Abstract
Infection by the bacterium Helicobacter pylori is a putative cause of various gastric disorders, including gastric adenocarcinoma. Incident rates are associated with variants of the H. pylori virulence factor cytotoxin-associated gene A protein (CagA), encoded by the gene cagA. However, these variants have not been characterized in China, where gastric cancer is common. We investigated the diversity of CagA variants in H. pylori strains isolated from a Chinese population. The 3' variable region of cagA genes from 66 clinical isolates in China were amplified by polymerase chain reaction, sequenced, aligned, and analyzed. All 66 H. pylori strains were CagA-positive, of which 93.9% were East Asian type and the tyrosine phosphorylation motifs (TPMs) were EPIYA-ABD. The remainder was Western type, in which TPMs were EPIYA-ABC. Interestingly, two of sixty-two strains (3.2%) of the East Asian type were mutated into ESIYA-B, whereas all four Western type (100%) strains were mutated into EPIYT-B. Both of the two strains with Western-type CagA obtained from gastric cancer patients contained a distinguished mutation on the first residue following the EPIYA site in the EPIYA-A motif. The predominant CagA type in these H. pylori strains isolated from Chinese patients in China was East Asian, with TPMs EPIYA-ABD, and there existed mutations in both the East Asian and Western type CagA.
Highlights
Helicobacter pylori, a spiral microaerophilic gram-negative bacterium, colonizes the stomachs of 50% or more people worldwide [1]
The predominant cytotoxin-associated gene A protein (CagA) type in these H. pylori strains isolated from Chinese patients in China was East Asian, with tyrosine phosphorylation motifs (TPMs) EPIYA-ABD, and there existed mutations in both the East Asian and Western type CagA
The gene amplification and sequencing protocols were successful, and all the H. pylori strains detected in this study were cagA-positive
Summary
Helicobacter pylori, a spiral microaerophilic gram-negative bacterium, colonizes the stomachs of 50% or more people worldwide [1]. It is the causative agent of many peptic disorders, including gastritis, gastric and duodenal ulcers, and gastric mucosa-associated lymphoid tissue lymphoma. Not all people with H. pylori infections will suffer these diseases—about 30% of the population of Western countries is infected but the rate of gastric cancer is only 0.1% 1%. In East Asian countries such as China, Japan, and Korea, the prevalence of H. pylori infection is 60% 88%, and H. pylori-associated gastric cancers occur more frequently than in Western countries [4,5,6]. Many epidemiological studies have suggested that progression from H. pylori infection to adverse effects is controlled by combinations of genetic variants in the host, environmental factors, and H. pylori gene polymorphisms [7,8,9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
