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Bacterial virulence and inflammatory response in infants with febrile urinary tract infection or screening
S Mårild1, B Wettergren, M Hellström
1Department of Pediatrics, University of Göteborg, Sweden.
Insights
Attaching Escherichia coli strains are more common in infants with febrile urinary tract infections (UTIs). These bacterial strains also cause more inflammation, suggesting adherence plays a key role in UTI pathogenesis.
Area of Science:
- Pediatrics
- Microbiology
- Immunology
Background:
- Urinary tract infections (UTIs) are common in infants.
- Understanding the virulence factors of uropathogens is crucial for managing pediatric UTIs.
- The role of bacterial adherence in UTI pathogenesis requires further elucidation.
Purpose of the Study:
- To compare the inflammatory response and bacterial characteristics in infants with febrile UTIs versus asymptomatic bacteriuria.
- To investigate the association between Escherichia coli adherence and inflammatory markers in infants.
Main Methods:
- Prospective analysis of two infant populations: febrile UTI and asymptomatic bacteriuria.
- Bacteriuria confirmed by bladder puncture; inflammatory response assessed via fever, CRP, ESR, and urinary leukocytes.
- Bacterial characterization included O:K:H serotype, hemolysin production, serum resistance, and uroepithelial cell attachment.
Main Results:
- Significantly higher frequency of inflammatory signs and attaching E. coli in febrile UTI infants compared to the screening group.
- Within both groups, infants infected with attaching E. coli strains exhibited more pronounced inflammatory signs.
- A strong correlation was observed between bacterial adherence and increased inflammation.
Conclusions:
- Bacterial adherence, specifically by attaching E. coli, is associated with increased inflammation in infant UTIs.
- Adherence may facilitate the presentation of bacterial components that trigger inflammatory responses in the urinary tract tissues.
- These findings highlight the importance of bacterial virulence factors in determining UTI severity in infants.
Abstract:
Two populations were analyzed prospectively after a first episode of urinary tract infection. Asymptomatic infants were screened at 2 weeks and at 3 and 10 months of age, and bacteriuria was confirmed by bladder puncture. Infants with febrile urinary tract infection were enrolled during the same study period. The inflammatory response was characterized by the presence of fever, serum C-reactive protein, microsedimentation rate, urinary leukocyte excretion, and width of the ureters. The bacteria were defined for O:K:H serotype, hemolysin production, resistance to the bactericidal effect of serum, attachment to uroepithelial cells, and specificity for the globoseries of glycolipid receptors. In agreement with previous studies, the frequency of increased inflammatory signs and of attaching Escherichia coli was significantly higher in infants with febrile urinary tract infection than in the screening group. Within both patient groups, however, children infected with attaching E. coli strains had significantly more inflammatory signs. The results suggest that adherence facilitates the presentation of bacterial components capable of causing inflammation in the tissues in the urinary tract.