The ultrastructure of acute pyelonephritis in the monkey

Area of Science:

• Urology
• Microbiology
• Pathology

Background:

• P-fimbriated Escherichia coli (E. coli) possess fimbriae that bind to specific receptors on urothelial cells.
• This interaction is a key factor in the development of pyelonephritis, a kidney infection.

Purpose of the Study:

• To investigate the temporal dynamics of P-fimbriated E. coli adherence and tissue response in the ureter and kidney.
• To elucidate the early stages of pyelonephritis development at the cellular and tissue level.

Main Methods:

• Scanning and transmission electron microscopy were employed to visualize bacterial attachment and host cell interactions.
• Inoculation of P-fimbriated E. coli in a model system to induce pyelonephritis.

Main Results:

• Bacteria adhered to ureteral epithelium within 12 hours, forming a biofilm by 48 hours without invasion.
• In the kidney, bacterial adherence to tubules occurred by 6 hours, with normal epithelium for 24 hours.
• Inflammation initiated at 48 hours, leading to phagocyte and tubular damage, followed by interstitial invasion.

Conclusions:

• P-fimbriated E. coli initially colonize urothelial surfaces without immediate invasion.
• The host inflammatory response contributes to tissue damage, facilitating bacterial spread into the interstitium.
• Understanding these early events is crucial for developing targeted therapies against pyelonephritis.