Lipidomic approach to identify Escherichia coli and Shigella spp. by matrix-assisted laser desorption/ionization mass spectrometry

Arendowski, Adrian

Lipidomic approach to identify Escherichia coli and Shigella spp. by matrix-assisted laser desorption/ionization mass spectrometry

Abstract

Purpose: Escherichia coli and Shigella species due to their very closely related, are difficult to distinguish by classical methods such as phenotyping, 16S rRNA sequencing or protein profiling using matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). The paper presents the possibility of identifying E. coli, S. flexneri, S. sonnei and S. boydii by adding to the Bruker Biotyper database reference spectra of lipid profiles recorded with the MALDI MS technique in the positive mode. Materials/methods: Lipid extracts were made from cultured E. coli, S. flexneri, S. sonnei and S. boydii using the Bligh & Dyer protocol. MALDI MS spectra in positive ion mode were performed for the extracts. Reference spectra were created from 30 spectra for each bacterium and added to the Bruker Biotyper database. Results: Identification of bacteria based on lipid profiles in the Biotyper database gave correct results with scores above 2.49. Statistical analysis of the results by Partial Least Squares-Discriminant Analysis (PLS-DA) showed that it is possible to correctly differentiate the microorganisms studied using the lipidomic approach. A panel of six m/z values was proposed for which the value of the area under the ROC curve is 1, thus enabling the identification of E. coli and S. flexneri with 100% accuracy. Conclusions: Identification of bacteria from lipid fingerprints obtained by the MALDI MS technique is possible and may become a useful tool in the future, especially for microorganisms that are difficult to distinguish by other methods.

Keywords

Bacteria Identification Lipids MALDI Mass spectrometry

Citation

Arendowski A. Lipidomic approach to identify Escherichia coli and Shigella spp. by matrix-assisted laser desorption/ionization mass spectrometry. Advances in Medical Sciences. 2024;69(2):238–247. doi: 10.1016/j.advms.2024.04.005