Volatile biomarkers of Pseudomonas aeruginosa in cystic fibrosis and noncystic fibrosis bronchiectasis

Aims: The purpose of this study was to determine whether volatile organic compounds specific to Pseudomonas aeruginosa could be detected in clinical sputum specimens. Methods and Results: Patients were recruited from specialist bronchiectasis and cystic fibrosis clinics. The gold standard for diagnosing Ps. aeruginosa infection was a positive sputum culture. About 72 sputum headspace samples taken from patients at risk of or known to have prior Ps. aeruginosa infection were analysed by solid phase micro-extraction mass spectrometry. 2-nonanone was a marker in Ps. aeruginosa in sputum headspace gas with sensitivity of 72% and specificity of 88%. A combination of volatile compounds, a sputum library of 17 compounds with 2-nonanone, increased sensitivity in the detection of Ps. aeruginosa to 91% with specificity of 88%. Conclusions: In contrast to the 48-hour turnaround for classical microbiological culture, these results were available within 1-2 h. These data demonstrate the potential for rapid and accurate diagnosis of Ps. aeruginosa infection from sputum samples. Significance and impact of the study: 2-Nonanone is a compound requiring further study in the exhaled breath as it may improve diagnostic of Ps. aeruginosa infection when combined with other reported volatile markers.