S23 A comparative study of polymicrobial diversity in CF and non-CF bronchiectasis

Abstract

Methods Adult patients were recruited from specialist bronchiectasis and Cystic Fibrosis clinics. The gold standard for diagnosing P. aeruginosa infection was positive sputum cultures. 72 sputum samples were analysed. A sputum sample was kept in a glass vial with a cap containing septum. The septum was pierced with a solid phase microextraction (SPME) fibre allowing sampling of the headspace for 50 min at 378C before transferring the fibre into gas chromatography mass spectrometry. AnalyzerPro software (automated peak capture software) and manual identification were used to identify relevant to P. aeruginosa specific compounds in the headspace of sputum. Results 32 samples grew P. aeruginosa either on its own or mixed with other species. 2-nonanone was a marker of P. aeruginosa in sputum headspace gas with sensitivity of 72% and specificity of 88%. Cyanide was not detected. However, a combination of manually identified 2-nonanone with 17 other volatile compounds as identified by AnalyzerPro, increased sensitivity in detection of P. aeruginosa to 91% with specificity of 88%. Conclusion Optimal sampling and capture protocols still need refinement: we were unable to detect the prior noted biomarker Cyanide. These data however demonstrate the potential for rapid and accurate diagnosis of P. aeruginosa infection from sputum samples. In contrast to the 48+ hour turnaround for standard microbiological culture, these results were available within 1e2 h. It also provides a library of compounds as targets to validate in a future study of breath testing. Introduction Lung Clearance Index (LCI) is a measure of lung gas mixing derived from the Multiple Breath Washout (MBW) test. We present LCI, FEV 1 and CT data from the Run-In Study, a longitudinal study in preparation for a multi-dose trial of nebulised gene therapy for CF. Methods MBW, spirometry and low-dose HRCT chest were performed as part of the first Run-In Study visit. LCI was reported as the mean result from at least two technically acceptable sulphur hexafluoride MBW tests performed using a modified Innocor gas analyser. Spirometry was performed to ERS standards. CT scans were assessed by two independent radiologists for extent and severity of bronchiectasis, wall thickening, presence of small and large airway plugs, and gas trapping. Results 191 patients attended visit 1, mean (range) age 22.6 (10e59.1) years. Validated LCI, FEV 1 and CT results were available for 167, 191 and 150 patients, respectively. Mean (SD) FEV 1 was 72 (19)% predicted. Mean (SD) LCI was 10.7 (2.7), with mean intravisit coefficient of variation of 4.9%. LCI correlated negatively with FEV 1 (r¼À0.68, p<0.001), but was abnormally elevated in 72% of participants with normal FEV 1 (see Abstract S22 Figure 1; triangles indicate FEV 1 >80% and LCI >7.5). 95% CI for LCI in normal subjects 5.9 to 7.5. Both FEV 1 and LCI correlated with all CT measures (p<0.001), most strongly with extent of bronchiectasis. LCI correlated better than FEV 1 with extent of bronchiectasis, r¼0.72 (p<0.001) vs r¼À0.61...

Bronchiectasis: literature review for preparation of 2024 clinical guidelines

“…P. aeruginosa также нередко обнаруживается у взрослых пациентов с БЭ немуковисцидозной этиологии -в 12-43 % случаев [11,22]. Колонизация этим микроорганизмом сопровождается более низкими показателями легочной функции, более выраженными симптомами, качеством жизни, частыми госпитализациями и худшим прогнозом по сравнению с пациентами той же группы, у которых данный возбудитель не высевался [23].…”