Novel tool could discriminate bacterial from non-bacterial respiratory infection

Recent findings published in Scientific Reports have identified 11 genetic markers in the blood that could potentially allow physicians to distinguish between bacterial and non-bacterial lower respiratory tract infection (LRTI).

This newly developed method could be utilized to help avoid prescribing patients antibiotics when the infection causing their illness is not bacterial, which could potentially help combat the increasing threat of antibiotic resistance.

Lead author of this study and Professor at the University of Rochester Medical Centre (NY, USA), Ann Falsey, explained the significance of these findings: “It’s extremely difficult to interpret what’s causing a respiratory tract infection, especially in very ill patients who come to the hospital with a high fever, cough, shortness of breath and other concerning symptoms.”

“My goal is to develop a tool that physicians can use to rule out a bacterial infection with enough certainty that they are comfortable, and their patients are comfortable, foregoing an antibiotic.”

In this study led by Falsey, researchers used peripheral blood gene expression strategies to identify whether there are certain genes that discriminate infectious agents in those with LRTI.

Member of the Respiratory Pathogens Research Center (NY, USA), Thomas Mariani, stated: “Our genes react differently to a virus than they do to bacteria. Rather than trying to detect the specific organism that’s making an individual sick, we’re using genetic data to help us determine what’s affecting the patient and when an antibiotic is appropriate or not.”

Microbiologic tests were performed on blood samples taken from the patients and gene expression was measured using RNASeq and qPCR. Of the 94 subjects that were enrolled in the study, 41 and 53 were confirmed to have bacterial and non-bacterial LRTI, respectively.

By genetic and statistical analysis, 11 genes were demonstrated to have significant differences in expression between bacterial and non-bacterial infection. Studies suggested that this novel method was able to correctly identify bacterial infection 80–90% of the time.

Although these findings are promising, researchers suggest that further research is still needed owing to the small sample size tested in this study. They also suggest that the genetic markers identified here may not be universal to be all patients.

However, with additional study, this tool could be a promising tool for distinguishing bacterial and non-bacterial infection, which so far has proven difficult.

Sources: Bhattacharya S, Rosenberg AF, Peterson DR et al. Transcriptomic Biomarkers to Discriminate Bacterial from Nonbacterial Infection in Adults Hospitalized with Respiratory Illness. Sci. Rep. 7(1), 6548 (2017);


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