Untersuchungen am Trachealaspirat beatmeter Früh- und Reifgeborener zur Infektionsdiagnostik und Prädiktion der Bronchopulmonalen Dysplasie - eine Pilotstudie

Diseases of prematurity such as neonatal infections and bronchopulmonary dysplasia (BPD) are frequent in preterm neonates, resulting from incomplete organ development. Early and late onset neonatal infections are a primary reason for mortality in preterms during the neonatal period. BPD is caused by an inflammatory process that prevents further development of the premature lung, resulting in a chronic pulmonary disease with prolonged need for supplementary oxygen. Early prediction markers for BPD are still lacking. Likewise, valid diagnosis of invasive infection in preterm and term neonates is difficult due to unspecific clinical symptoms. In this project BPD and neonatal infections were investigated by analysing tracheal aspirates of 33 preterm and term neonates, which were collected during routine suctioning of the intubated patients. IL-6 and IFN-γ cytokine concentrations in the tracheal aspirates were measured by immunoassay. Conventional microbiological analysis consisting of gram staining, microscopy and bacterial culture was performed, as well as molecular analysis, which included PCR of 16S-rDNA and separation of the PCR- products by chromatography. Additionally, an electronic nose, a device that senses volatile organic compounds (VOCs) through 32 biopolymer sensors, was utilized. Smellprints were generated according to the detected VOCs. Preterms born before completion of 32 weeks that developed BPD later on did not show higher levels of IL-6 and IFN-γ in their tracheal aspirates when compared to preterms that did not develop BPD. Tracheal aspirate cytokines were also not elevated in patients with signs of systemic infection or detection of bacteria in the tracheal aspirate. Comparison of the different microbiological detection methods showed a high rate of mismatches. In patients that developed BPD, germs were detected significantly more often in the tracheal aspirate when compared to patients that did not develope BPD. The smellprint linear discriminant analysis showed promising results: smellprints from tracheal aspirates of patients with and without subsequent development of BPD differed significantly. Furthermore, smellprints from tracheal aspirates of neonates with laboratory-confirmed bloodstream infection differed significantly from those without infection, regardless of a positive or negative microbiological test result. The application of an electronic nose may prove useful in the prediction of BPD development and diagnosis of neonatal infections. Larger numbers of samples will be needed for further validation of the respective smellprint patterns.