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Comparative analysis of isolates belonging to the O3:H2 serotype isolated from different sites of infeccion, and evaluation of the role of AAF/I in the urothelial cells infeccion

Grant number: 23/10536-7
Support Opportunities:Scholarships in Brazil - Master
Effective date (Start): December 01, 2023
Effective date (End): April 30, 2025
Field of knowledge:Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
Principal Investigator:Rodrigo Tavanelli Hernandes
Grantee:Bruna Mendes Luiz
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


Pathogenic Escherichia coli isolates can lead to intestinal infections, caused by Diarrheagenic E. coli (DEC), or outside the gastrointestinal tract, caused by Extraintestinal Pathogenic E. coli (ExPEC). Among DEC pathotypes, enteroaggregative E. coli (EAEC) is frequently isolated from cases of acute and persistent diarrhea in children and adults in Brazil. EAEC isolates are identified by the adhesion on HeLa and HEp-2 cells in an arrangement resembling "stacked bricks", called aggregative adherence pattern (AA). This pattern is associated with the presence of aggregative adherence fimbriae (AAFs), currently described in five distinct variants (AAF/I-AAF/V). Outside the gastrointestinal tract, isolates of uropathogenic E. coli (UPEC) are among the main agents implicated in urinary tract infections (UTIs), accounting for up to 95% of cases. EAEC isolates obtained from UTI cases have been reported as UPEC/EAEC hybrids in recent studies. In a recent study by our laboratory, EAEC markers such as the aggR and aatA genes were detected in four isolates obtained from patients symptomatic for ITUs; one of these isolates belonged to serotype O3:H2; this serotype has been frequently isolated from samples of feces from children with and without diarrhea. It is of great importance to investigate these hybrids, trying to understand their origins, which virulence genes are present, and how these genes can contribute to the success of UTIs. The objective of this study is to carry out a comparative genomic analysis of the UPEC-34 isolate, serotype O3:H2, obtained from ITU, with E. coli isolates from the same serotype, obtained from children with or without diarrhea. In addition, UPEC-34 will be submitted to mutagenesis and complementation assays with the aggDCBA operon, with the aim of evaluating the influence of AAF/I on adhesion to urothelial cell line 5637 and biofilm production. Furthermore, other differently detected genomic regions in isolates of serotype O3:H2 showing association with adhesion to cells may be further included in this analysis. It is expected to understand the characteristics of EAEC isolates obtained from UTI, as well as to evaluate the role of AAF/I, and other possible structures related to EAEC and/or UPEC, in urinary tract infection.

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