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An electron microscopic study of pathogenesis of urinary tract infection caused by Pseudomonas aeruginosa P 9 in mice
Abstract:
Scanning and transmission electron microscopic examination of the kidney and bladder of mice infected transurethrally with Pseudomonas aeruginosa P 9 revealed that the pyelonephritis is established through two routes, after the organisms reach the pelvis of the kidney via the bladder and ureter. In one route, which appeared to be predominant, the inoculated bacteria invaded the renal parenchyma through exfoliation of the calyceal epithelial cells with subsequent destruction of the basement membrane. Alternatively, the inoculated bacteria retrograded in the collecting tubules and urineferous tubules and propagated in the lumina followed by invasion of the renal parenchyma. In the bladder, the inoculated bacteria increased in number then disappeared within 48 h after exhibiting morphological aberrations such as elongation, bulge and spheroplast formation.
Insights
Pseudomonas aeruginosa causes pyelonephritis in mice through two main pathways. Bacteria invade the kidney parenchyma by damaging calyceal cells or by retrograde spread through tubules.
Area of Science:
- Microbiology
- Pathology
- Nephrology
Background:
- Urinary tract infections (UTIs) are common, with Pseudomonas aeruginosa being a significant pathogen.
- Pyelonephritis, an upper UTI affecting the kidneys, can lead to severe complications.
Purpose of the Study:
- To elucidate the mechanisms by which Pseudomonas aeruginosa establishes pyelonephritis in a murine model.
- To investigate the bacterial behavior and morphological changes in the bladder during infection.
Main Methods:
- Transurethral inoculation of mice with Pseudomonas aeruginosa P 9.
- Scanning and transmission electron microscopy of infected kidney and bladder tissues.
Main Results:
- Two distinct routes for pyelonephritis establishment were identified: direct invasion via calyceal epithelial cell exfoliation and retrograde spread through tubules.
- Bacteria demonstrated morphological aberrations, including elongation and spheroplast formation, in the bladder before clearance within 48 hours.
Conclusions:
- Pseudomonas aeruginosa employs multiple strategies to invade the renal parenchyma.
- The bladder environment induces significant bacterial morphological changes, potentially related to immune evasion or clearance mechanisms.