Rapid Classification of Single Bacterium Based on Backscattering Microscopic Spectrum—A Pilot Study

Cheng Wang,Songlin Zhuang,Minghui Chen,Bin Liu,Xunbin Wei,Qing Liu,Sen Li,Dawei Zhang,Gang Zheng

doi:10.3389/fphy.2020.00097

Abstract

Rapid detection of foodborne pathogens is one of the most effective ways to solve food safety problems. To achieve rapid and noninvasive detection and classification of foodborne pathogens, we modified a fiber confocal backscattering micro-spectral system to suit an extremely small biological sample, that is, a bacterium. This system offers single-bacterium level, label-free, convenient, and environmentally friendly characterization. Three categories of common foodborne pathogens (Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus) were measured. The scattering spectrum ranging from 450 to 900 nm was selected, and by the model of principal component analysis (PCA) and error back propagation algorithm of back propagation neural network (BPNN), the backscattering microscopic spectra of three categories of pathogens were dimensionality reduced, identified and classified. The results showed that the identification accuracy of three categories of pathogens was above 90%, under neutral, acidic and alkaline culturing conditions，respectively. The preliminary results demonstrated the feasibility of using confocal backscattering microscopic spectra combined with PCA and BPNN algorithm to identify and classify single bacterium in a rapid, noninvasive, and label-free manner.

Highlights

At present, foodborne illness poses a serious public health threat
The backscattering micro-spectra of S. typhimurium, E. coli, and S. aureus that were cultured under neutral condition, were measured using the modified fiber confocal backscattering microspectrometer (FCBS)
Spectral data of 150 samples were collected as prediction set samples, 1–50, 51–100, and 101–150 cases were S. typhimurium, E. coli, and S. aureus spectral data, respectively

Summary

Introduction

Foodborne illness poses a serious public health threat. Foodborne pathogens are the major cause of foodborne illness [1]. According to World Health Organization (WHO) estimates, pathogenic microorganisms are responsible for 70% of the world’s foodborne disease patients [2]. There are 1.5 billion diarrhea cases caused by biocontamination of food every year, of which about 3 million resulted in death among children

Methods

Results

Conclusion