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The heterogeneic distribution of Helicobacter pylori cag pathogenicity island reflects different pathologies in
Alfizah Hanafiah1, Shaza Azlin Razak1, Hui-Min Neoh2
1Universiti Kebangsaan Malaysia, Faculty of Medicine, Dept. of Medical Microbiology and Immunology, Kuala Lumpur, Malaysia.
Background:
Helicobacter pylori harbouring cag-pathogenicity island (cagPAI) which encodes type IV secretion system (T4SS) and cagA virulence gene are involved in inflammation of the gastric mucosa. We examined all the 27 cagPAI genes in 88 H. pylori isolates from patients of different ethnicities and examined the association of the intactness of cagPAI region with histopathological scores of the gastric mucosa.
Results:
96.6% (n=85) of H. pylori isolates were cagPAI-positive with 22.4% (19/85) having an intact cagPAI, whereas 77.6% (66/85) had a partial/rearranged cagPAI. The frequency of cag2 and cag14 were found to be significantly higher in H. pylori isolated from Malays, whereas cag4 was predominantly found in Chinese isolates. The cag24 was significantly found in higher proportions in Malay and Indian isolates than in Chinese isolates. The intactness of cagPAI region showed an association with histopathological scores of the gastric mucosa. Significant association was observed between H. pylori harbouring partial cagPAI with higher density of bacteria and neutrophil activity, whereas strains lacking cagPAI were associated with higher inflammatory score.
Conclusions:
The genotypes of H. pylori strains with various cagPAI rearrangement associated with patients' ethnicities and histopathological scores might contribute to the pathogenesis of H. pylori infection in a multi-ethnic population.
Insights
The cag-pathogenicity island (cagPAI) in Helicobacter pylori shows variations linked to ethnicity and gastric inflammation. Rearranged cagPAI is associated with higher bacterial density and neutrophil activity, impacting H. pylori pathogenesis.
Area of Science:
- Microbiology
- Gastroenterology
- Genetics
Background:
- Helicobacter pylori infection is a major cause of gastric inflammation.
- The cag-pathogenicity island (cagPAI) and its encoded type IV secretion system (T4SS) are key virulence factors.
- CagA is a significant virulence gene within the cagPAI, contributing to gastric pathology.
Purpose of the Study:
- To investigate the genetic makeup of the cagPAI in H. pylori isolates from diverse ethnic groups.
- To determine the association between cagPAI integrity and the histopathological severity of gastric mucosa.
Main Methods:
- Analysis of all 27 cagPAI genes in 88 H. pylori isolates.
- Correlation of cagPAI gene presence and intactness with patient ethnicity.
- Assessment of histopathological scores in gastric biopsies.
Main Results:
- 96.6% of isolates were cagPAI-positive; only 22.4% had an intact cagPAI, with most being partial/rearranged.
- Specific cagPAI genes (cag2, cag14, cag4, cag24) showed ethnic associations (Malay, Chinese, Indian).
- Intactness of the cagPAI region correlated with gastric histopathological scores, with partial cagPAI linked to higher bacterial density and neutrophil activity.
Conclusions:
- H. pylori cagPAI genotypes and rearrangements are associated with host ethnicity.
- These variations influence the pathogenesis of H. pylori infection in multi-ethnic populations.
- Understanding cagPAI diversity is crucial for deciphering H. pylori-associated gastric diseases.
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