ORIGINAL RESEARCH article
Front. Cell. Infect. Microbiol.
Sec. Bacteria and Host
Volume 15 - 2025 | doi: 10.3389/fcimb.2025.1617101
EPEC Autotransporter Adhesin (Eaa): A novel adhesin identified in atypical enteropathogenic Escherichia coli
Provisionally accepted- 1Universidade Estadual Paulista (UNESP) - Instituto de Biociências, Botucatu, Brazil
- 2Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Rio Grande do Sul, Brazil
- 3School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
- 4Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, Brazil
- 5Institute for Genome Sciences, Department of Microbiology and Immunology, Department of Microbial Pathogenesis, Center for Pathogen Research, School of Medicine, University of Maryland, Baltimore, Maryland, United States
- 6Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, Australia
- 7Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
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Enteropathogenic Escherichia coli (EPEC) is a pathogen that causes diarrhea that can be subdivided into typical (tEPEC) and atypical (aEPEC), based on the production of an adhesin termed Bundle-Forming Pilus (BFP) in the former group. aEPEC is one of the main bacterial pathogens isolated from individuals with diarrhea, and some serotypes have been implicated in diarrheal outbreaks in Brazil, such as the O2:H16. A comparative genomic analysis of aEPEC of this serotype led to the identification of a gene encoding a previously uncharacterized autotransporter protein. In the present study, this novel autotransporter protein was characterized and named EPEC Autotransporter Adhesin (Eaa). The Eaa-encoding gene (eaa) is located in a chromosomal prophage region of 17,014 base pairs, organized in 20 open reading frames and inserted downstream to the threonine-tRNA. A recombinant plasmid termed pIC (pBAD/Myc-His A harboring the eaa gene from aEPEC BA92) was transformed in the MS427 host bacteria, and the MS427(pIC) was used in phenotypic assays. Immunogold-labelling transmission electron microscopy, using anti-Eaa antibodies, showed the presence of Eaa in the cell surface of the wild-type BA92 and MS427(pIC) strains. Subsequently, we demonstrated that Eaa mediates bacterial autoaggregation, biofilm formation and binding to several components of the extracellular matrix, including fibrinogen, plasma and cellular fibronectin, type I, III as well as V collagen and laminin. In summary, we demonstrated that Eaa harbors several adherence properties and may contribute to the pathogenicity of some aEPEC isolates by mediating the interaction of this pathogen with biotic and abiotic surfaces.
Keywords: Autotransporter protein, adhesin, atypical EPEC, Bacterial Pathogenesis, Biofilm, fibronectin
Received: 23 Apr 2025; Accepted: 21 Jul 2025.
Copyright: © 2025 Orsi, de Lira, Castilho, De Souza, Onur, Chura-Chambi, Abe, Carvalho, Dos Santos, Rasko, Schembri, Barbosa, Elias and Hernandes. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Waldir P Elias, Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Rio Grande do Sul, Brazil
Rodrigo T. Hernandes, Universidade Estadual Paulista (UNESP) - Instituto de Biociências, Botucatu, Brazil
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