Investigating survival to acid and bile stresses in vitro and their implications on the pathogenicity of atypical enteropathogenic Escherichia coli

• Grant number: 24/09164-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2024
• Effective date (End): July 31, 2025
• Field of knowledge: Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
• Principal Investigator: Tânia Aparecida Tardelli Gomes do Amaral
• Grantee: Thais Cristina Gregorio Trindade
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Escherichia coli is a commensal bacterium present in the human intestinal microbiota. However, some strains have evolved by acquiring virulence genes that have turned them into pathogenic strains that can cause diarrhea and various types of extraintestinal infections. Six diarrheagenic pathotypes of E. coli have been described, which are transmitted through person-to-person contact, the fecal-oral route, or ingestion of contaminated food.One specific type of E. coli, known as enteropathogenic E. coli (EPEC), is characterized by the ability to form Attaching and Effacing (AE) lesions in enterocytes, which leads to the destruction of microvilli, resulting in diarrhea and malabsorption of nutrients. EPEC strains can be further categorized into typical (tEPEC) and atypical (aEPEC), respectively based on the presence or absence of the Bundle-forming pilus fimbria . Epidemiological studies have shown an increase in the frequency of isolated aEPEC, including those found in both diarrheic and non-diarrheic patients. Genotypic and phenotypic analyses indicated that aEPECs constitute a heterogeneous group, with pathogenic strains and strains unable to cause diarrhea due to defects in virulence genes.Therefore, the objective of this study is to evaluate whether the acidic conditions of the stomach and the bile stress that occurs in the duodenum reduce the survival and affect the adhesion efficiency and ability to form AE lesions of aEPEC that survive these environments.