Differenzierung von Escherichia coli und Pseudomonas aeruginosa mittels Ionenmobilitätsspektrometrie

Abstract

A quick and reliable alternative technology to standard microbiological testing could be the detection of volatile organic compounds (VOC) using multi-capillary column-ion mobility spectrometry (MCC-IMS). The approach to differentiate bacteria and fungi has already been described before. Using a complex fluid medium we first analysed the growth of two human pathogenic reference strains of Escherichia coli and Pseudomonas aeruginosa and generated growth curves. Knowing the time line of the different growth phases we analysed the headspace over the two bacteria at four given times to determine if it is possible to differentiate between the two bacteria and how the VOCs develop over the time. Secondary we analysed clinical samples in order to see whether the the results of the reference strains could be transferred to other strains of the same species. Overall we found 19 VOCs that occurred in our measurements. Most of them had their peak in the late logarithmic or static growth phases. There were 13 VOCs that only appeared over one species, so these VOCs made it possible to differentiate between the two bacteria. There were six VOCs changing only over Escherichia coli and seven VOCs changing only over Pseudomonas aeruginosa. There were no differences in the occurrence of VOCs over the reference strain compared with the clinical isolates of one species.