Identification and characterization of CS20, a new putative colonization factor of enterotoxigenic Escherichia coli.
An enterotoxigenic Escherichia coli (ETEC) strain producing a previously undescribed putative colonization factor was isolated from a child with diarrhea in India. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of bacterial heat extracts revealed a polypeptide band of 20.8 kDa when the bacteria were grown at 37 degrees C which was absent after growth at 22 degrees C. A specific rabbit antiserum raised against the purified 20.8-kDa protein bound specifically to the fimbriae, as shown by immunoelectron microscopy, and inhibited bacterial adhesion to tissue-cultured Caco-2 cells. Transformation with a recombinant plasmid harboring the cfaD gene, which encodes a positive regulator for several ETEC fimbriae, induced hyperexpression of the 20.8-kDa fimbrial subunit and a substantial increase in the proportion of bacterial cells that were fimbriated. The N-terminal amino acid sequence of the polypeptide showed 65 and 60% identity to the PCFO20 and 987P fimbriae of human and porcine ETEC, respectively. We propose the term CS20 for this new putative colonization factor of human ETEC.
Valvatne
H
H
Centre for Internation Health, University of Bergen, Norway. Havard. Valvatne@bio.uib.no
Sommerfelt
H
H
Gaastra
W
W
Bhan
M K
MK
Grewal
H M
HM
D018829:Adhesins, Bacterial / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D004768:Enterotoxins / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D005798:Genes, Bacterial; D005809:Genes, Regulator; D006801:Humans; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010957:Plasmids / Q000235:genetics; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D013552:Swine; D014170:Transformation, Genetic
D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D004768:Enterotoxins