Detecção da Helicobacter pylori através da técnica de reação em cadeia da polimerase em amostras fecais de crianças da cidade de Belém-Pará

Abstract

The infection for the Helicobacter pylori is one of the most common in humans, it is admitted that is acquired in the childhood and that it is one of the main gastritis causes and peptic ulcer in the adult life. Among the several diagnosis methods for the H. pylori infection, the Polimerase Chain Reaction (PCR) has been showing high sensibility for the detection of this pathogen in gastric, oral and faecal samples. With the objective of standardizing the PCR technique to detect the presence of H. pylori of in stool samples and to compare this method with sorologic diagnosis, we studied a samples of 79 children coming of a seroprevalence study realized in the city Belém-Pará in 2003. The genomic DNA was extracted of the feces through a protocol standardized in this research based on the association of quelator agents and proteinase digestion, followed by a phenol-chloroform procedure. For the DNA amplification it was used primers for the gene 16SrRNA specific for Helicobacter genus and for specific detection of the H. pylori it was used primers for desigend for ureA gene. The visualization of the fragments was performed agarose 2% gels stained with ethidium bromide. The presence of the H. pylori was verified in 69,62% (55/79) of the patients. The comparative analysis between the serologic research and the ureA PCR revealed that the molecular technique presents a better acting in the diagnosis of H. pylori in feces (p = 0,0246). The application of the technique of PCR in children's fecal samples, for being a non invasive highly efficient procedure, can be used for detection of the infection by H. pylori in the laboratorial routine as well as in researches of epidemiologic interest.