Diagnostic performance between histopathological and molecular methods in the detection of Helicobacter pylori / Desempenho diagnóstico entre os métodos istopatológico e molecular na detecção de Helicobacter pylori

ABSTRACT Introduction: Helicobacter pylori (H. pylori) is a Gram negative bacterium considered to be the etiologic agent of various gastric diseases. The prevalence of bacterial infection varies according to age, geographic location, ethnicity and socioeconomic status. The chronic infection caused by microorganism can favor the development of severe pathologies such as gastric adenocarcinoma. In this sense, early diagnosis is essential for a better prognosis and therapeutic success. Several diagnostic methods performed using invasive and non-invasive techniques, with different sensitivity and specificity, have been used in the detection of H. pylori. Objective: To compare the performance of the molecular and histopathological technique used in the diagnosis of H. pylori infection. Methods: 76 gastric tissue samples were collected from dyspeptic patients who underwent molecular and histopathological diagnosis. Molecular detection was performed using the ribosomal gene (16S rRNA) using the polymerase chain reaction (PCR) technique. Results: The PCR-based molecular diagnostic method detected the bacterium in 63.1% of the samples, while the histopathological test identified the microorganism in only 38.1% of gastric biopsies. The data demonstrated that the PCR technique was about 1.6 times more sensitive than the histopathological technique. Conclusion: The PCR technique was the most efficient diagnostic method for detecting H. pylori and can be implemented in the laboratory routine as a complementary test for the early detection of H. pylori.

RESUMEN Introducción: Helicobacter pylori (H. pylori) es una bacteria Gram negativa considerada agente etiológico de diversas enfermedades gástricas. La prevalencia de la infección bacteriana varía según la edad, la ubicación geográfica, la etnia y el nivel socioeconómico. La infección crónica provocada por esos microorganismos puede favorecer el desarrollo de patologías graves como el adenocarcinoma gástrico. Por esa razón, el diagnóstico precoz es fundamental para un mejor pronóstico y éxito terapéutico. En la detección de H. pylori se han utilizado varios métodos de diagnóstico realizados mediante técnicas invasivas y no invasivas, con diferentes sensibilidad y especificidad. Objetivo: Comparar el desempeño de las técnicas moleculares e histopatológicas utilizadas en el diagnóstico de la infección por H. pylori. Métodos: Se recolectaron 76 muestras de tejido gástrico de pacientes dispépticos y se las sometieron a diagnóstico molecular e histopatológico. La detección molecular se realizó mediante el gen ribosómico (ARNr 16S) mediante la técnica de reacción en cadena de la polimerasa (PCR). Resultados: El método molecular de diagnóstico basado en PCR detectó la bacteria en el 63,1% de las muestras, mientras que la prueba histopatológica identificó el microorganismo en solo el 38,1% de las biopsias gástricas. Los datos demostraron que la técnica de PCR era aproximadamente 1,6 veces más sensible que la técnica histopatológica. Conclusión: La técnica de PCR fue el método diagnóstico más eficaz para la detección de H. pylori y puede implementarse en la rutina del laboratorio como prueba complementaria para la detección precoz de H. pylori.

RESUMO Introdução: Helicobacter pylori (H. pylori) é uma bactéria Gram negativa considerada o agente etiológico de várias doenças gástricas. A prevalência da infecção bacteriana varia de acordo com idade, localização geográfica, etnia e status socioeconômico. A infecção crônica ocasionada por esse microrganismo pode favorecer o desenvolvimento de patologias severas, como o adenocarcinoma gástrico. Nesse sentido, o diagnóstico precoce é essencial para um melhor prognóstico e o sucesso terapêutico. Vários métodos de diagnóstico realizados com técnicas invasivas e não invasivas, com diferentes sensibilidade e especificidade, têm sido utilizados na detecção de H. pylori. Objetivo: Comparar o desempenho das técnicas molecular e histopatológica utilizadas no diagnóstico da infecção por H. pylori. Métodos: Setenta e seis amostras de tecido gástrico foram coletadas de pacientes dispépticos e submetidas ao diagnóstico molecular e histopatológico. A detecção molecular foi realizada utilizando o gene ribossomal (rRNA 16S) por meio da técnica de reação em cadeia da polimerase (PCR). Resultados: O método molecular de diagnóstico com base na PCR detectou a bactéria em 63,1% das amostras, enquanto o teste histopatológico identificou o microrganismo em apenas 38,1% das biópsias gástricas. Os dados demonstram que a técnica de PCR apresentou cerca de 1,6 vezes mais sensibilidade que a técnica histopatológica. Conclusão: A técnica de PCR foi o método de diagnóstico mais eficiente para detecção de H. pylori e pode ser implementada na rotina laboratorial como teste complementar para detecção precoce de H. pylori.

Genomics and epidemiology for gastric adenocarcinomas (GE4GAC): a Brazilian initiative to study gastric cancer

Gastric cancer (GC) is the fifth most common type of cancer worldwide with high incidences in Asia, Central, and South American countries. This patchy distribution means that GC studies are neglected by large research centers from developed countries. The need for further understanding of this complex disease, including the local importance of epidemiological factors and the rich ancestral admixture found in Brazil, stimulated the implementation of the GE4GAC project. GE4GAC aims to embrace epidemiological, clinical, molecular and microbiological data from Brazilian controls and patients with malignant and pre-malignant gastric disease. In this letter, we summarize the main goals of the project, including subject and sample accrual and current findings

Assessment of safety and feasibility of a new technical variant of gastropexy for percutaneous endoscopic gastrostomy: an experience with 435 cases.

BACKGROUND: Percutaneous Endoscopic Gastrostomy (PEG) performed through the Introducer Technique is associated with lower risk of surgical infection when compared to the Pull Technique. Its use is less widespread as the fixation of the stomach to the abdominal wall is a stage of the procedure that is difficult to be performed. We present a new technical variant of gastropexy which is fast and easy to be performed. The aim of this study was to evaluate the safety and feasibility of a new technical variant of gastropexy in patients submitted to gastrostomy performed through the Introducer Technique. METHODS: All the patients submitted to PEG through the Introducer Technique were evaluated using a new technical variant of gastropexy, which consists of two parallel stitches of trasfixation sutures involving the abdominal wall and the gastric wall, performed with a long curved needle. Prophylactic antibiotics were not used. Demographic aspects, initial diagnosis, indication, sedation doses, morbidity and surgical mortality were all analyzed. RESULTS: Four hundred and thirty-five consecutive PEGs performed between June 2004 and May 2007 were studied. Nearly all the cases consisted of patients presenting malignant neoplasia, 79.5% of which sited in the head and neck. The main indication of PEG was dysphagia, found in 346 patients (79.5%). There were 12 complications (2.8%) in 11 patients, from which only one patient had peristomal infection (0.2%). There was one death related to the procedure. CONCLUSION: Gastropexy with the technical variant described here is easy to be performed and was feasible and safe in the present study. PEG performed by the Introducer Technique with this type of gastropexy was associated with low rates of wound infection even without the use of prophylactic antibiotics.