Urinary tract infections can be severe, sometimes fatal, diseases whose etiological pathogens are predominantly uropathogenic strains of E. coli (UPEC). To investigate the UPEC pathogenesis, several models have already been established with minor or major disadvantages. The aim was to develop a simple, fast, and inexpensive biomimetic in vitro model based on normal porcine urothelial (NPU) cells that are genetically and physiologically similar to human bladder urothelium and to perform basic studies of E. coli pathogenicity. Initially, the model was tested using a set of control E. coli strains and, subsequently, with human E. coli strains isolated either from patients with urinary infections or from the feces of healthy individuals. A drop in viability of NPU cells was used as a measure of the pathogenicity of the individual strain tested. To visualize the subcellular events, transmission and scanning electron microscopy was performed. The strains were tested for the presence of different virulence-associated genes, phylogroup, type of core lipid, O-serotype, and type of lipopolysaccharide and a statistical analysis of possible correlations between strains’ characteristics and the effect on the model was performed. Results showed that our model has the discriminatory power to distinguish pathogenic from non-pathogenic E. coli strains, and to identify new, potentially pathogenic strains.

Iron uptake and bacteriocin genes among Escherichia coli strains from skin and soft-tissue infections APMIS 125: 264-267

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Escherichia coli is known to be an important uropathogenic agent. Several models were developed for investigating the uropathogensis of E. coli, including the recent biomimetic porcine urothelial in vitro model. The aim of this study was to assess the cytokine response of the cells of the biomimetic porcine urothelial model to different E. coli strains. The production of nine different cytokines in response to E. coli infection was evaluated using the commercial pre-configured immunoassay multiplex Cytokine & Chemokine 9-Plex Porcine ProcartaPlex™ Panel 1 kit. Our results showed that cells of the biomimetic porcine urothelial model reacted to the presence of all the employed different E. coli strains, albeit with some differences in levels and types of cytokines produced. Increased production of IL-10, IL-8, TNF-α, IL-1β, IL-4 and IL-12p40 was observed. Statistical analysis (Fisher’s exact test) revealed a correlation between the high fold change in the immune response and the presence of the cnf1 gene that encodes the cytotoxic necrotizing factor. Our results shed light on the cytokine response of normal urothelial cells to different E. coli strains and have the potential to fuel the search for understanding the mechanisms behind the different cytokine responses to different E. coli strains.

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