Role of the <scp>YehD</scp> fimbriae in the virulence‐associated properties of enteroaggregative <scp> Escherichia coli </scp>

Made available in DSpace on 2022-04-29T08:32:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The interaction of enteroaggregative Escherichia coli (EAEC) strains with the colonic gut mucosa is characterized by the ability of the bacteria to form robust biofilms, to bind mucin, and induce a local inflammatory response. These events are mediated by a repertoire of five different aggregative adherence fimbriae variants (AAF/I-V) typically encoded on virulence plasmids. In this study, we report the production in EAEC strains of a new YehD fimbriae (YDF), which is encoded by the chromosomal gene cluster yehABCD, also present in most E. coli strains. Immuno-labelling of EAEC strain 042 with anti-AAF/II and anti-YDF antibodies demonstrated the presence of both AAF/II and YDF on the bacterial surface. We investigated the role of YDF in cell adherence, biofilm formation, colonization of spinach leaves, and induction of pro-inflammatory cytokines release. To this aim, we constructed yehD deletion mutants in different EAEC backgrounds (strains 17-2, 042, 55989, C1010, 278-1, J7) each harbouring one of the five AAFs. The effect of the YDF mutation was strain dependent and AAF independent as the lack of YDF had a different impact on the phenotypes manifested by the different EAECs tested. Expression of the yehABCD operon in a E. coli K12 ORN172 showed that YDF is important for biofilm formation but not for adherence to HeLa cells. Lastly, screening of pro-inflammatory cytokines in supernatants of Caco-2 cells infected with EAEC strains 042 and J7 and their isogenic ΔyehD mutants showed that these mutants were significantly defective in release of IL-8 and TNF-α. This study contributes to the understanding of the complex and diverse mechanisms of adherence of EAEC strains and identifies a new potential target for preventive measures of gastrointestinal illness caused by EAEC and other E. coli pathogroups. Department of Pediatrics University of Virginia School of Medicine Unidad de Investigaci&#243;n M&#233;dica en Enfermedades Infecciosas y Parasitarias Centro M&#233;dico Nacional Siglo XXI Instituto Mexicano de Seguro Social Centro de Detecci&#243;n Biomolecular Benem&#233;rita Universidad Aut&#243;noma de Puebla University of Florida Emerging Pathogens Institute Departamento de Patologia Universidade Federal do Maranh&#227;o Departamento de Microbiologia e Imunologia Instituto de Biociencias da UNESP Facultad de Estomatolog&#237;a Benem&#233;rita Universidad Aut&#243;noma de Puebla Departamento de Biolog&#237;a Celular Centro de Investigaciones Avanzadas Instituto Polit&#233;cnico Nacional Centro de Investigaciones en Ciencias Microbiol&#243;gicas Benem&#233;rita Universidad Aut&#243;noma de Puebla Laboratory of Bacteriology Instituto Butantan Departamento de Microbiologia e Imunologia Instituto de Biociencias da UNESP