title: Analysis of the genetic determinants coding for the S-fimbrial adhesin (sfa) in different Escherichia coli strains causing meningitis or urinary tract infections.
abstract: Recently we have described the molecular cloning of the genetic determinant coding for the S-fimbrial adhesin (Sfa), a sialic acid-recognizing pilus frequently found among extraintestinal Escherichia coli isolates. Fimbriae from the resulting Sfa+ E. coli K-12 clone were isolated, and an Sfa-specific antiserum was prepared. Western blots indicate that S fimbriae isolated from different uropathogenic and meningitis-associated E. coli strains, including O83:K1 isolates, were serologically related. The Sfa-specific antibodies did not cross-react with P fimbriae, but did cross-react with F1C fimbriae. Furthermore the sfa+ recombinant DNAs and some cloned sfa-flanking regions were used as probes in Southern experiments. Chromosomal DNAs isolated from O18:K1 and O83:K1 meningitis strains with and without S fimbriae and from uropathogenic O6:K+ strains were hybridized against these sfa-specific probes. Only one copy of the sfa determinant was identified on the chromosome of these strains. No sfa-specific sequences were observed on the chromosome of E. coli K-12 strains and an O7:K1 isolate. With the exception of small alterations in the sfa-coding region the genetic determinants for S fimbriae were identical in uropathogenic O6:K+ and meningitis O18:K1 and O83:K1 strains. The sfa determinant was also detected on the chromosome of K1 isolates with an Sfa-negative phenotype, and specific cross-hybridization signals were visible after blotting against F1C-specific DNA. In addition homology among the different strains was observed in the sfa-flanking regions.
mesh_terms: D018830:Adhesins, Escherichia coli; D000942:Antigens, Bacterial / Q000235:genetics; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000472:pathogenicity; D010861:Fimbriae, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D008581:Meningitis / Q000382:microbiology*; D008970:Molecular Weight; D012689:Sequence Homology, Nucleic Acid; D012794:Sialic Acids; D013045:Species Specificity; D014552:Urinary Tract Infections / Q000382:microbiology*
chemical_list: D018830:Adhesins, Escherichia coli; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012794:Sialic Acids