Frequency of adhesin-encoding genes and their association with the aggregative adherence pattern (AA) and biofilm formation phenotypes in enteroaggregative Escherichia coli (EAEC)

• Grant number: 23/04219-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2023
• End date: December 31, 2023
• Field of knowledge: Health Sciences - Collective Health - Public Health
• Principal Investigator: Rodrigo Tavanelli Hernandes
• Grantee: Gustavo Boldrim Bueno
• 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

Enteroaggregative Escherichia coli (EAEC) is an important agent of diarrheal disease affecting both children and adults. The main characteristics of this pathogen are their ability to adhere to epithelial cells in a characteristic pattern termed aggregative adherence pattern (AA), which is characterized by the organization of bacteria in a way that resembles stacked bricks, and its high efficiency to form biofilms on abiotic surfaces. These phenotypic characteristics are associated with the presence of a chaperone-usher type fimbria called aggregative adhesion fimbria (AAF), of which we currently know five distinct variants (AAF/I - AAF/V). However, recently a type IV fimbriae, termed aggregate-forming pili (AFP), was identified as being responsible for mediating the formation of the AA pattern in a hybrid Shiga toxin-producing/enteroaggregative E. coli (STEC/EAEC) isolate, and its role for colonization of both the gastrointestinal and the genitourinary tracts was confirmed in an uropathogenic E. coli (UPEC) isolate harboring EAEC markers. In addition, it was observed that some EAEC isolates devoid of the genes responsible for encoding the AAFs, as well as AFP can harbor an operon formed by four genes that would potentially encode a non-fimbrial adhesin, termed CS22, described in an enterotoxigenic E. coli (ETEC) isolate. Given the recent discoveries of AFP and the CS22 operon in EAEC isolates, little is known about the genetic backgrounds of E. coli where these adhesins occur, and their association with adherence and biofilm formation phenotypes. Therefore, the present study aims to molecularly and phenotypically characterize a collection of EAEC to better understand the frequency of the distinct adhesins, as well as their relationship with adherence and biofilm formation phenotypes with emphasis on AFP and CS22.