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Experimental pyelonephritis in mice following ascending infection with C. coli. Acute phase
Abstract:
The initial interaction between uroepithelial cells and Escherichia coli which has adhesive or invasive activity for cultured cells was studied ultrastructurally at the in situ of infection in the model of ascending pyelonephritis in mice. The densely piliated adhesive strain E77156 isolated from the urine of a patient with urinary tract infection adhered to the pelvic and renal tubular epithelial cells and colonized on their cell surfaces and thereafter in the cytoplasm. The non-piliated invasive strain 633-65 isolated from a patient with dysentery-like syndrome did not colonize on the uroepithelial cell surfaces but easily penetrated into the cytoplasm of these cells. Thereafter multiplication was observed in their cytoplasm. Neither strain scarcely penetrated into the interstitium via the basement membrane of the renal tubules.
Insights
This study reveals how different Escherichia coli strains interact with mouse kidney cells. Adhesive E. coli colonize cell surfaces and cytoplasm, while invasive strains penetrate cells to multiply, aiding understanding of urinary tract infections.
Area of Science:
- Urology
- Microbiology
- Cell Biology
Background:
- Urinary tract infections (UTIs) are common, often caused by Escherichia coli.
- Understanding bacterial interaction with uroepithelial cells is crucial for UTI pathogenesis.
- Ascending pyelonephritis models in mice provide insights into kidney infection dynamics.
Purpose of the Study:
- To ultrastructurally investigate the initial interaction between uroepithelial cells and distinct Escherichia coli strains.
- To differentiate the invasion mechanisms of adhesive versus invasive E. coli in a mouse model.
- To elucidate bacterial colonization and intracellular behavior within renal cells.
Main Methods:
- Utilized an in situ model of ascending pyelonephritis in mice.
- Employed ultrastructural analysis to observe host-pathogen interactions.
- Examined two distinct E. coli strains: a piliated adhesive strain (E77156) and a non-piliated invasive strain (633-65).
Main Results:
- The adhesive E. coli strain (E77156) adhered to and colonized uroepithelial cells, both on surfaces and within the cytoplasm.
- The invasive E. coli strain (633-65) bypassed surface colonization to directly penetrate uroepithelial cell cytoplasm for multiplication.
- Neither strain significantly penetrated the basement membrane into the renal interstitium.
Conclusions:
- Adhesive and invasive E. coli exhibit distinct initial interaction mechanisms with uroepithelial cells.
- Intracellular colonization and multiplication are key features of invasive E. coli in the renal tubules.
- The basement membrane acts as a barrier, limiting interstitial invasion by these E. coli strains in this model.