Microbial colonization of human ileal conduits.

Area of Science:

• Urology
• Microbiology
• Surgical Pathology

Background:

• Ileal conduits are open, unvalved urinary diversion systems susceptible to microbial colonization.
• Ascending growth of pathogenic organisms in ileal conduits can cause life-threatening pyelonephritis.
• Understanding the microbial ecology is crucial for managing complications in patients with ileal conduits.

Purpose of the Study:

• To identify microorganisms colonizing human ileal conduits over time.
• To investigate the ecological sequence of microbial colonization in ileal conduits.
• To examine the interaction of microorganisms with ileal tissue surfaces.

Main Methods:

• Morphological and microbiological techniques were employed.
• 17 patients with ileal conduits were studied from 5 days to 16 years post-surgery.
• Transmission and scanning electron microscopy were used to examine ileal microvillus surfaces.

Main Results:

• Ileal microvillus surfaces remained uncolonized by bacteria, even after years of conduit service.
• Initially (10 days), yeasts dominated mucus and urine during antibiotic therapy.
• A mixed flora of yeasts and gram-positive cocci developed; gram-negative organisms emerged as antibiotics were withdrawn, correlating with pyelonephritis.

Conclusions:

• Ileal tissue surfaces resist bacterial colonization despite heavy external microbial load.
• The microbial ecology of ileal conduits shifts over time, influenced by antibiotic use.
• Gram-negative bacteria emerging in the conduit flora are associated with pyelonephritis.