Diffuse reflectance infrared fourier transform spectroscopic (DRIFTS) investigation of E.coli, Staphylococcus aureus and Candida albicans

Abstract

The present study consists of a refined method for obtaining Diffuse Reflectance Infrared Fourier Transform Spectroscopic (DRIFTS) data for biological samples in the mid infrared region (4000 - 600 cm sup(-1)). The biological cells used in the study included identified clinical strains of E. coli (Gram negative bacterium), Staphylococcus aureus (Gram positive bacterium) and Candida albicans (yeast). The method for obtaining DRIFTS data is described herein, which may be useful for studying the biochemical composition of microbial cells as well as for species-specific identification. The raw spectrum for each culture was treated using various algorithms (Kubelka Munk algorithm and Savitzky-Golay algorithm) and converted into its second derivative (2D). Hierarchical cluster analysis of 2D data, using Ward's algorithm produced dendrogram, which was distinct for each strain under study. Principal component analysis provided clusters of groups used in the study