title: Clonal clustering and colonization factors among thermolabile and porcine thermostable enterotoxin-producing Escherichia coli.
abstract: A considerable proportion of enterotoxigenic Escherichia coli (ETEC) do not possess identifiable colonization factors (CFs). Genetic fingerprint analyses based on repetitive sequence-based polymerase chain reaction (rep-PCR) showed that 9 of 10 such CF-negative isolates which produced the thermolabile and the porcine thermostabile enterotoxin could be divided into three clusters. Following transformation with a plasmid harbouring the gene encoding CfaR, a positive regulator for several ETEC adhesins, three of the six strains in the first cluster expressed coli surface antigen 20 (CS20). No CFs were identified on the two transformed strains in the second cluster while the transformants of the two strains in the last cluster expressed CS12, the N-terminal amino acid sequence of which was deciphered. The study illustrates the potential of using genetic fingerprinting to group ETEC into clusters of strains with genes encoding different CFs and confirms the ability of CfaR to induce the expression of several different CFs.
authors.affiliation: Centre for International Health, University of Bergen, Norway.
authors.forename: Håvard
authors.initials: H
authors.lastname: Valvatne
authors.forename: Hans
authors.initials: H
authors.lastname: Steinsland
authors.forename: Halvor
authors.initials: H
authors.lastname: Sommerfelt
mesh_terms: D000595:Amino Acid Sequence; D001427:Bacterial Toxins / Q000096:biosynthesis*; D016172:DNA Fingerprinting; D004768:Enterotoxins / Q000096:biosynthesis*; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000276:immunology*; D029968:Escherichia coli Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D036781:Fimbriae Proteins / Q000032:analysis* / Q000235:genetics; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D010957:Plasmids; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C022924:colonization factor antigens; C034151:heat stable toxin (E coli); D036781:Fimbriae Proteins