title: Presence of cfaD-homologous sequences and expression of coli surface antigen 4 on enterotoxigenic Escherichia coli; relevance for diagnostic procedures.
abstract: We examined the ability of a colonization factor antigen I (CFA/I) polynucleotide probe to identify coli-surface antigen 4 producing (CS4+) strains of enterotoxigenic Escherichia coli (ETEC). At low stringency (LS) the probe hybridized to colony lysates of strains previously shown to produce CS4 or CFA/I fimbriae. Only DNA from CFA/I+ strains maintained a stable probe-target hybrid under high stringency (HS) conditions. On examination of several clones from three previous CS4 producers, identified as positive in LS and negative in HS colony hybridization, spontaneous loss of nucleotide sequences homologous to a gene encoding a positive CFA/I regulator, CfaD, was found to be associated with lacking expression of CS4. Our findings indicate that, on stored or subcultured isolates of ETEC, identification of CS4 strains may benefit from applying gene probe technology.
authors.affiliation: Centre for International Health, University of Bergen, Haukeland Hospital, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Sommerfelt
authors.forename: H M
authors.initials: HM
authors.lastname: Grewal
authors.forename: W
authors.initials: W
authors.lastname: Gaastra
authors.forename: M K
authors.initials: MK
authors.lastname: Bhan
authors.forename: A M
authors.initials: AM
authors.lastname: Svennerholm
authors.forename: K H
authors.initials: KH
authors.lastname: Kalland
authors.forename: V
authors.initials: V
authors.lastname: Asphaug
authors.forename: R
authors.initials: R
authors.lastname: Aasland
authors.forename: B
authors.initials: B
authors.lastname: Bjorvatn
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis / Q000235:genetics*; D000954:Antigens, Surface / Q000032:analysis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D015139:Blotting, Southern; D015342:DNA Probes; D004268:DNA-Binding Proteins; D004768:Enterotoxins / Q000096:biosynthesis; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D015870:Gene Expression; D005809:Genes, Regulator; D010641:Phenotype; D010957:Plasmids / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; C069375:CfaD protein, E coli; D015342:DNA Probes; D004268:DNA-Binding Proteins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C022924:colonization factor antigens; D036781:Fimbriae Proteins