Volatile organic compound (VOC) analysis in exhaled breath is proposed as a non-invasive method to detect respiratory infections in cystic fibrosis patients. Since polymicrobial infections are common, we assessed whether we could distinguish Pseudomonas aeruginosa and Aspergillus fumigatus mono- and co-cultures using the VOC emissions. We took headspace samples of P. aeruginosa, A. fumigatus and co-cultures at 16, 24 and 48 h after inoculation, in which VOCs were identified by thermal desorption combined with gas chromatography - mass spectrometry. Using multivariate analysis by Partial Least Squares Discriminant Analysis we found distinct VOC biomarker combinations for mono- and co-cultures at each sampling time point, showing that there is an interaction between the two pathogens, with P. aeruginosa dominating the co-culture at 48 h. Furthermore, time-independent VOC biomarker combinations were also obtained to predict correct identification of P. aeruginosa and A. fumigatus in mono-culture and in co-culture. This study shows that the VOC combinations in P. aeruginosa and A. fumigatus co-microbial environment are different from those released by these pathogens in mono-culture. Using advanced data analysis techniques such as PLS-DA, time-independent pathogen specific biomarker combinations can be generated that may help to detect mixed respiratory infections in exhaled breath of cystic fibrosis patients.

Aspergillus fumigatus, co-culture, cystic fibrosis, GC-MS, partial least squares discriminant analysis, Pseudomonas aeruginosa, volatile biomarker combination
dx.doi.org/10.1088/1752-7155/10/1/016002, hdl.handle.net/1765/90560
Journal of Breath Research
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Department of Medical Microbiology and Infectious Diseases

Neerincx, A.H, Geurts, B.P, Habets, M.F.J, Booij, J.A, Van Loon, J, Jansen, J.J, … Kluijtmans, L.A.J. (2016). Identification of Pseudomonas aeruginosa and Aspergillus fumigatus mono- and co-cultures based on volatile biomarker combinations. Journal of Breath Research, 10(1). doi:10.1088/1752-7155/10/1/016002