[Dissemination of insertion sequences IS605, IS606 among clinical isolates of Helicobacter pylori in China].

Objective To study the distribution of IS605, IS606 among clinical isolates of Helicobacter pylori in China. Methods A total of 104 H.pylori strains isolated from 5 different geographic regions in China were analyzed by PCR and dot blot. Results Forty two strains out of the 104 isolates from 5 regions in China were found containing IS605 with 19 containing IS606. The frequency (66%) of IS605 positive strains from Yunnan province was higher than that from other areas. The different distribution of IS606 was neither associated with geographical regions nor with the presence of IS605 but IS606 were associated with the different clinical outcomes. However,the two reading frames ORFA and ORFB of IS605 were constantly coexisting. Conclusion In China, IS605 and IS606 of H. pylori were widely exisiting but the present of IS605 in H. pylori might be associated with geographic origin.