The role of mixed infections with Helicobacter pylori in gastric pathologies from a Colombian population

Multiple infections with the bacterium Helicobacter pylori have shown to reduce the cytotoxic effects of the Oncogenic Toxin CagA in vitro. Here we determined, through a cross-sectional study, the frequency of multiple infections with Type I and Type II strains, together with bacterial load, bacterial tropism, pathogenicity markers and neutrophil infiltration, to determine the relevance of mixed infections in the severity of gastric pathologies. Gastric biopsies from 342 symptomatic patients were collected from antrum and corpus, and their infection status determined through RUT, culture and histology. The CagA status of approx. 100 strains per patient was determined, and bacterial load (cfu/g). Severity of gastric pathologies were determined through endoscopy evaluation and histological analysis. Bacteria from each type of infection (mixed, type I and type II) were evaluated in their capacity of CagA translocation, IL-8 induction levels and induction of resistance to CagA translocation in co- and pre-infection assays. For statistical evaluation multivariate multiple regression, a linear model and Wilcoxon test were used. Population presented a H. pylori prevalence of 29,82%, 61% of patients presented infections with Type I (CagA(+)) and Type II (CagA(-)) strains (mixed infections), 23.17% with only Type I and 15.85% only Type II. The type of infection neither altered the bacterial load in patients, nor seems to determine the severity of the pathology. In mixed infections, the bacteria showed no tropism. In vitro assay with strains from mixed patients showed the capability to reduce the CagA translocation in epithelial like cells. Type I strains originated from mixed infections induce less IL-8 than Type I strains originated from patients presenting only type I strains. Here we show that the status of mixed infections is the most prevalent in this population, and that type I strains have adapted to induce less IL-8 when co-habiting with type II strains.--Tomado del Formato de Documento de Grado

• Autores: Rojas Rengifo, Diana Fabiola
• Tipo de recurso: Doctoral thesis
• Fecha de publicación: 2018
• Institución: Universidad de los Andes
• Repositorio: Séneca: repositorio Uniandes
• Idioma: eng
• OAI Identifier: oai:repositorio.uniandes.edu.co:1992/38736
• Acceso en línea: http://hdl.handle.net/1992/38736
• Palabra clave: Helicobacter pylori - Toxinas - Investigaciones; Translocación (Genética) - Investigaciones - Estudio de casos; Histología - Investigaciones - Estudio de casos; Patología - Investigaciones - Estudio de casos; Biología
• Rights: openAccess
• License: http://creativecommons.org/licenses/by-nc-sa/4.0/