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PCR for identification and typing of Helicobacter pylori isolated from children
D Dzierzanowska1, A Gzyl, E Rozynek
1Department of Clinical Microbiology, Children's Memorial Health Institute, Warsaw, Poland.
Insights
This study utilized advanced molecular techniques, including PCR and genetic typing, to detect Helicobacter pylori (H. pylori) in children. Results highlight the prevalence of H. pylori and its Cag A gene in pediatric gastroduodenal diseases.
Area of Science:
- Pediatric Gastroenterology
- Microbiology
- Molecular Diagnostics
Background:
- Upper gastroduodenal diseases in children are often linked to Helicobacter pylori (H. pylori) infections.
- Accurate detection and characterization of H. pylori are crucial for effective management.
Purpose of the Study:
- To evaluate the efficacy of various detection methods for H. pylori in pediatric biopsy specimens.
- To characterize H. pylori strains, including the presence of Cag A and genetic diversity, in children with gastroduodenal conditions.
Main Methods:
- Gastric biopsy specimens from 191 children were analyzed using culture, Gram staining, histology, and PCR.
- PCR targeted urease A/B genes and Cag A gene.
- H. pylori strains were genetically typed using PCR-RFLP and RAPD analysis.
Main Results:
- H. pylori was detected in 52% of gastritis and 50% of duodenal ulcer cases via culture and PCR.
- An additional 18.1% (gastritis) and 12.5% (duodenal ulcer) were PCR positive only.
- 70.8% of isolated H. pylori strains were Cag A positive.
- RAPD typing demonstrated superior discrimination power compared to PCR-RFLP for strain differentiation.
Conclusions:
- Molecular methods like PCR enhance H. pylori detection rates in pediatric gastroduodenal diseases.
- Genetic typing aids in understanding H. pylori epidemiology and differentiating infection sources.
- RAPD is a powerful tool for molecular typing of H. pylori in clinical settings.
Abstract:
From 191 children with upper gastroduodenal disease 236 gastric biopsy specimens were taken. H. pylori was detected by use of culture Gram staining histological examination and PCR technique. A segment of DNA coding protein synthesis of 26 kDa or urease A and B gene were used for PCR amplification. PCR technique was also used for determination of the presence of Cag A gene in 72 strains of H. pylori isolated from children. Genetic typing of H. pylori strains by RFLP analysis of PCR amplified urease B gene 933 bp fragment and RAPD were performed. Biopsy specimens taken from children with gastritis were in 52% H. pylori culture and PCR positive, while 18.1% PCR positive only. Similarly, specimens taken from children with duodenal ulcer were in 50% H. pylori culture and PCR positive, while 12.5% PCR positive only. Fifty one (70.8%) from 72 strains of H. pylori were Cag A positive. Molecular typing of the strains isolated during first and follow-up endoscopy allowed the differentiation between reinfection or new infection and coinfection. It was shown that RAPD typing had better discrimination power in comparison to PCR--RFLP method.