Chain-like adherence (CLA): an adherence pattern produced by enteroaggregative Escherichia coli (EAEC) and mediated by the aggregative adherence fimbria IV (AAF/IV)?

• Grant number: 24/06044-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2024
• End date: June 30, 2026
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Rodrigo Tavanelli Hernandes
• Grantee: Guilherme Frizzarin Ramalhães de Souza
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated research grant: 17/14821-7 - Exploring novel virulence strategies in Escherichia coli, AP.TEM

Abstract

Bacterial adherence to epithelial cells is an indispensable step in the pathogenicity, allowing the establishment of several pathogens in their hosts. Among the bacteria causing infections in the gastrointestinal tract, we can highlight the enteroaggregative Escherichia coli (EAEC) as an important agent of acute and persistent diarrhea. The main phenotypic feature of EAEC isolates is their ability to adhere to cells in a pattern resembling a stacked brick wall, named aggregative adhesion pattern (AA), and mainly mediated by the five aggregative adherence fimbriae (AAF/I - AAF/V) variants. However, some EAEC isolates are able to form cord-like structures or chains when in contact with epithelial cells, being this phenotype called Chain-like adherence (CLA). Interestingly, studies conducted by our research group have pointed out to a close association between certain EAEC isolates (phylogroup B1 and H19), carrying the AAF/IV pilin-encoding gene (agg4A), and the CLA pattern production. Nonetheless, agg4A+ EAEC isolates from phylogroup D and H18 produce the AA pattern, constituting, therefore, two phylogenetically distinct groups. Considering this scenario, our objective is to sequence agg4A+ EAEC isolates trying to establish a panel of similarities and divergences between the isolates producing CLA or AA patterns. In order to investigate the role of AAF/IV in the establishment of the CLA pattern, mutants in the agg4DCBA operon will be constructed and evaluated in cultured epithelial cell interaction assays. In summary, our project aims to establish the association between AAF/IV and the CLA pattern, as well as to investigate the existence of novel potential adhesive structures that may participate in the establishment of this phenotype.