Genotyping cagA, vacA subtype, iceA1, and babA of Helicobacter pylori isolates from Korean patients, and their association with gastroduodenal diseases

The genetic status of cagA, vacA subtype, iceA1, and babA, and the relationship to gastroduodenal diseases were assessed in Helicobacter pylori isolates in Korea. Seventy-six strains of H. pylori were isolated from the antrum and the corpus of 41 adult patients (22 with peptic ulcer and 19 with gastritis). The cagA, iceA1, and babA genes were assessed by polymerase chain reaction and the vacA subtypes were determined by reverse hybridization-line probe assay. The positive rates of 349-bp cagA, 208-bp cagA, iceA1, and babA genes were 97.4%, 96.1%, 84.2%, and 36.1%, respectively. The vacA s1a, s1b, s1c, and s2 variants were detected in 11.8%, 3.9%, 80.4%, and 1.3%, respectively. m1 (78.9%) is more prevalent than m2 (5.3%). The most common vacA genotype was s1c/m1 (61.9%), and 14 isolates (18.4%) contained mixed vacA genotypes from a single biopsy specimen. Twenty-one (60%) of 35 patients were infected with more than two strains of different cagA, iceA1, babA, and vacA genotypes. None of cagA, iceA1, babA, and vacA s1/m1 were associated with peptic ulcer. In conclusion, most H. pylori isolates in Korea carry cagA, iceA1, and vacA s1c/m1 genes, and reside with multiple strains. These genes do not correlate with the peptic ulcer in the Korean patients.

Genotypic variation of Helicobacter pylori isolated from gastric antrum and body in Korean patients

Although most persons infected with Helicobacter pylori harbor a single strain of the organism, multiple strain colonization in the same patient is also occasionally reported in developed countries. The aims of this study were to determine the prevalence of multiple strain colonization in Korean patients and to detect the cagA, iceA1, and babA status of H. pylori isolated from the antrum and body of the stomach. H. pylori was obtained from 35 patients from the antrum and body of the stomach. The genomic diversity of H. pylori was determined by random amplified polymorphic DNA analysis. The status of cagA, iceA1, and babA genes of H. pylori was assessed by polymerase chain reaction with appropriate primers. Clearly different diversity patterns were identified among the isolates from 35 individual patients. Eighteen (51.4%) patients had a single strain of H. pylori. Eight (22.9%) and nine (25.7%) patients had subtypically (one or two bands difference) and typically (clearly different pattern) different strains of H. pylori in the antrum and body, respectively. Among the 70 isolates of H. pylori from 35 patients, the positive rates of 349-bp and 208-bp cagA gene fragments and the iceA1 gene were 68/70 (97.1%), 68/70 (97.1%), and 58/70 (82.9%), respectively. However, the babA gene was found in 22/66 cases (31.4%). In five out of 18 patients with a single strain, the genetic status of cagA, iceA1, and babA varied between the isolates from the antrum and the body. In 8/17 patients with subtypically or typically different strains, the gene status differed between antrum and body isolates. The prevalence of co-colonization with typically or subtypically different strains is high in Korea, and sub-clones with different pathogenic gene status exist within strains of identical RAPD patterns.