RT Journal Article SR Electronic T1 An alternative method to the infection detection for differentiation of 3 and 4 MRGN germs by use of GC IMS JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP OA4993 DO 10.1183/13993003.congress-2016.OA4993 VO 48 IS suppl 60 A1 Gunther Becher A1 Roman Purkhart A1 Tobias Raessler A1 Werner Schueler A1 Claus Steppert YR 2016 UL http://erj.ersjournals.com/content/48/suppl_60/OA4993.abstract AB Introduction: Due to the increasing number of multi-resistant germs rapid bacterial tests are needed. Bacteria release volatile markers (VOC) during growth, which can be detected by spectrometry. The aim of the study was to prove the differentiation of 3 or 4MRGN subtypes by GC-IMS.Methods: Headspaces from bacterial liquid cultures were analysed by GC-IMS. The following different bacteria and strains were used to match the realistic clinical questions: Pseudomonas aerug. (7), E. coli, Enterobacter, Klebsiella, Citrobacter, each known as 3 MRGN or 4 MRGN.Using cluster analysis by support vector machine the peaks were detected and compared each other by clustering. Sensitivity and specifity of differentiation was evaluated by Leave-One-Out cross validation method.Results: In comparison of Pseudomonas- to control-media were identified up to 900 different clusters of VOC. i.e. different chemical ions of in headspace of cultures. At least up to 5 were needed to differentiate 3 out of 4 MRGN. The sensitivity for discrimination of bacterial growth in itself was 100%. For the other germs significant clusters as well were identifiedFig. 1: Differentiation of Ps. aerug. 3- (73) & 4-MRGN (74) in comparison to control (1) using 3 Clusters out of 678.Summary: Subtypes of bacteria were possible to differentiate by detection of VOCs. This rapid screening of bacterial growth may help for fast tests and cost saving.