Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2018

Characterization of Escherichia coli Adhesins (#405)

Tugce Onur 1 2 , Alvin Lo 1 2 , Kelvin Goh 1 2 , Begona Heras 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. Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia

Uropathogenic Escherichia coli (UPEC) are the main causative agent of urinary tract infections, which are one of the most common infections of humans. Roughly 175 million cases of UTI are estimated to occur annually across the globe, accounting for >1 million hospitalisations and ~$3.5 billion in medical expenditure each year in the USA alone. UPEC strains possess an array of factors which allow them to colonise a host and cause disease, including autotransporter (AT) proteins and fimbriae.  In this study, our aim was to characterise two E. coli adhesins: the YfaL AT protein and Yad fimbriae.To characterise YfaL, we first performed an in silico analysis on a collection of 185 complete E. coli genomes to assess the prevalence and sequence conservation of the yfaL gene. We found that the yfaL gene was present in 86% of the strains and based on amino acid sequence relatedness clustered in line with E. coli phylogrouping. To study the functional characteristics of the YfaL, representative yfaL variants from each major clade were cloned and expressed in an isogenic recombinant E. coli background. Phenotypic analyses revealed that some variants were able to mediate biofilm formation. To characterize E. coli Yad fimbriae, in silico analysis was performed on the E. coli complete genome collection. The yad genes were highly prevalent (74% of strains) and clustered into four major clades based on amino acid sequence. 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. For functional characterization, representative yad fimbriae genes have been cloned and expressed in an isogenic recombinant E. coli background. Characterisation of the YfaL protein and Yad fimbriae is ongoing.