Identifying A New Way to Cut Unnecessary Antibiotic Use for Viral Respiratory Infections

Although lower respiratory tract infections (LRTIs) are often caused by viruses, patients often receive unnecessary antibiotics for the treatment of these infections. In a new trial sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), researchers are looking at how levels of 1 protein in the blood may help doctors correctly diagnose the cause of LRTIs.

Infections of the lower respiratory tract affect parts of the airways, including the trachea and the alveolar sacs in the lungs, which can lead to acute bronchitis, bronchiolitis, and pneumonia. Mild LRTIs can result in symptoms such as congestion, sore throat, cough, wheezing, and low-grade fever. Individuals with more severe LRTIs may experience higher fever, severe cough, wheezing, difficulty breathing, and other symptoms. A 2016 study by researchers from the Centers for Disease Control and Prevention (CDC) and the American Academy of Physicians noted that respiratory tract infections are the most common cause of most acute outpatient physician office visits; furthermore, about 41% of antibiotics prescribed for adults in ambulatory care visits are for respiratory conditions.

The CDC has found that at least 30% of antibiotic prescriptions in the United States are unnecessarily prescribed for conditions caused by viruses such as common colds, viral sore throats, bronchitis, and sinus infections. This excess of 47 million prescriptions each year is fueling the growing problem of antibiotic resistance and undermining the ability to fight life-threatening infections. By 2020, the CDC aims to cut those unnecessary prescriptions by half; public health officials have said that better diagnostic tools in doctors’ offices can play a key role in reaching that goal. In a recent press release, the NIAID, part of the National Institutes of Health (NIH), announced that it is sponsoring a new study to be led by Duke University’s Ephraim Tsalik, MD, PhD, that will look at blood levels of the protein procalcitonin, which researchers say may help determine if an LRTI will respond to treatment with antibiotics.

Healthy individuals produce small amounts of procalcitonin, a precursor to a hormone which helps regulate calcium levels. High levels of procalcitonin found in blood tests can indicate that a patient has bacterial sepsis, and so, researchers have theorized that LRTI patients with low levels of the protein may be suffering from viral rather than bacterial infections. The study will look at patients 18 years of age and older and who have suspected LRTIs and low blood levels of procalcitonin, and blood tests will be done using the VIDAS® BRAHMS PCT™ test developed by bioMérieux. Up to 420 patients will then be randomized to receive either a 5-day regimen of the oral antibiotic azithromycin or a placebo.

If researchers find no significant difference in improvement rates between the treatment groups, this will demonstrate how low procalcitonin levels could be used to identify patients who do not require antibiotic treatment. On the other hand, if the volunteers given antibiotics respond to treatment better than those given a placebo, this will indicate that procalcitonin should not be used as a biomarker when prescribing antibiotics for LRTIs.

“Healthcare providers and patients benefit from precise diagnostic tests to guide treatment decisions,” said NIAID Director Anthony S. Fauci, MD, in the press release. “An effective biomarker for confirming that a lower respiratory tract infection is viral and thus not treatable with antibiotics would be a significant development in our collective efforts to reduce inappropriate use of antibiotics and combat antimicrobial resistance.”