Distribution of aggA and aafA gene sequences among Escherichia coli isolates with genotypic or phenotypic characteristics, or both, of enteroaggregative E. coli

J Med Microbiol. 1999 Jun;48(6):597-599. doi: 10.1099/00222615-48-6-597.


Two types of fimbriae, designated aggregative adherence fimbria I and II (AAF/I and AAF/II) have been described in enteroaggregative Escherichia coli (EAEC) strains. These fimbriae mediate the aggregative pattern of adherence (AA) to epithelial cells. The genes encoding the structural subunit of each fimbria have been designated aggA and aafA, respectively. The prevalence of these genes was investigated in 155 faecal EAEC isolates that displayed AA to HeLa cells and were isolated from children in São Paulo, Brazil. Hybridisation assays with aggA and aafA sequences showed that 9.7% of these isolates carried aggA, 3.9% aafA, and none hybridised with both sequences. Of the 78 isolates displaying AA that reacted with the previously described EAEC probe (CVD432), 19.2% and 7.7% hybridised with the aggA and aafA probes, respectively. None of the 77 isolates displaying AA but lacking the EAEC probe sequence hybridised with either probe. These results clearly indicate that additional factors are involved in the AA phenotype in these EAEC strains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Adhesion / genetics*
  • Brazil
  • Case-Control Studies
  • Child, Preschool
  • DNA Probes / chemistry
  • DNA, Bacterial / chemistry
  • Diarrhea / microbiology
  • Escherichia coli / classification
  • Escherichia coli / genetics*
  • Escherichia coli / pathogenicity
  • Escherichia coli Infections / microbiology
  • Feces / microbiology
  • Fimbriae, Bacterial / genetics*
  • Genotype
  • HeLa Cells
  • Humans
  • Infant
  • Intestines / microbiology
  • Nucleic Acid Hybridization
  • Phenotype


  • DNA Probes
  • DNA, Bacterial