Role of the YehD fimbriae in the virulence-associated properties of enteroaggregative Escherichia coli |
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| Authors: | Jorge Soria-Bustos Waleska Saitz Abraham Medrano Cristina Lara-Ochoa Zineb Bennis Valerio Monteiro-Neto Camilla Itapary dos Santos Josias Rodrigues Rodrigo T Hernandes Jorge A Yáñez Javier Torres Fernando Navarro-García Ygnacio Martínez-Laguna Roxane M Fontes Piazza Danielle Dias Munhoz María L Cedillo Miguel A Ares Miguel A De la Cruz James P Nataro Jorge A Girón |
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| Institution: | 1. Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA;2. Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico;3. University of Florida, Emerging Pathogens Institute, Gainesville, FL, USA;4. Departamento de Patologia, Universidade Federal do Maranhão, São Luís, MA, Brazil;5. Departamento de Microbiologia e Imunologia, Instituto de Biociencias da UNESP, Botucatu, SP, Brazil;6. Facultad de Estomatología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico;7. Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano de Seguro Social, Ciudad de México, Mexico;8. Departamento de Biología Celular, Centro de Investigaciones Avanzadas, Instituto Politécnico Nacional, Ciudad de México, Mexico;9. Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico;10. Laboratory of Bacteriology, Instituto Butantan, Butantan, São Paulo, Brazil |
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| Abstract: | 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 Y ehD f imbriae (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. |
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