Influence of the sample preparation method in discriminating Candida spp. Using ATR-FTIR spectroscopy

Savithri Pebotuwa, Kamila Kochan, Anton Peleg, Bayden R. Wood, Philip Heraud

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)

Abstract

Several studies have investigated the capacity of ATR-FTIR spectroscopy for fungal species discrimination. However, preparation methods vary among studies. This study aims to ascertain the effect of sample preparation on the discriminatory capacity of ATR-FTIR spectroscopy. Candida species were streaked to obtain colonies and spectra were collected from each preparation type, which included: (a) untreated colonies being directly transferred to the ATR crystal, (b) following washing and (c) following 24-h fixation in formalin. Spectra were pre-processed and principal component analysis (PCA) and K-means cluster analysis (KMC) were performed. Results showed that there was a clear discrimination between preparation types. Groups of spectra from untreated and washed isolates clustered separately due to intense protein, DNA and polysaccharide bands, whilst fixed spectra clustered separately due to intense polysaccharide bands. This signified that sample preparation had influenced the chemical composition of samples. Nevertheless, across preparation types, significant species discrimination was observed, and the polysaccharide (1200-900 cm−1) region was a common critical marker for species discrimination. However, different discriminatory marker bands were observed across preparation methods. Thus, sample preparation appears to influence the chemical composition of Candida samples; however, does not seem to significantly impact the species discrimination potential for ATR-FTIR spectroscopy.

Original languageEnglish
Article number1551
Number of pages11
JournalMolecules
Volume25
Issue number7
DOIs
Publication statusPublished - 28 Mar 2020

Keywords

  • ATR-FTIR spectroscopy
  • Candida
  • Fungi
  • PCA

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