Evaluation of the co-production of distinct known diarrheagenic Escherichia coli adhesins and a novel autotransporter adhesin identified in atypical enteropathogenic E. coli of serotype O2:H16

• Grant number: 21/12754-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2022
• End date: August 31, 2022
• 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

Escherichia coli adherence to epithelial cells and abiotic surfaces is a multifactorial phenotype that involves the coordinate action of both fimbrial and afimbrial adhesins. Enteropathogenic (EPEC) and enteroaggregative (EAEC) E. coli are diarrheagenic E. coli pathotypes most frequently isolated in epidemiological studies carried out in Brazil and in several other countries. Due to this, many studies have been focused into discover the adhesins responsible for localized (LA), localized-like (LA-like) adherence patterns observed in typical (tEPEC) and atypical (aEPEC) isolates, respectively; as well as the adhesins responsible for the aggregative pattern (AA) in EAEC. One of the first phenotypic features described in tEPEC isolates was the LA, which is mediated by a type IV fimbria known as bundle-forming pilus (BFP). Both tEPEC and aEPEC produce a histopathological lesion in infected epithelial cells that is termed attaching and effacing (AE), whose intimate adherence of the bacteria to the epithelial cell is mediated by the interaction of the adhesin intimin to its translocated receptor Tir (Translocated intimin receptor). On the other hand, EAEC isolates produce an adherence pattern characterized by organization of the bacteria cells in a stacked brick like arrangement (AA pattern), which is mediated by the production of one of the five aggregative adhesion adhesins (AAF) described so far. Very recently, our laboratory identified a new autotransporter adhesin (ATA), Type V secretion system, in aEPEC isolates of serotype O2:H16. Preliminary data have shown the involvement of this new ATA in the bacterial autoaggregation phenotype. The main objective of this study is to evaluate the effect of co-production of the new ATA with well-characterized adhesins of the EPEC (Intimin and BFP) and EAEC (AAF/I - AAF/V and AFP) pathotypes on bacterial autoaggregation and biofilm formation on abiotic surfaces phenotypes.