Chaperone-Usher Pili Loci of Colonization Factor-Negative Human Enterotoxigenic Escherichia coli

摘要: Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes diarrhea worldwide. Among 25 different ETEC adhesins, 22 are known as “colonization factors” (CFs), which 17 assembled by chaperone-usher (CU) mechanism. Currently, there no preventive therapy against ETEC, and CFs have been proposed components for vaccine development. However, studies diarrhea-causing strains worldwide indicate that between 15-50% these negative CFs, hindering selection widespread structures suggesting unknown adhesins remain to be identified. Here, we report result a comprehensive analysis 35 draft genomes do not carry adhesin genes; our goal was find new CU pili loci. The phylogenetic profiles serogroups were highly diverse, majority produced only heat-labile toxin. We identified ten loci belonging families β (1 locus), γ2 (7 loci), κ locus) π all contained required number open reading frames encode functional structures. Three variants previously-known clusters, three had only-partially described, four novel Intra-loci genetic variability would allow synthesis up 14 Clusters putative γ2-CU (23 strains), followed β-CU (12 yet fully characterized. Overall, findings significantly increase adhesion genes asscoated with human infections.