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The Gene and Linda Voiland School of Chemical Engineering and Bioengineering

Research of Nehal I. Abu-Lail

Profiling Pathogens using a Physiochemical Approach

⬅ Back to Dr. Abu-Lail’s List of Research Projects

Problems

  1. Profiling pathogens on genetic basis is labor and cost intensive
  2. Genes evolve kinetically and change with stress

Goal

Complement genetic approaches with physiochemical means to profile pathogens.

Impact

Pathogens can be distinguished from nonpathogens accurately.

Figure

Environmental media, bacteria, substrate
Factors that affect bacterial adhesion
Graph and close-up of biofilm
Virulence-adherence relationship and biofilms on AFM cantilever

Electrophoresis measurements

Graph showing electrophoretic mobility as it relates to the concentration of bulk ions
Electrophoretic mobility as a function of ionic strength

Contact angles' measurements

Equation with indentation depth, applied loading force, elastic moduli, Poisson's ratio of bacteria, and radius of indenter
Hertz model of contact mechanics
Graph with the indentation of virulent strains 51776 and EGDe, avirulent strains 15313 and HCC25, modified Hertz model, classic Hertz model
Hertz model of AFM data
Equation with variables for Force, Separation distance, temperature and Boltzmann constant
Steric model

graph showing distance and corresponding force for virulent strains 51776 and EGDe, avirulent strains 15313 and HCC25, and Steric model
Steric model fits to AFM data

Assays

  • Multidrug resistance (MDR) assay
  • Minimal inhibitory concentration
  • Pathogenicity assay
  • Phylogenetic grouping
  • AFM of interactions between β-lactam antibiotics and E. coli

Research Details

Virulence is a quantitative measure of bacterial pathogenicity which is defined as the ability of bacteria to cause disease. To date, bacterial cells are classified as pathogens based solely on whether they have virulence factors that enable them to conquer different niches throughout the course of an infection. However, although the complete genome of most major bacterial pathogens have been sequenced, predicting bacterial pathogenicity is yet difficult. Such difficulty is largely influenced by the enormous diversity of virulence-related genes and by the fascinating ability of pathogens to express various virulence factors in response to different environmental stimuli. These difficulties point towards the need to design new ways independent from nucleic-acid amplification assays to diagnose pathogens.

Our lab is interested in distinguishing pathogenic from non-pathogenic bacteria using a physiochemical approach. The central hypothesis of this research is that a combination of nanoscale and macroscale physiochemical properties, including bacterial surface elasticity, wettability, charge, biopolymer composition, adhesion and biofilm formation will provide a profile for pathogens. Our research is expected to point to a new creative and original multiscale approach to profile pathogenic bacteria and to further distinguish them from non-pathogenic ones.

Funding Acknowledgements

NSF - National Science Foundation
3M
NIH National Institute of Allergy and Infectious Diseases