title: Optical Fiber-Based Steady State and Fluorescence Lifetime Spectroscopy for Rapid Identification and Classification of Bacterial Pathogens Directly from Colonies on Agar Plates.
abstract: Fluorescence spectroscopy was examined as a potential technique for identification and classification of bacterial pathogens. Colonies of Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumoniae on agar plates were measured directly using a laboratory spectrofluorimeter coupled with optical fiber. Steady state fluorescence spectra were collected following excitation at 280 nm (tryptophan) and 380 nm (NADH). Results showed that fluorescence lifetime decays of tryptophan at 280 nm excitation from the four organisms were best described with triexponential fit and it reveals the existence of different protein conformation. The emission spectroscopy of the four bacteria at 380 nm excitation (NADH) provided better classification (100% of original grouped cases correctly classified and 98.1% of cross-validated grouped cases correctly classified) than that of 280 nm excitation (tryptophan). Our results demonstrated that optical fiber-based fluorescence identification and classification of bacteria is rapid, easy to perform, and of low cost compared to standard methods.
authors.affiliation: Department of Medical Physics, Anna University, Chennai 600025, India; Department of Medical Physics, Red Sea University, P.O. Box 24, Port Sudan, Sudan.
authors.forename: Fathi
authors.identifier: 0000-0002-0076-8621
authors.initials: F
authors.lastname: Awad
authors.affiliation: Centre for Advanced Studies in Botany, University of Madras, Chennai 600025, India.
authors.forename: Chandrasekaran
authors.initials: C
authors.lastname: Ramprasath
authors.affiliation: Centre for Advanced Studies in Botany, University of Madras, Chennai 600025, India.
authors.forename: Narayanasamy
authors.initials: N
authors.lastname: Mathivanan
authors.affiliation: Department of Medical Physics, Anna University, Chennai 600025, India.
authors.forename: Prakasa Rao
authors.initials: PR
authors.lastname: Aruna
authors.affiliation: Department of Medical Physics, Anna University, Chennai 600025, India.
authors.forename: Singaravelu
authors.identifier: 0000-0002-0994-9445
authors.initials: S
authors.lastname: Ganesan