Diffuse adherence, ST-I enterotoxin and CFA/IV colonization factor are encoded by the same plasmid in the Escherichia coli O29: H21 strai

Escherichia coli O29:H21 is a human enterotoxigenic serotype that produces heat-stable (ST-I) enterotoxin, adheres diffusely to HeLa cells, and presents colonization factor antigen IV (CFA/IV) composed of CS5CS6 surface antigens. In one strain studied the genes for diffuse adherence and CFA/IV (CS5CS6) production were found to be present in the same plasmid encoding ST-I. The virulence plasmid (Ent) presented two unrelated basic replicons homologous to repFIC and repW. Gene(s) encoding diffuse adherence did not share homology with the probe for F1845 fimbrial adhesin which is responsible for this phenotype in other E. coli strains. Ent plasmid containing genes for diffuse adherence have not been described previously.

Presence of colonization factor antigen IV (CS5CS6) in O29:H21 enterotoxigenic Escherichia coli isolated from children with diarrhea in Brazil

1. Enterotoxigenic Escherichia coli (ETEC) strains belonging to serotype O29:H21 were analyzed for the presence of colonization factor antigens (CFA). 2. CFA/IV was detected in all twelve strains studied, and immunological analysis demonstrated that it was composed of coli surface antigens 5 (CS5) and 6 (CS6) presenting molecular weights of approximately 21 kDa and approximately 16 kDa, respectively. 3. CS6 antigenic homology was observed between O29:H21 and reference strains E11881C and E17018A. 4. CS6 of the O29:H21 strains was composed of two peptide bands, similar to the reference strain E17018A