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Virulence factors in Escherichia coli from urinary tract infections in patients with spinal injuries
1School of Pure and Applied Biology, University of Wales College of Cardiff, UK.
Abstract:
A collection of 70 strains of Escherichia coli from urinary tract infections in spine-injured patients undergoing long-term bladder catheterization were tested for characteristics that have been associated with the ability to produce pyelonephritis. The incidence of the virulence factors were: mannose-resistant haemagglutinins (30%), P-fimbriae (17%), haemolysin (27%), K-antigens (28%) and aerobactin (by bioassay 33%, by gene probe 39%). Only 54% of the strains belonged to the O-serotypes usually associated with urinary tract infections. E. coli carrying the full complement of virulence factors were rare in the urinary tract of the spinal patients and were not associated with episodes of symptomatic pyelonephritis. It is clear that the neuropathic bladder and the presence of the catheter permits a wide variety of bacterial types to colonize the urinary tract and cause infection of the kidney. The identification of host markers rather than bacterial factors is suggested as a more fruitful approach to the early detection of cases likely to progress to pyelonephritis in this group of patients.
Insights
Infections in spine-injured patients with catheters are often caused by diverse Escherichia coli strains. Bacterial virulence factors are not reliable predictors of pyelonephritis in this population.
Area of Science:
- Microbiology
- Urology
- Infectious Diseases
Background:
- Spine-injured patients with long-term bladder catheters are susceptible to urinary tract infections (UTIs).
- Pyelonephritis, a severe kidney infection, is a significant complication of UTIs in this vulnerable group.
- Understanding the characteristics of Escherichia coli strains causing these infections is crucial.
Purpose of the Study:
- To investigate the prevalence of virulence factors in Escherichia coli strains isolated from spine-injured patients with UTIs.
- To determine the association between specific virulence factors and the development of pyelonephritis in this patient cohort.
- To explore alternative strategies for predicting pyelonephritis risk.
Main Methods:
- Analysis of 70 Escherichia coli strains from urine samples of spine-injured patients.
- Testing for virulence factors including mannose-resistant haemagglutinins, P-fimbriae, haemolysin, K-antigens, and aerobactin.
- Serotyping of E. coli strains to identify common UTI-associated O-serotypes.
- Correlation of bacterial characteristics with clinical outcomes, specifically symptomatic pyelonephritis.
Main Results:
- A wide range of virulence factors were observed, but strains with a full complement were rare.
- Mannose-resistant haemagglutinins (30%), P-fimbriae (17%), haemolysin (27%), K-antigens (28%), and aerobactin (33-39%) were present in varying frequencies.
- Only 54% of strains belonged to typical UTI-associated O-serotypes.
- The presence of virulence factors did not correlate with symptomatic pyelonephritis episodes.
Conclusions:
- Neuropathic bladder and catheterization facilitate colonization by diverse bacterial types, leading to kidney infections.
- Bacterial virulence factors are poor predictors of pyelonephritis in spine-injured patients.
- Focusing on host-related markers may offer a more effective approach for early pyelonephritis detection in this population.