Fluorescence fingerprints of oral bacteria

Abstract

The rapid detection and identification of microorganisms is one of the most important factors in many cases of ill health. The purpose of this study was to determine the fluorescence characteristics of seven oral bacteria using emission spectra with the aim of distinguishing between the bacteria, and to compare fluorescence imaging methods for the direct assessment of oral bacteria. Fluorescence images of each bacterium were obtained under a 405‐nm light source using a two‐filter system. The emissions of all samples were measured with a fluorescence spectrometer. The complete fluorescence data set collected for each sample employed a three‐dimensional data cube. The differences in the autofluorescence characteristics of the seven oral bacteria were determined by principal components analysis (PCA). The fluorescence images of the oral bacteria varied with the genus and the filter system. The three‐dimensional excitation‐emission matrix fluorescence spectra exhibited distinctive fluorescence features associated with intracellular fluorophores. The seven bacteria could be clearly differentiated on the PCA score plot. The findings of this study indicate that oral bacteria can be identified based on their autofluorescence characteristics. Fluorescence spectroscopy coupled with PCA can be used to detect and classify oral bacteria.

Light and Autofluorescence, Multitasking Features in Living Organisms

“…A study on the red and green fluorescence detected in variable proportions in various microorganisms isolated form the oral cavity has also directed to the conclusion that in dentistry red fluorescence seems to be indicative of the presence of bacteria causing caries [145,146]. A successive study based on the characterization of spectral and tridimensional excitation-emission matrices recorded from different species of oral bacteria has provided specific fluorescence fingerprints in the green-red spectral region for each kind of microorganisms, providing a promising perspective for the development of a user friendly, rapid and relatively low-cost procedures to identify oral microorganisms [147]. The analysis of fluorescence in terms of excitation emission matrices collected in the overall UV-visible spectral range has been also used to characterize eleven kinds of bacteria of clinical interest, valuable for the application translation to the search of possible surface contaminations on hospital equipment [148].…”

Midi-metagenomics: A novel approach for cultivation independent microbial genome reconstruction from environmental samples

“…Depending on the research question it should even be possible to enrich cells expressing certain genes of interest, by using specific mRNA targeting probes instead of rRNA probes. Last but not least, autofluorescence spectra caused by diverse membrane proteins in different organisms 25 may be exploited to enrich or deplete cells with specific functional properties. In this regard, midi-metagenomics has the added potential to specially target and analyze specific organisms, functions or metabolic traits of interest within complex communities, regardless of actual abundance in the sample.…”

“…Possible strategies for selectively fractionating a complex community into distinct subpopulations via FACS are manifold and can be based on phylogenetic, physiological or morphological properties of the target organisms 15 , e.g., FISH staining using rRNA or mRNA probes 2,23,24 , autofluorescence detection 25 or simply cell size and complexity 26 . In order to improve MAG reconstruction by Since the resulting read datasets represent different enrichments based on the same original community, they are optimal for co-assembly as well as co-abundance variation-based binning approaches.…”

Smartphone-based autofluorescence imaging to detect bacterial species on laboratory surfaces

“…A 405 nm LED was chosen due to its ability to excite bacterial species. [18][19][20] More specifically, porphyrins produced by bacteria are commonly used as a fluorescent biomarker that gets optimally excited by the 405 nm LED. 10,21,22 This 405 nm excitation should be specific to bacteria but not to tryptophan in proteins and nicotinamide adenine dinucleotide (NAD) (all excited by deep UV from 260-280 nm).…”