Richard Y Kao
University of Hong Kong, Hong Kong
Title: Food ingredients modulating the expression of virulence factors in bacteria
Biography
Biography: Richard Y Kao
Abstract
Statement of the Problem: Disease-causing properties (virulence) of microbial pathogens are greatly influenced by environmental factors such as temperature, pH, and food ingredients like carbohydrates. As human bodies are inhabited by a number of opportunistic pathogens, factors modulating the virulence of these potential disease-causing bacteria may have important health consequences. We have developed reporter systems in bacteria for evaluating the virulence modulating properties of various agents including common food ingredients.
Methodology & Theoretical Orientation: We have constructed gfp-luxABCDE dual-reporter plasmids with selected promoters from bacterial virulence-associated genes. The plasmids were introduced into bacteria to establish a gfp-lux based multiplex promoter reporter platform for monitoring bacterial virulence gene expressions in real time to identify factors that may modulate virulence factors expression. We have selected a number of common food ingredients and tested these ingredients in our multiplex promoter reporter platform to evaluate their virulence modulating properties. Virulence gene expression in bacteria was monitored by luminescence signals detected with an IVIS Spectrum In Vivo Imaging System (PerkinElmer).
Findings: We have profiled the virulence modulating activities of common food ingredients on 9 bacterial virulence gene promoters, namely promoters from genes involved in the production of α-toxin, Panton-Valentine leukotoxin, phenol-soluble modulins, Protein A, Extracellular Adhesion Protein, fibronectin binding protein A, fibronectin binding protein B, clumping factors A, and capsular polysaccharide. The tested virulence factors are important for the establishment of bacterial infections in humans.
Conclusion & Significance: Microbial virulence is an overlooked factor while considering food ingredients and nutritional supplements for healthy individuals or patients with special needs. Our study has provided an evidence-based scientific platform for the effective evaluation of various food substances that may modulate the virulence of opportunistic pathogens residing in humans.