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Complex polysaccharides as PCR inhibitors in feces: Helicobacter pylori model
L Monteiro1, D Bonnemaison, A Vekris
1Laboratoire de Bactériologie, Université de Bordeaux 2, France. helico@labhel.u-bordeaux2.fr
Abstract:
A model was developed to study inhibitors present in feces which prevent the use of PCR for the detection of Helicobacter pylori. A DNA fragment amplified with the same primers as H. pylori was used to spike samples before extraction by a modified QIAamp tissue method. Inhibitors, separated on an Ultrogel AcA44 column, were characterized. Inhibitors in feces are complex polysaccharides possibly originating from vegetable material in the diet.
Insights
Fecal inhibitors hinder Helicobacter pylori detection via PCR. These complex polysaccharides, likely from diet, interfere with DNA amplification, requiring modified extraction methods for accurate results.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Polymerase Chain Reaction (PCR) is crucial for detecting Helicobacter pylori.
- Fecal samples often contain inhibitors that impede PCR-based pathogen detection.
- Understanding these inhibitors is vital for improving diagnostic accuracy.
Purpose of the Study:
- To develop a model for studying fecal inhibitors that interfere with PCR detection of Helicobacter pylori.
- To characterize the nature of these PCR inhibitors in fecal matrices.
Main Methods:
- A model system was created using a DNA fragment amplified with H. pylori primers.
- Samples were spiked with the DNA fragment before DNA extraction using a modified QIAamp tissue method.
- Inhibitors were separated and characterized using an Ultrogel AcA44 column chromatography.
Main Results:
- Fecal inhibitors were successfully modeled and studied.
- The separated inhibitors were characterized as complex polysaccharides.
- These polysaccharides are potentially derived from dietary vegetable matter.
Conclusions:
- Fecal inhibitors impacting H. pylori PCR detection are complex polysaccharides.
- Dietary components, specifically vegetables, may be a source of these inhibitory substances.
- Further research may lead to methods to overcome PCR inhibition in fecal samples.