Testing for procalcitonin, a blood biomarker that is increased in people with a bacterial infection, could help physicians more quickly and effectively determine whether patients need antibiotics. Knowing that would ultimately reduce the rate of unnecessary antibiotic use, according to a new study from Duke Health and four other U.S. sites.
This study, published December 13 in The Lancet Infectious Diseases, looked at patients with low likelihood of bacterial lower respiratory tract infections and a low concentration of procalcitonin (which tends to be low in patients without a bacterial infection). The authors hypothesized that patients with low procalcitonin levels are unlikely to benefit from antibiotics – specifically, azithromycin.
While placebo was inferior to azithromycin at day five of the study, there were no differences in clinical improvement rates between the two groups at days 11 and 28 of the study. The antibiotic-treated group also experienced higher rates of side effects such as abdominal pain.
The study also sought to determine why azithromycin was better than placebo at day five. Their findings suggested it was the anti-inflammatory (rather than the antibiotic) properties of azithromycin that made the difference. However, distinguishing between these two possibilities can be challenging.
According to Ephraim Tsalik, M.D., Ph.D., adjunct associate professor in the Department of Medicine at the Duke University School of Medicine, and vice president and chief scientific officer of infectious disease at Danaher Diagnostics, “if a clinician is treating a patient with chronic underlying health problems, they might not be willing to withhold antibiotics, even if the procalcitonin level is low, but if the patient is otherwise healthy, or if the decision to treat with antibiotics is not an obvious one, the test may be helpful in making that determination.”
“If a young, relatively healthy patient is willing to forgo a possible benefit at day five by avoiding antibiotic use, they also avert any antibiotic-related side effects, avert disruptions to their microbiome, and help lower the chances of developing antibiotic resistant infections,” Tsalik said.