Distinct Diversity of the cag Pathogenicity Island among Helicobacter pylori Strains in Japan

Abstract

The severity of Helicobacter pylori-related disease is correlated with the presence of a cag pathogenicity island (PAI). Genetic diversity within the cag PAI may have a modifying effect on the pathogenic potential of the infecting strain. We analyzed the complete cag PAI sequences of 11 representative Japanese strains according to their vacA genotypes and clinical effects and examined the relationship between the diversity of the cag PAI and clinical features. The cag PAI genes were divided into two major groups, a Western and a Japanese group, by phylogenetic analysis based on the entire cag PAI sequences. The predominant Japanese strains formed a Japanese cluster which was different from the cluster formed by Western strains. The diversity of the cag PAI was associated with the vacA and cagA genotypes. All strains with the s1c vacA genotype were in the Japanese cluster. In addition, all strains with the East Asian-type cagA genotype were also in the Japanese cluster. Patients infected with the Japanese-cluster strain had high-grade gastric mucosal atrophy. These results suggest that a distinct diversity of the cag PAI of H. pylori is present among Japanese strains and that this diversity may be involved in the development of atrophic gastritis and may increase the risk for gastric cancer.

Birth and death of genes linked to chromosomal inversion

“…A region of approximately 1 kb in the cag pathogenicity island that includes cagQ was reported to be inverted in some Japanese strains (15). Our detailed sequence comparison confirmed a similar inversion in Shi470 and in three out of the four Japanese genomes and, furthermore, strongly suggested that these inversion events likely occurred by two steps of DDAI with generation of inverted repeat pairs of 87 bp and 82 bp (Fig.…”

Helicobacter pylori vacA d1 Genotype Predicts Risk of Gastric Adenocarcinoma and Peptic Ulcers in Northwestern Iran

“…In contrast, there is no significant correlation between the vacA genotypes and gastroduodenal disease in East Asian countries. The results of several studies have indicated that some Asian strains are influenced by genetic exchange with neighboring countries and are similar to other isolates from Western countries (Yamaoka et al, 2002;Azuma et al, 2004;Yamazaki et al, 2005;Satomi et al, 2006;Latifi-Navid et al, 2010), Whereas none of the Western strains have an East-Asian-type gene sequence (Xia et al, 2009). Since East Azerbaijan, like Ardabil and Mazanderan could be considered as the high incidence areas of GC in Iran (Somi et al, 2008;Latifi-Navid et al, 2013), H pylori strains from this region also might be similar to other isolates from Western Eurasia and placed in the hpEurope population (Latifi-Navid et al, 2010).…”

EPIYA motif patterns among Cuban Helicobacter pylori CagA positive strains

“…We hypothesize that the absence and relatively low percentage of H. pylori isolates carrying the more carcinogenic D or multiple C EPIYA motifs could be the main factor that influences the low rate of GC in our country. The absence of East-Asian CagA type in our study was an expected result, since this type is almost restricted to East Asian patients (38)(39)(40)(41). EPIYA-D motif represents the CagA genotype with the highest association to premalignant lesions and GC development in infected persons (15,16).…”