Presentation
4 March 2019 Rapid monitoring of live to dead bacterial cell ratios using the optrode (Conference Presentation)
Fang Ou, Cushla McGoverin, Simon Swift, Frédérique Vanholsbeeck
Author Affiliations +
Abstract
A rapid and easy method for determining the ratio of live to dead bacteria in a sample is valuable in many fields of microbiological and pharmacodynamics studies, and for the monitoring of food safety and public health. Efficient, culture-independent detection of live and dead bacteria can be achieved using differentially staining fluorescent dyes SYTO 9 and propidium iodide (PI). Fluorescence microscopy and flow cytometry have been used extensively for detection of these live/dead cell fluorescence signals, however, both these methods require bulky equipment and are relatively expensive to implement. We are developing a cost-effective and portable fibre-based fluorometer for the accurate measurement of fluorescence signals to determine the proportions of live and dead bacteria present. Escherichia coli suspensions with differing ratios (from 0 to 100%) of live to dead cells were stained with SYTO 9 and PI. Fluorescence spectra were collected from samples using the optrode, which consists of a 473 nm solid state laser, DAQ controlled shutter, photodiode for monitoring the laser power and CCD spectrometer. Three regression techniques (simple SYTO 9/PI intensity ratio, adjusted SYTO 9/PI intensity ratio, and support vector regression (SVR)) were used to analyse the spectra to predict the percentage of live bacteria present in each sample. To date, SVR achieved the best correlation (R^2>0.99, for samples containing 108 bacteria/mL). Preliminary results are promising and show that this method may be extended to a wider concentration range or modified for the calibration of other bacterial species of interest.
Conference Presentation
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Fang Ou, Cushla McGoverin, Simon Swift, and Frédérique Vanholsbeeck "Rapid monitoring of live to dead bacterial cell ratios using the optrode (Conference Presentation)", Proc. SPIE 10881, Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues XVII, 108810Z (4 March 2019); https://doi.org/10.1117/12.2506213
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KEYWORDS
Bacteria

Luminescence

Camera shutters

Data acquisition

Flow cytometry

Fluorometers

Microscopy

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