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Características del microbioma gástrico e intestinal en relación al estado de Helicobacter pylori en una población pediátrica
Gut and gastric microbiota characteristics in relation to Helicobacter pylori status in a pediatric population

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Llorca Otero, Laura (2017) Características del microbioma gástrico e intestinal en relación al estado de Helicobacter pylori en una población pediátrica. [Thesis]

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Abstract

Introducción. H. pylorí es una bacteria Gram negativa con forma de espiral, que coloniza el estómago humano de aproximadamente 50% de la población mundial. La infección por H. pylorí está estrechamente asociada con la aparición de gastritis crónica, úlcera péptica, y el desarrollo de cáncer gástrico. La colonización estable de H. pylorí en el estómago sugiere que otras bacterias también pueden haber sido capaces de adaptarse al entorno ácido del estómago. Las nuevas tecnologías de secuenciación de ADN nos permiten entender mejor la composición de nuestro microbioma. El objetivo principal de este estudio es caracterizar y comparar la microbiota gástrica e intestinal en pacientes pediátricos infectados o no por H. pylorí. Métodos Se estudiaron 51 niños que fueron sometidos a endoscopia digestiva alta debido a síntomas dispépticos (18 H. pylorí positivos y 33 negativos). Se obtuvieron biopsias gástricas y un exudado rectal. En las biopsias gástricas se realizaron los siguientes métodos: test rápido de ureasa, cultivo, examen histológico y qPCR (16S ARNr específico de H. pylorí). Se realizó una PCR a tiempo real para determinar la concentración de bacterias totales en ambos tipos de muestras. Por otra parte, se preparó una librería de amplicones a partir de cada muestra y se estudió el microbioma gástrico e intestinal mediante secuenciación de alto rendimiento de la región V4 del gen 16S ARNr...

Resumen (otros idiomas)

Introduction. H. pylori is a microaerobic, Gram negative spiral bacterium that colonizes the human stomach of approximately 50% of the world's population. H. pylori infection is closely associated with chronic gastritis, peptic ulcer disease, and development of gastric cancer. H. pylori usually do not cause clinical problems in the paediatric population, and only a small proportion of children develop nonspecific symptoms such as vomiting, nausea, loss of weight, haematemesis, decreased appetite, etc. that may be associated with H. pylori infection. Nevertheless, infection with this bacteria is recognized as a cause of gastritis and peptic ulcer disease in children. The stable colonization of H. pylori in the stomach suggests that other bacteria may also have been able to adapt to the acidic environment of the stomach. Traditionally, microbiota study was performed using culture techniques although the bacteria that can be grown are only a small fraction of the total number of bacteria present. Nowadays, new DNA sequencing technologies allow us to better understand the composition of our micro biome. The main goal of this study is to compare the gastric and intestinal microbiota i n pediatric patients infected or not by H. pylori. Methods. We studied 51 children that underwent gastric endoscopy due to dyspeptic symptoms (18 H. pylori positive and 33 negative). Mean age of this patients was 11.1 years (range: 1-17). Gastric biopsies and rectal swabs were obtained. In gastric biopsies the following methods were performed: Rapid Urease Test, culture (blood and pylori agar plates), histological exam and qPCR (specific 16S H. pylori rRNA in LightCycler®480). DNA was extracted from biopsy using Ultraclean Tissue & Cells DNA Isolation Kit (MoBio) and from rectal swab by using PowerLyzerTM PowerSoil DNA Isolation Kit (MoBio). Afterwards, real time PCR was performed to determine total bacteria concentration in both gastric biopsies and rectal exudates. On the other hand, a library was prepared from each specimen and gastric and intestinal microbiome were studied by V4-16S rRNA high-throughput sequencing using the MISeq Illumina platform. Alfa and beta diversity was studied by QIIME software, taxonomic assignments were performed with the Ribosomal Database Project classifier (RDP classifier) and LEfSe and PICRUSt algorithms were performed with the online interface Galaxy...

Item Type:Thesis
Additional Information:

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Microbiología II, leída el 31/03/2016

Directors:
DirectorsDirector email
Alarcón Rivero, Teresa
López-Brea Calvo, Manuel
Gómez Alférez, Ángela
Uncontrolled Keywords:Infecciones por helicobacter pylori
Palabras clave (otros idiomas):Helicobacter pylori infections
Subjects:Medical sciences > Medicine > Gastroenterology and Hepatology
Medical sciences > Pharmacy > Microbiology
ID Code:43912
Deposited On:14 Jul 2017 11:15
Last Modified:14 Jul 2017 11:15

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