February 21, 2023

Towards the Development of Cryo-electron Tomography as Diagnostic Tool for Recurrent Urinary Tract Infections

5th Call, iDoc

Short Summary

Urinary tract infections (UTIs) are among the most common bacterial infections and about 25% of patients experience a recurrent UTI. The vast majority of UTIs are caused by uropathogenic E. coli, which can proliferate in the bladder lumen but are also capable to form intracellular bacterial communities (IBCs) within the cytoplasm of infected urothelial cells. These IBCs exhibit biofilm-like properties, protecting the pathogen from host defenses and antibiotics. IBCs are a potential cause of recurrent UTIs, but a fundamental understanding of IBC architecture is missing. This iDoc projects aims to develop cryo-electron tomography as diagnostic tool for direct analysis of IBCs in exfoliated urothelial cells from patients with acute UTIs. The results will identify new virulence factors which will guide us to new treatment strategies against recurrent UTIs.

Goals

This iDoc project aims to develop cryo-electron tomography (cryoET) as diagnostic tool for direct analysis of IBCs in exfoliated uroepithelial cells from patients with acute UTIs. CryoET enables macromolecular insights into infected patient cells, allowing the dissection of IBC ultrastructure at unprecedented resolution. We will establish workflows for processing exfoliated uroepithelial cells from patient urine for subsequent cryoET imaging. This will help to discover new virulence factors involved in IBC formation by an integrative analysis of cryoET data with complementary techniques. The established workflow will be subsequently used to compare IBCs in individual patients.

Significance

The alarming increase of multidrug resistant uropathogens reinforces the urgent need for a fundamental and detailed understanding of the molecular and cellular processes causing recurrent UTIs in patients. The lack of knowledge prevents the development of more targeted and personalized treatments. Our approach will provide pivotal insights in IBC architecture and it will further allow to discover novel virulence factors guiding us to new and personalized treatment strategies against UTIs.

Background

Urinary tract infections (UTIs) are among the most common bacterial infections in humans. Besides being generally considered to be extracellular infections, they are often incompletely resolved. About 25% of patients experience a recurrent UTI and the resulting repetitive administration of antibiotics contributed to higher antibiotic resistance rates in uropathogens. Up to 90% of UTIs are caused by uropathogenic E. coli (UPEC), which can proliferate in the bladder lumen but are also capable of invading uroepithelial cells where they form intracellular bacterial communities (IBCs). These IBCs exhibit biofilm-like properties, protecting the pathogen from host defenses and antibiotics, and IBCs are a potential cause for the development of recurrent UTIs. A fundamental understanding of the underlying cellular processes during IBC formation is still missing, hence preventing the development of targeted and personalized treatment strategies.