Vacuolating cytotoxin activity and cagA gene of helicobacter pylori Isolates form peptic ulcer and non-ulcer dyspepsia patients from Thailand

Abstract

The virulence factors of Helicobacter pylori have been associated with clinical presentation and exhibited distinct geographic distribution. In this study, a total of 77 patients were classified at the time of endoscopy as having peptic ulcer diseases (PUD) in 53.2% (41/77), and non-ulcer dyspepsia (NUD) in 46.8% (36/77). All H. pylori tested strains were positive for cagA using PCR. Theprevalence of H. pylori harbouring cytotoxin associated gene A (cagA) in PUD and NUD patients was not significantly diferebt (p>0.05). In addition, 57.7% (41/71) of H. pylori isolates produced vacuolating cytotoxin gene A (VacA) by vacuolization assay in HeLa cell line. No difference in prevalence of VacA producing H. pylori strains was found in PUD (51.5% 24/38) and NUD (63.2%; 17/33) patients (p>0.05). Spearman’s rank correlation test showed no statistical correlation between VacA activity titer and disease status (p>0.05). The results of cagA and VacA in this study were categorized H. pylori into 2 phenotypes; Type 1, ulcerogenic strain (T1U; cagA*VacA*) and Intermediate, nonulcerogenic strain (INU; cagA*VacA*). Of 71 strains, 57.7% and 42.3% represented T1U and INU, respectively. The prevalence of these two types in PUD were T1U, 63.2%, T2NU 236.8% and in NUD were T1U 51.5%, INU48.5%. The prevalence of T1U was not significantly higher in PUD patients than in NUD patients (p>0.05). The results of the analysis indicated that cagA and VacA are not the predictive markers for PUD in our patiens