Boomgaard, M. van den (Maartje) (2014) Determinatie van Non-tuberculeuze mycobacteriën met Matrix Assisted Laser Desorption Ionisation – Time Of Flight Mass Spectometry (MALDI-TOF MS). thesis, Medicine.
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Abstract
Non tuberculous mycobacteria (NTM) are environmental bacteria often isolated from soil and water. NTM have a big difference in clinical relevance. Some species cause clinical relevant infections, while others are regarded as culture contamination. That’s why quick and accurate identification is important. Current determination methods are based on biochemical phenotyping and DNA sequencing. These methods are time consuming and expensive. This research explores the determination of NTM with Matrix Assisted Laser Desorption Ionisation-Time of Flight Mass Spectrometry (MALDI-TOF MS). This new determination method caused a revolution in bacterial determination because of the accurate determination combined with increased speed and low costs. We identified 122 isolates of 27 different species with MALDI-TOF MS, GenoType Mycobacterium Assay (HAIN Lifescience) and sequencing with 16S and ITS targets. MALDI-TOF MS analysis correctly identified 92% of the isolates on liquid media and 91% of the isolates on solid media. Of those 75% (liquid media) and 67% (solid media) had a score >2,000, indicating secure species identification. This combined with the low costs (€47,12 (MALDI-TOF MS) versus €135,41 (GenoType) en €376,54 (sequencing)) and quick results (daily versus weekly) makes MALDI-TOF MS an attractive identification method for NTM. Though prospective research with clinical isolates is necessary before making this a routine identification method. In addition we investigated the optimal conditions for MALDI-TOF MS analysis. We found significant influence for the amount of mass spectra in the database used and the age of the colonies before analysing. Neither the protein extraction protocol or consumables used had an influence on the results.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Klein, Dhr. Dr. J.J. |
| Supervisor name: | Mulder, Dhr. Dr. L. and Koehorst, Dhr. N. and Leussenkamp-Hummelink, Mw. R. and Laboratorium Microbiologie Twente Achterhoek |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 10:48 |
| Last Modified: | 25 Jun 2020 10:48 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/940 |
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