One thing that makes it hard for doctors to treat respiratory infections is the lack of diagnostic exams possible to determine if the pathogen involved is a bacteria or virus. Researchers from Duke Health developed a test that can determine the exact cause of infection so appropriate antibiotics can be prescribed.

A team of infectious disease and genomics experts developed a test called gene signatures which are patterns that show which genes of the patient are turned on or off. Results are derived from just a small sample of blood and it can already determine which type of infection the body's immune system is fighting.

"Antibiotics treat bacteria, but they do not treat viruses. That's why distinguishing between these various causes of illness is very important to get the right treatment to the right patient, and to offer a prognosis for how the patient is likely to do," explained Dr. Ephraim Tsalik, author of the study.

Doctors use a lot of information to land to a diagnosis but with diagnostic procedures present today, there is no efficient or accurate way to distinguish between the two pathogens. According to the authors, about three quarters of patients end up on antibiotics even if majority have viral infections.

The excess use of antibiotics entail health risks to both the patient and to the public. It may lead to antibiotic resistance that can pose serious health effects in the future. Viral infections usually go without needed medications but with just fluids and rest.

The new test looks for genetic signature in samples of blood from patients to determine if the pathogen causing the disease is a bacterium or virus. The researchers found that the test was 87 percent accurate in classifying more than 300 patients with flu, common colds or strep infections.

With the new discovery, it will be easier for physicians to properly prescribe antibiotics to prevent its over usage and the emergence of superbugs that are very hard to treat.

Respiratory infections are one of the most common reasons for doctor visits. Acute respiratory infections (ARI's) cause around 4.25 million deaths each year. A report by the World Lung Foundation says that ARIs are the third largest cause of mortality worldwide and the top killer in low and middle income countries. 

Photo: William Brawley | Flickr