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Escherichia coli in infants' intestinal microflora: colonization rate, strain turnover, and virulence gene carriage

Forough Nowrouzian1, Bill Hesselmar, Robert Saalman

  • 1Department of Clinical Bacteriology, Sahlgrenska University Hospital, Göteborg, Sweden. forough.nowrouzian@microbio.gu.se

Pediatric Research
|April 18, 2003
PubMed

Insights

Escherichia coli colonization in infants is delayed and strain turnover is slow, suggesting reduced exposure. Virulence factors like P fimbriae aid E. coli persistence in the infant gut microbiome.

Area of Science:

  • Microbiology
  • Pediatrics
  • Human Microbiome

Background:

  • Escherichia coli colonization patterns in infants may be changing due to modern lifestyles.
  • Understanding early-life gut microbial colonization is crucial for infant health.

Purpose of the Study:

  • To characterize Escherichia coli (E. coli) colonization and strain dynamics in healthy Swedish infants.
  • To identify factors influencing E. coli persistence and virulence gene prevalence.

Main Methods:

  • Longitudinal study of 70 infants over the first year of life.
  • E. coli isolation from rectal swabs and fecal samples.
  • Strain typing via random amplified polymorphic DNA and virulence gene identification using multiplex PCR.

Main Results:

  • Late colonization by E. coli observed, with only 61% positive by 2 months.
  • Slow strain turnover rate (1.5 strains/infant over 6 months).
  • Genes for type 1 fimbriae, P fimbriae, and hemolysin were more common in persistent strains.

Conclusions:

  • Swedish infants show late E. coli colonization and low strain turnover, indicating limited exposure.
  • Virulence factors, particularly P fimbriae, facilitate E. coli persistence in the infant gut.
  • Presence of pets, specifically cats, correlated with a higher prevalence of P-fimbrial adhesin genes in E. coli strains.

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