Virus or bacteria? New test should enable fast detection

Researchers are developing methods for rapid detection of the pathogen type
Antibiotics only work for a bacterial infection, they are absolutely powerless against viruses. Nevertheless, many patients still receive the special drugs for a viral infection. Now, however, a newly developed rapid test could remedy the situation. Because this should bring in the future within an hour clarity about the cause of an infection.
Antibiotics are ineffective against virus infections
The discovery of antibiotics is one of the most important developments in the history of medicine, because they can be used to treat life-threatening infections, such as a bacterial pneumonia can be cured. But the funds only help against bacteria. In common infectious diseases such. On the other hand, bronchitis or influenza are ineffective because they are usually caused by viruses. Nevertheless, many patients are also prescribed an antibiotic in this case, which can have nasty consequences. Because the excessive, improper use of the drugs leads to unwanted side effects and in the longer term may cause a decreasing effectiveness of the funds. In the US, President Barack Obama therefore set up a working group in September 2014 to develop a national action plan.

New test prevents unnecessary administration of antibiotics. Image: Gina Sanders - fotolia

Now the situation could be defused with the help of a new test. This is reported by a research team from Duke University in Durham (USA) in the journal "Science Translational Medicine". Accordingly, the method could analyze the activation patterns of certain genes ("gene signatures") and thus could achieve better results in a study in comparison to the common procalcitonin test (PCT test for short). It is planned that the new test could in the future clarify within one hour whether a bacterial or viral infection of the respiratory tract is present, the researchers said.

Doctors secure themselves with a prescription
"Respiratory infections are among the most common reasons people go to the doctor," said Ephraim Tsalik of Duke University in Durham (US), according to a statement from the university. About three-quarters of patients are prescribed antibiotics for treatment of a bacterial infection - although most are viral infections, Tsalik goes on to explain. Responsible for this is usually the unclear diagnosis, as physicians often can hardly distinguish a bronchitis from an incipient pneumonia. While the former is usually caused by viruses, pneumonia is mainly caused by an infection with bacteria - and therefore normally requires no antibiotic for treatment. Nevertheless, many doctors would as a precaution issue a prescription so as not to take any risks.

Nausea and fungal infections by antibiotics
But the excessive and improper use of antibiotics is not without consequences, because it threatens unpleasant side effects such. allergic reactions, gastrointestinal complaints or fungal infections. Public health is also seriously endangered, as many too frequent and incorrect uses mean that many bacterial pathogens are now insensitive to the drugs. "The increasing resistance of bacteria to antibiotics is a big problem," confirms Mathias Pletz, director of the Center for Infection Medicine and Hospital Hygiene at the University Hospital Jena, to the news agency "dpa". Therefore, it could not be postponed to reduce the use of antibiotics, Pletz continued.

As the University reports, Tsalik and his team first identified typical gene signatures in the blood that indicate whether the infection was caused by viruses or bacteria. Subsequently, they tested their newly developed procedure on five databases and just under 320 patients in outpatient clinics. Accordingly, in the majority of the patients (115 persons), the respiratory tract infection was caused by viruses (e.g., influenza or rhinoviruses), in 70 cases it was a bacterial infection. Another 88 people were affected by a non-infectious disease and the remaining 44 were healthy.

Test determines more cases than current PCT procedure
The test yielded an astounding result, as he found the cause of the discomfort more reliable than the current blood test for procalcitonin (PCT). According to the announcement, the new process provided clarity in 87 percent of the cases, while the widespread PCT test achieved a hit rate of 78 percent. The test will now be further developed so that he delivers a secure result within 60 minutes in the future. This could be a tremendous relief in everyday clinical practice, as the current technology takes up to ten hours to determine.

Test should be feasible with existing equipment
"We are working to develop a test that can be performed on existing facilities in most clinical laboratories. We believe this could have a real impact on the appropriate use of antibiotics and guide the use of antiviral treatments in the future, "said senior author Christopher W. Woods of Duke University. Mathias Pletz also sees potential in the current study: Accordingly, it is a "very thoughtful study", for which the scientists would have included next to people with different genetic background and sick people without infection. "The procedure offers a view into the future", the expert told the "dpa".

Alternatively, however, there is already another way to reduce antibiotic use. According to Pletz, a study from Hanover has shown that it is often enough if the doctor does issue a prescription for antibiotics, but please do not redeem it immediately. Instead, patients were asked to call the practice the next day to check the outcome of the PCT test. Since the antibiotics are to be used only for a bacterial cause, the use has fallen by about 40 percent, so Pletz. (No)