Poster Presentation BACPATH 2019

Characterization of Escherichia coli Adhesins (#207)

Tugce Onur 1 2 , Minh Duy Phan 1 2 , Kelvin Goh 1 2 , Jessica Poole 3 , Christopher Day 3 , Michael P. Jennings 3 , Mark Schembri 1 2
  1. School of Chemistry and Molecular Biosciences, The university of Queensland, Brisbane, Queensland, Australia
  2. Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Queensland, Australia
  3. Institute for Glycomics, Griffith University Gold Coast Campus, Gold Coast, Queensland, Australia

Uropathogenic Escherichia coli (UPEC) are the main causative agent of urinary tract infections (UTI), which are one of the most common infections in humans. Roughly 175 million cases of UTI are estimated to occur annually across the globe, accounting for more than 1 million hospitalizations and approximately $3.5 billion in medical expenditure each year in the USA alone. UPEC possess an array of virulence factors that mediate colonization of the urinary tract and enhance disease progression, including fimbriae.  In this study, our aim was to characterize one type of UPEC fimbriae referred to as Yad fimbriae. Yad fimbriae contribute to bladder colonization, but the mechanism by which this occurs remains to be elucidated. To characterize Yad fimbriae, we first performed an in silico analysis on a collection of 597 completely sequenced E. coli genomes to assess the prevalence and sequence conservation of genes in the yad operon. We found that the yad genes were present in 74% of these strains and clustered into four major clades. In silico analysis was performed for individual fimbrial elements including the major pilin, usher and tip adhesin. We found that the tip adhesin exhibits greater sequence variation than the major pilin and usher proteins. Hence, we focused on the characterization of tip located adhesin protein (YadC) of Yad fimbriae. To study the adhesive characteristics of YadC, the region encoding the lectin binding domain was cloned from strains representing each major Yad clade and expressed in an isogenic recombinant E. colibackground. The recombinant YadC proteins were purified by Ni-affinity chromatography under native conditions their receptor binding profile was assessed using a glycan array. Evaluation of this data is ongoing.