부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.micpath.2007.06.009 Byline: Matilda Nicklasson (a), Asa Sjoling (a), Michael Lebens (a), Joshua Tobias (a), Anders Janzon (a), Lars Brive (b), Ann-Mari Svennerholm (a) Keywords: Enterotoxigenic Escherichia coli; Chaperone; Bacterial SNP; Adhesion; Virulence factor; Coli surface antigen 6 (CS6) Abstract: Enterotoxigenic Escherichia coli (ETEC) cause diarrhoea by adhesion to human enterocytes by one or more colonization factors (CFs) and secretion of heat-labile (LT) and/or heat-stable (ST) enterotoxins. Expression of coli surface antigen 6 (CS6) on the bacterial surface, usually associated with ETEC strains that produce ST alone or in combination with LT, is rarely found in strains expressing only LT. However, a number of LT-only strains which are genotypically positive but phenotypically negative for CS6 have been identified. In this study, eight such strains from India and Guinea-Bissau belonging to different clones were analysed. The CS6 operon cssABCD was transcribed but protein analyses suggested that the structural subunits CssA and CssB of CS6 were absent in the periplasm. Most strains contained truncating mutations within the periplasmic chaperone-encoding gene cssC and protein modelling indicated that this severely affected the substrate-binding capacity of the chaperone. A single-nucleotide polymorphism (SNP) (A[right arrow]T) in the 5'-untranslated region of cssC distinguished the eight strains from ETEC strains that do express CS6 on the surface and may be a potential marker for ETEC strains containing phenotypically silent cssABCD. The study emphasizes the importance of using both genotypic and phenotypic methods in epidemiological studies of ETEC, e.g. for vaccine development. Author Affiliation: (a) Department of Microbiology and Immunology, Institute of Biomedicine, Goteborg University, P.O. Box 435, 405 30 Goteborg, Sweden (b) Department of Cellular and Molecular Biology, Goteborg University, P.O. Box 462, 405 30 Goteborg, Sweden Article History: Received 30 March 2007; Accepted 11 June 2007