia. The lung infection, however, is exceedingly difficult to diagnose because a patient's underlying condition often skews laboratory test results and masks pneumonia's symptoms a reality that can delay appropriate antibiotic treatment.

Using gene chip technology, scientists at Washington University School of Medicine in St. Louis demonstrate for the first time they can distinguish pneumonia associated with ventilator use from other serious illnesses. The research, published Feb. 13 in the journal Public Library of Science One, suggests that the method may lead to early, more accurate detection and treatment of ventilator-associated pneumonia.

The team analyzed patterns of expression in more than 8,000 genes as patients on mechanical ventilators developed and recovered from pneumonia. They found changes in the activity of 85 genes could pinpoint early activation of the immune system in response to pneumonia, typically several days before clinical signs of the infection developed. By adding computational tools to their genomic analysis, the researchers also showed they could objectively monitor patients' recovery by graphing changes over time, creating a tool they called the "riboleukogram."

"This is an important step toward the development of a specific molecular test for diagnosing infection in particular pneumonia and predicting patients' recovery," says J. Perren Cobb, M.D., director of Washington University's Center for Critical Illness and Health Engineering and an intensivist at Barnes-Jewish Hospital. "If we could determine which patients are destined to develop pneumonia based on early changes in the activity of genes that regulate immune response, we could give them antibiotics sooner, with the hope that we might be able to prevent or curtail the infection."

As one of the more common and deadly hospital-a
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