Identification of bacteria by fatty acid profiling with direct analysis in real time mass spectrometry. (27th September 2015)

• Record Type: Journal Article
• Authors: Cody, Robert B.; McAlpin, Casey R.; Cox, Christopher R.; Jensen, Kirk R.; Voorhees, Kent J.
• Is Part Of: Rapid communications in mass spectrometry. Volume 29:Number 21(2015)
• Page Start: 2007
• Page End: 2012
• Publication Date: 2015-09-27
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.7309
• Languages: English
• ISSNs: 0951-4198

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="rcm7309-sec-0001" sec-type="section"> <title>Rationale</title> <p>Bacterial fatty acid profiling is a well‐established technique for bacterial identification. Current methods involving esterification and gas chromatography/mass spectrometry (GC/MS) or matrix‐assisted laser desorption/ionization (MALDI) analysis are effective, but there are potential benefits to be gained by investigating ambient ionization methods that can provide rapid analysis without derivatization or additional sample handling.</p> </sec> <sec id="rcm7309-sec-0002" sec-type="section"> <title>Methods</title> <p>Lipid extracts from colonies of five Gram‐positive and five Gram‐negative pathogenic bacteria were analyzed by Direct Analysis in Real Time (DART) ionization coupled with a time‐of‐flight mass spectrometer. Fatty acid profiles were obtained from the negative‐ion DART mass spectra without additional derivatization or sample preparation.</p> </sec> <sec id="rcm7309-sec-0003" sec-type="section"> <title>Results</title> <p>Fatty acid profiles obtained from the deprotonated molecules [M – H]<sup>−</sup> were found to be highly species‐specific and reproducible. Leave‐one‐out cross validation (LOOCV) for principal component analysis (PCA) showed 100% correct classification accuracy.</p> </sec> <sec id="rcm7309-sec-0004" sec-type="section"> <title>Conclusions</title> <p>The results of this preliminary feasibility study show good precision and accuracy, and the fatty acid patterns are clearly distinctive for each of the ten species examined. The speed and ease of analysis and the high classification accuracy for this initial study indicate that DART is an effective method for bacterial fatty acid profiling. Copyright © 2015 John Wiley & Sons, Ltd.</p> </sec> </abstract>