Identification of Coli Surface Antigen 23, a Novel Adhesin of Enterotoxigenic Escherichia coli

TitleIdentification of Coli Surface Antigen 23, a Novel Adhesin of Enterotoxigenic Escherichia coli
Publication TypeJournal Articles
Year of Publication2012
AuthorsDel Canto F, Botkin DJ, Valenzuela P, Popov V, Ruiz-Perez F, Nataro JP, Levine MM, Stine OC, Pop M, Torres AG, others
JournalInfection and immunity
Volume80
Issue8
Pagination2791 - 2801
Date Published2012
Abstract

Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea, mainly in developing countries. Although there are 25 different ETEC adhesins described in strains affecting humans, between 15% and 50% of the clinical isolates from different geographical regions are negative for these adhesins, suggesting that additional unidentified adhesion determinants might be present. Here, we report the discovery of Coli Surface Antigen 23 (CS23), a novel adhesin expressed by an ETEC serogroup O4 strain (ETEC 1766a), which was negative for the previously known ETEC adhesins, albeit it has the ability to adhere to Caco-2 cells. CS23 is encoded by an 8.8-kb locus which contains 9 open reading frames (ORFs), 7 of them sharing significant identity with genes required for assembly of K88-related fimbriae. This gene locus, named aal (adhesion-associated locus), is required for the adhesion ability of ETEC 1766a and was able to confer this adhesive phenotype to a nonadherent E. coli HB101 strain. The CS23 major structural subunit, AalE, shares limited identity with known pilin proteins, and it is more closely related to the CS13 pilin protein CshE, carried by human ETEC strains. Our data indicate that CS23 is a new member of the diverse adhesin repertoire used by ETEC strains.