Bacterial adherence as a virulence factor in urinary tract infection

Area of Science:

• Pediatric Nephrology
• Infectious Diseases
• Microbiology

Background:

• Escherichia coli (E. coli) is responsible for over 90% of childhood urinary tract infections (UTI).
• Uropathogenic E. coli adherence to urinary tract epithelial cells is mediated by bacterial adhesins interacting with host glycolipid receptors, particularly the Galactose alpha 1-greater than 4Galactose beta (Gal alpha 1-greater than 4Gal beta) disaccharide.
• Certain E. coli strains possessing the Gal alpha 1-greater than 4Gal beta-binding specificity are associated with more severe UTI outcomes.

Purpose of the Study:

• To investigate the clinical significance of Gal alpha 1-greater than 4Gal beta-binding E. coli in childhood UTI.
• To determine the association between Gal alpha 1-greater than 4Gal beta-positive E. coli infection and the risk of renal scarring.
• To explore the role of inflammatory markers and cytokines in UTI pathogenesis.

Main Methods:

• Comparison of clinical parameters (body temperature, C-reactive protein, erythrocyte sedimentation rate, pyuria, renal concentrating capacity) between children with Gal alpha 1-greater than 4Gal beta-positive and negative E. coli UTI.
• Assessment of renal scarring frequency in relation to E. coli binding specificity.
• Detection of bacterial binding using a commercially available test reagent.
• Investigation of interleukin-6 (IL-6) production in response to UTI.

Main Results:

• Children with Gal alpha 1-greater than 4Gal beta-binding E. coli UTI exhibited significantly higher body temperature, CRP, ESR, and pyuria, and reduced renal concentrating capacity compared to those with non-binding strains.
• The frequency of renal scarring was markedly higher (40%) in boys infected with Gal alpha 1-greater than 4Gal beta-negative E. coli compared to those with Gal alpha 1-greater than 4Gal beta-positive E. coli (5%).
• A commercially available reagent for detecting Gal alpha 1-greater than 4Gal beta binding proved effective in predicting renal scarring risk.

Conclusions:

• Gal alpha 1-greater than 4Gal beta-binding E. coli strains are more potent inducers of inflammation and are associated with a lower risk of renal scarring in boys with childhood UTI.
• The detection of bacterial Gal alpha 1-greater than 4Gal beta binding serves as a valuable predictor for renal scarring risk.
• Interleukin-6 (IL-6) and other pro-inflammatory cytokines likely contribute to the systemic inflammatory response observed in symptomatic UTI.