Procalcitonin Shows Promise in Antibiotic Therapy

Procalcitonin, a biomarker blood infection, traditionally has been used to gauge the likelihood that a patient has a bacterial infection; it also helps determine if an infection is clearing, as its levels decrease during infection recovery. Because it’s a proven marker of a host’s response to bacterial infection, scientists have been working on utilizing procalcitonin in antibiotic treatment in order to reduce patients’ unnecessary exposure to antibiotics. Procalcitonin was approved by the US Food and Drug Administration earlier this year for use in antibiotic treatment.

A team led by Swiss scientists conducted a meta-analysis of 6,708 patients in a total of 26 randomized controlled trials in order to determine the safety and efficacy of procalcitonin-guided treatment for acute respiratory infections. The study, published in The Lancet, revealed that the death rate for patients receiving procalcitonin-guided treatments was significantly lower (9%) after 30 days than the death rate for patients who did not receive procalcitonin (10%). Patients who received procalcitonin guidance also averaged 2 to 4 days fewer on antibiotics and suffered fewer antibiotic-related side effects.

Because antibiotic overuse is an established problem, and responsible health care providers and patients look to minimize the use of antibiotics whenever possible, the potential use of procalcitonin in antibiotic therapy—including for infections other than respiratory ones—is an intriguing development.

“It...allows [us] to individualize duration of treatment based on the resolution of illness,” Philipp Schuetz, MD, MPH, a professor at Kantonsspital Aarau and the University of Basel in Switzerland and the lead author of the study, told Contagion^®. “While physicians used to give fixed antibiotic courses for respiratory infections, the biomarker approach allows [us] to personalize these durations to severity of infection and patient response.”

One of the factors contributing to antibiotic overuse is that it can be extremely difficult, if not impossible, to determine if an infection is caused by bacteria or a virus. According to the study authors, more than 40% of respiratory infections are viral in nature—yet, perhaps out of an abundance of caution, antibiotics are likely to be prescribed in these cases. Antibiotics normally are the right choice for infections caused by bacteria, but taking antibiotics for too long a period—particularly in the case of patients who have bacterial infections and sepsis—can lead to the rise of pathogens resistant to a variety of drugs. Thus, procalcitonin may be useful in helping physicians determine the best course of treatment and avoid contributing to the problem of overuse.

For all of its promise, however, procalcitonin is not a panacea. Uncertainty remains regarding the specific concentrations of procalcitonin that can be safely used in treatment plans, and there is little data available about its safety in the pediatric population. “Generally, physicians have been looking for the perfect sepsis marker that would allow 100% differentiation between bacterial infection and viral inflammation,” Dr. Schuetz said. “I think we need to accept that due to the heterogeneity of underlying infections causing sepsis, and the severity of these infections, we may never find this perfect marker. PCT, however, is a good start [in the quest to move] towards individualized antibiotic treatment decisions. [It] is not a perfect infection marker and should not be viewed as a new gold standard for [treating] infection but, rather, an additional tool that helps physicians to make more rational, objective decisions regarding antibiotics.”

Because questions about procalcitonin remain, Dr. Schuetz asserts that health care providers should always conduct thorough clinical exams and rely on additional testing when determining whether and how to prescribe procalcitonin-guided antibiotic therapy for any kind of infection.

Laurie Saloman, MS, is a health writer with more than 20 years of experience working for both consumer and physician-focused publications. She is a graduate of Brandeis University and the Medill School of Journalism at Northwestern University. She lives in New Jersey with her family.