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Properties of Escherichia coli isolates from urinary tract infections in boys
B Westerlund1, A Siitonen, J Elo
1Department of General Microbiology, University of Helsinki, Finland.
Insights
Escherichia coli strains causing urinary tract infections (UTI) in young boys share virulence factors with those in girls. However, lower UTI strains in boys showed no difference from pyelonephritis strains regarding P fimbriae, hemolysin, and type 1C fimbriae.
Area of Science:
- Pediatric Infectious Diseases
- Microbiology
- Urology
Background:
- Urinary tract infections (UTI) are common in young children.
- Escherichia coli is the primary pathogen causing UTI.
- Virulence factors of E. coli may differ in association with UTI severity and sex.
Purpose of the Study:
- To compare virulence factors of E. coli isolates from boys and girls with UTI.
- To investigate the association of specific virulence factors with pyelonephritis (PN) versus lower UTI in both sexes.
Main Methods:
- Comparative analysis of 55 E. coli urine isolates from boys and girls (<3 years) with UTI.
- Assessment of P fimbriae, hemolysin, type 1C fimbriae, and aerobactin production.
- Serotyping (O4, O6) and clonal analysis.
Main Results:
- P fimbriae, hemolysin, and type 1C fimbriae were frequent in boys' UTI isolates, similar to girls' PN-associated strains.
- Boys' lower UTI strains did not differ from PN-associated strains in these three factors.
- Aerobactin production was linked to PN in both sexes.
- Serotypes O4 and O6 were overrepresented in boys' UTI and girls' PN strains, linked to three clones, including a new one in boys.
Conclusions:
- E. coli virulence factor profiles in young boys with UTI are similar to those in girls, even for lower UTI.
- Aerobactin production is a significant marker for pyelonephritis in both sexes.
- Specific E. coli clones, including novel ones, contribute to UTI prevalence and severity in young children.
Abstract:
Fifty-five isolates of Escherichia coli from urine of boys younger than three years of age with urinary tract infection (UTI) were compared with strains from girls of the same age range who had UTI. The frequency of P fimbriae, hemolysin, and type 1C fimbriae, previously described as associated with pyelonephritis (PN) in girls, was also high (76%, 60%, and 31%, respectively) in UTI-associated strains from boys. However, in contrast to isolates from girls, strains from lower UTI in boys did not differ from PN-associated strains regarding these three characteristics. In contrast, aerobactin production was significantly associated with PN compared with lower UTI in both sexes. Serotypes O4 and O6 were overrepresented among all UTI-associated strains from boys and PN-associated strains from girls. This overrepresentation was largely accounted for by three clones, one of which was a new clone identified among the UTI-associated strains from boys.