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Improving Antibiotic Stewardship Through Better Diagnostics

Amesh A. Adalja, MD, FACP, FACEP, May 15, 2015

A lynchpin in optimizing judicious use of antibiotics is minimizing the uncertainty providers have when determining whether a patient has a bacterial or viral infection. While multiplex PCR viral testing is increasingly available and very useful, prolonged turn-around-times associated with these tests and the possibility of bacterial and viral co-infections limit their impact. 

Procalcitonin, a biomarker whose elevation is specific for bacterial infection, is an attractive means to improve antibiotic prescribing. A recent study published in the Journal of Infectious Diseases assesses the ability of this biomarker to influence antibiotic stewardship.

Physicians Act on Results

In this randomized controlled trial, Branche and colleagues at the University of Rochester enrolled 300 patients with lower respiratory tract infections within 24 hours of admission. Patients were randomized to one of two groups, one of which received standard care and the other which had results of procalcitonin as well as multiplex PCR pathogen testing available in the medical record coupled to a treatment algorithm based on those results.  

The primary outcome of the study was the impact of testing results on antibiotic exposure and no significant difference was found between groups, though 42% had viral infection identified and 80% had low procalcitonin levels. Subgroup analysis, however, on those with the positive viral assays results and low procalcitonin levels revealed that physicians were less likely to discharge patients on antibiotics and more likely to shorten duration of antibiotics compared to the control group. Influenza A was the most common virus identified. 

Better Tools = Better Management

This study, though it failed to meet its primary outcome, suggests that when physicians are empowered with tools to increase their confidence in a diagnosis they will tend to take the appropriate action. While it is well established that physicians often know when they are dealing with a viral infection, there is a tendency to nevertheless prescribe antibiotics for myriad reasons, which include patient expectation and a level of uncertainty in their diagnosis. However as the march of antibiotic resistance continues and threatens the practice of modern medicine, it has become imperative that more judicious use of antibiotics be practiced. Coupling procalcitonin to viral testing is likely to become an essential tool in that endeavor. 



Branche AR, Walsh EE, Vargas R, et al. Serum procalcitonin and viral testing to guide antibiotic use for respiratory infection in hospitalized adults: a randomized controlled trial. J Infect Dis 2015. Accessed May 13, 2015