New tool to distinguish between viral, bacterial infections

Scientists from the University’s National Institutes of Health-funded Respiratory Pathogens Research Center identified 11 genetic markers in blood that accurately distinguished between viral and bacterial infections (antibiotics help us fight bacterial infections, but aren’t effective and shouldn’t be used to treat viruses). The finding, published in the journal Scientific Reports, is important because physicians don’t have a good way to confirm bacterial infections like pneumonia and more-often-than-not default to an antibiotic.

“It’s extremely difficult to interpret what’s causing a respiratory tract infection, especially in very ill patients who come to the hospital with a high fever, cough, shortness of breath and other concerning symptoms,” said Ann R. Falsey, M.D., lead study author, professor and interim chief of the Infectious Diseases Division at UR Medicine’s Strong Memorial Hospital. “My goal is to develop a tool that physicians can use to rule out a bacterial infection with enough certainty that they are comfortable, and their patients are comfortable, foregoing an antibiotic.”

A group of 94 adults hospitalized with lower respiratory tract infections were recruited to participate in Falsey’s study. The team gathered clinical data, took blood from each patient, and conducted a battery of microbiologic tests to determine which individuals had a bacterial infection (41 patients) and which had a non-bacterial or viral infection (53 patients). Thomas J. Mariani, Ph.D., professor of Pediatrics and Biomedical Genetics at URMC, used complex genetic and statistical analysis to pinpoint markers in the blood that correctly classified the patients with bacterial infections 80 to 90 percent of the time.

“Our genes react differently to a virus than they do to bacteria,” said Mariani, a member of the Respiratory Pathogens Research Center (RPRC). “Rather than trying to detect the specific organism that’s making an individual sick, we’re using genetic data to help us determine what’s affecting the patient and when an antibiotic is appropriate or not.”

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