Rapid Evaporative Ionisation Mass Spectrometry (REIMS) Provides Accurate Direct from Culture Species Identification within the Genus Candida

Abstract

Members of the genus Candida, such as C. albicans and C. parapsilosis, are important human pathogens. Other members of this genus, previously believed to carry minimal disease risk, are increasingly recognised as important human pathogens, particularly because of variations in susceptibilities to widely used anti-fungal agents. Thus, rapid and accurate identification of clinical Candida isolates is fundamental in ensuring timely and effective treatments are delivered. Rapid Evaporative Ionisation Mass Spectrometry (REIMS) has previously been shown to provide a high-throughput platform for the rapid and accurate identification of bacterial and fungal isolates. In comparison to commercially available matrix assisted laser desorption ionisation time of flight mass spectrometry (MALDI-ToF), REIMS based methods require no preparative steps nor time-consuming cell extractions. Here, we report on the ability of REIMS-based analysis to rapidly and accurately identify 153 clinical Candida isolates to species level. Both handheld bipolar REIMS and high-throughput REIMS platforms showed high levels of species classification accuracy, with 96% and 100% of isolates classified correctly to species level respectively. In addition, significantly different (FDR corrected P value < 0.05) lipids within the 600 to 1000 m/z mass range were identified, which could act as species-specific biomarkers in complex microbial communities.

Evaluation of Direct from Sample Metabolomics of Human Feces Using Rapid Evaporative Ionization Mass Spectrometry

“…Initial applications of REIMS utilised electrosurgical hand-pieces, such as electrical diathermy surgical devices and bipolar surgical forceps, to direct the electrical current and aspirate the analyte-containing vapour to a mass spectrometer 20 . Recent advances have adapted REIMS to a modified liquid handling platform, which allows for the high-throughput (approximately 3-4,000 samples per 24 hour period) semi-automated analysis of samples with minimal user input 21,22 .…”

Effect of Electrode Geometry on the Classification Performance of Rapid Evaporative Ionization Mass Spectrometric (REIMS) Bacterial Identification

“…Importantly, this high-throughput platform was shown to possess the same degree of analytical discrimination as the bipolar forceps REIMS approach, with substantially reduced intra-sample variability [ 10 ]. In addition, it was shown to be superior to the hand-held bipolar forceps in the species-level classification of eight Candida species, providing perfect accuracy [ 11 ].…”

Meet interesting abbreviations in clinical mass spectrometry: from compound classification by REIMS to multimodal and mass spectrometry imaging (MSI)

“…REIMS was also soon identified as a prospective tool for bacterial metabolomics (Strittmatter et al, 2013). The original work was extended to yeasts and fungi (Bolt et al, 2016;Cameron et al, 2016), although it is still being focused rather to a statistic approach and not to the actual structure identification of microbial metabolites (Strittmatter et al, 2014).…”