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Conservation of the cag pathogenicity island is associated with vacA alleles and gastroduodenal disease in South African Helicobacter pylori isolates

  • 0GI Clinic and Department of Medicine, University of Cape Town and Groote Schuur Hospital, Cape Town, South Africa.
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June 20, 2001

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June 20, 2001

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Summary

This summary is machine-generated.

The Helicobacter pylori cag pathogenicity island (cagPAI) structure is linked to disease severity in South Africa. Intact cagPAI and specific vacA alleles correlate with peptic ulcers and gastric cancer, while deletions are linked to gastritis.

Area Of Science

  • Microbiology
  • Genetics
  • Gastroenterology

Background

  • The vacuolating cytotoxin gene (vacA) s1 genotype is associated with severe disease in South African Helicobacter pylori infections.
  • The cytotoxin associated gene cagA is present in over 95% of South African isolates and serves as a marker for the cag pathogenicity island (cagPAI).

Purpose Of The Study

  • To characterize the cagPAI in South African H. pylori isolates.
  • To determine if structural variations in the cagPAI correlate with vacA status and clinical outcomes.

Main Methods

  • Polymerase chain reaction (PCR) was used to analyze 109 H. pylori strains.
  • Strains were sourced from patients with peptic ulceration, gastric adenocarcinoma, and gastritis alone.
  • Analysis focused on selected cagPAI genes and vacA alleles.

Main Results

  • All 109 strains were positive for cagA.
  • An intact cagPAI was found in 60% of isolates, significantly more common in peptic ulcer (78%) and gastric adenocarcinoma (73%) cases compared to gastritis alone (40%).
  • The vacA s1 and m1 alleles showed a strong association with an intact cagPAI.

Conclusions

  • While a complete cagPAI is common, deletions in its 5' region are linked to gastritis alone.
  • These deletions also correlate with the non-cytotoxic vacA s2/m2 genotype, suggesting a role in disease progression.

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