Article ID: JJID.2014.165
Infection with different strains of H. pylori and emergence of new genomic variants during their long term gastric colonization are assumed as main reasons for eradication failure. This project was designed to detect relatedness and genetic variations among the H. pylori single isolates from each patient in Iran. Genotyping and arbitrarily primed PCR fingerprinting (RAPD) were used in this regard. Multiplex-PCR amplification of gene alleles encoding virulence factors vacA (m/s), cagA, iceA (A1/A2) and comparison of RAPD patterns of different singles colonies were performed for each individual patient. The results showed high frequency of diversity among the H. pylori strains. Nearly, 23% of the infected patients showed single type infection. The infection types related, unrelated, and related/unrelated were found among 25.6%, 12.8%, and 38.5% of the patients, respectively. Both mixed type infection (77%) and quasispecies development (15.4%) were detected among these patients. Genotype conversion among vacA (41.6%), cagA (41.6%), and iceA (50%) alleles was observed for those strains with identical or related RAPD patterns. Coevolution of different alleles was also detected in a patient infected with strains presenting same RAPD patterns. Collectively, results of this study revealed occurrence of quasispecies development, mixed type infection and changes of virulence properties of H. pylori strains among the studied patients.
