New blood test may prevent antibiotics misuse

Scientists are developing a rapid blood test that can determine whether a respiratory illness is caused by infection from a virus or bacteria so that antibiotics can be more precisely prescribed.
Researchers at Duke University in US have developed 'gene signatures,' patterns that reflect which of a patient's genes are turned on or off, to indicate whether someone is fighting infection from a virus or bacteria. Results can be derived from a small sample of the patient's blood.
The signatures were found to be 87 per cent accurate in classifying more than 300 patients with flu viruses, rhinovirus, several strep bacteria and other common infections, as well as showing when no infection was present.

Researchers are a significant step closer to developing a rapid blood test that could be used in clinics to distinguish bacterial and viral infections and to guide appropriate treatment.
"A respiratory infection is one of the most common reasons people come to the doctor. We use a lot of information to make a diagnosis, but there's not an efficient or highly accurate way to determine whether the infection is bacterial or viral," said Ephraim L Tsalik from Duke University.
"About three-fourths of patients end up on antibiotics to treat a bacterial infection despite the fact that the majority have viral infections. There are risks to excess antibiotic use, both to the patient and to public health," Tsalik added.

Participants with respiratory problems were enrolled during visits to emergency departments at five hospitals. The technique is more accurate than other tests that look for the presence of specific microbes, researchers said.

More precise ways of distinguishing infections could not only reduce unnecessary use of antibiotics, but also lead to more precise treatments of viruses, researchers said.
"Right now, we can give patients Tamiflu to help them recover from an influenza infection, but for most viral infections, the treatment is fluids and rest until it resolves," said Geoffrey S Ginsburg from Duke University.
"In the next five to 10 years, we will likely see new antiviral medications for common bugs like respiratory syncytial virus (RSV) and even rhinovirus, (the predominant cause of the common cold), and guiding treatment choices will be even more important," he added.

The findings were published in the journal Science Translational Medicine.