Genetic characterisation of Helicobacter pylori isolates from an Argentinean adult population based on cag pathogenicity island right-end motifs, lspA-glmM polymorphism and iceA and vacA genotypes.

Isolates of Helicobacter pylori from 88 patients were characterised by cagA status, cagA pathogenicity island (PAI) right-end motifs, iceA, vacA and lspA-glmM genotypes, primarily by PCR-based analysis, to investigate whether Argentinean isolates differed from those recovered in southern Europe or other Latin American countries. PCR-based analysis of vacA alleles was confirmed by reverse hybridisation in 56 cases, while sequence analysis was performed either when iceA and vacA genotypes could not be determined by PCR, or to investigate PCR and reverse hybridisation vacA genotyping discordance. Typing by lspA-glmM restriction fragment length polymorphism was performed with HhaI and AluI. The pattern of cag PAI right-end motifs and the prevalence of type Ia were similar to those in isolates from southern European countries, with cagA(+)/iceA1/vacA-s1 m1 being the commonest genotype. Reverse hybridisation identified a vacA-s1a/s1b recombinant allele, confirmed by sequencing analysis. Analysis of lspA-glmM genotypes identified at least 73 unrelated strains. Few mixed infections were identified, but in one case, isolates from a single biopsy exhibiting two vacA alleles were shown by lspA-glmM fingerprints to be two unrelated strains. No associated effect on ulcer disease risk was demonstrated by analysis of cagA, vacA and iceA status. Overall, the isolates of H. pylori from Argentina were similar to isolates from southern Europe or Latin American countries, and infections were associated mainly with single H. pylori strains.

Helicobacter pylori vacA genotypes, cagA status and ureA-B polymorphism in isolates recovered from an Argentine population.

Several reports have evidenced geographic differences in the prevalence of vacA (vacuolating cytotoxin gene) alleles and cagA (cytotoxin-associated gene) status among Helicobacter pylori isolates. We investigated the occurrence of these virulence-associated genes status among our isolates, and their relationship with ulcer disease outcome. Besides, ureA-B polymorphism was studied. One hundred isolates, comprising 32 from patients with ulcer disease (UD) and 68 from patients with non-ulcer dyspepsia (NUD), were analyzed. Eighty-four percent of isolates were cagA-positive without statistically significant difference in prevalence between patients with UD or NUD. Genotype vacA-s1m1 was predominant, although unlike other South American regions, subtype s1am1 occurrence was higher than s1b. The multivariate model used to estimate the predictive value of cagA and vacA status for UD development disclosed infection with vacA-s1am1 isolates as the only variable that increased the risk of UD onset. ureAB fingerprinting showed considerable genetic divergence among isolates, however, confirmed that certain DNA banding profiles are conserved worldwide.