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Comparison of three methods: culture, real-time PCR and fluorescent in situ hybridisation in detecting of Helicobacter pylori

Abstract number: P1983

Ozcakir O., Yonem O., Demir H., Altinbas A., Altinok G., Orhan D., Uner A., Akyon Y.

Objectives:H. pylori is one of the most common bacterial pathogens in humans. It causes chronic gastritis, peptic ulcer disease and it is a major risk factor for gastric cancer. Detection of this pathogen with accurate methods is very important.

Aim: to compare H. pylori detection in gastric biopsy specimens by culture, Real-Time PCR and FISH.

Methods: Biopsy specimens of 148 patients, with dyspeptic complaints were examined. Culture was performed on Brain Heart Infusion agar, for Real-Time PCR examination, chromosomal DNA was extracted by Cetryl-trimethl-ammonium bromide method and the assay was performed on Light Cycler (Roche Diagnostics, Germany). Melting peaks of 650C (± 2.00C) showed the detection of H. pylori in the sample. For FISH examination formalin-fixed paraffin-embedded gastric biopsies were sectioned. The sections were hybridised using the commercially available test system seaFast H. pylori Combi-Kit (Theranostics International, Netherlands) according to the manufacturer's instructions. Four different sections were examined to give a negative result.

Results: Among 148 samples 70 were positive by culture, 118 were positive by PCR and 124 were positive by FISH. Among the 124 samples determined positive by FISH; 98 were determined positive in the first section, 17 were determined positive in the second section and 9 were determined positive in the third section. Culture, PCR and FISH results were all positive for 63 samples and negative for 24 samples. 54 samples were culture negative, but PCR and FISH positive. 7 samples were PCR negative, but culture and FISH positive.

Conclusion: At least two tests are essential for H. pylori determination. Culture, because of contamination and the difficulties of culturing of H. pylori, has false negative results. However culturing must be performed, hence antimicrobial susceptibility testing is essential. Among the three methods Real-Time PCR has more capability to determine the positive results in the first sample, therefore it is easier to perform in routine laboratory practice.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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