Spectroscopy method can detect bacterial infection in exhaled breath
Although ethylene is best known as a plant hormone, humans also produce it as consequence of oxidative stress caused, for example, by UV radiation from sun exposure. Knowing this, an international team of researchers at Radboud University (Nijmegen, Netherlands) and collaborators found that ethylene is produced during inflammation and quickly released in exhaled breath as a biomarker of bacterial infection, thus having important clinical implications.
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Traces of ethylene were detected by laser spectroscopy as part of the systemic inflammatory response to bacterial infection, both in isolated blood leukocytes as well as in controlled experiments with healthy volunteers. Specialists from the Radboud Trace Gas Facility and several medical groups from Radboud University Medical Center, Johns Hopkins University (Baltimore, MD), and Imperial College London showed how ethylene is being formed as a product of the so-called respiratory burst. This is a key component of the immune system, when the body releases reactive oxygen species to fight against invading bacteria. Not only the targeted bacteria suffer from this, the human tissue gets hurt as well. Oxidation of lipids in the cell walls result in ethylene emanation.
"Our results highlight that ethylene release is an early biomarker of bacterial infection," explains Simona Cristescu from Radboud University’s Institute for Molecules and Materials. "In humans, ethylene was detected at least half an hour earlier than the increase of blood levels of inflammatory cytokines and stress-related hormones. For patients in intensive care, this could mean a difference between life and death."
"The first possible application I see is continuous monitoring of patients that are on artificial respiration," says Laurent Paardekooper, a researcher at Radboud University Medical Center and first author of the paper describing the work. "These people have an increased risk of dangerous infections and because their breath is already going through a machine, it is easy to monitor it for ethylene."
According to Cristescu, taking breath samples for analysis is very easy for both patients and staff. Sensor Sense, a spinoff company of Radboud University's Trace Gas Facility, markets a small device that hospitals can use for real-time analysis of exhaled ethylene.
Full details of the work appear in the journal Scientific Reports.