Simultaneous Detection of Caga and Cage of Helicobacter pylori Strains Recovered from Iranian Patients with Different Gastroduodenal Diseases

Abstract

Background: To asses the status of two representative genes of cag PAI i.e cagA and cagE of Helicobacter pylori strains infecting Iranian patients suffered from various clinical outcomes using one-step PCR.
Methods: A total of 120 H. pylori infected patients including non-ulcer dyspepsia, NUD (n=81), peptic ulcer disease, PUD (n=17), and gastric carcinoma, GC (n= 22) referred for endoscopy or gastric resection to AmirAlam Hospital or Cancer Institute from 2005 to 2008 were assessed. The status of cagA and cagE genes was determined by gene specific PCR.
Results: 84.2% and 90.8% of the tested strains were positive for cagA and cage, respectively. 81.7% strains were positive for both cagA and cagE genes, whereas 8 (6.7%) were found double negative. The prevalence of cagA in GC patients (100%) was slightly higher than PUD patients (94.1%). All of GC cases were infected with cagA-positive strains. The same distribution pattern was indicated for cagE gene in GC and PUD patients. The cagA-positive strains were significantly associated with GC as compared with NUD (P< 0.05) but this association did not gain statistical significance when cagE gene was assessed.
Conclusion: The concurrent detection of cagA/cagE genes allowed rapid and specific clarification of cag PAI status. The strains with cagA/cagE genotype are predominant in Iran regardless of clinical outcome and create a distinct cluster pattern from those in the West and similar to those of East Asian countries. The current study also demonstrated that cagE gene can be explored as a better indication of cag-PAI in Iranian H. pylori strains.