| Aim: To evaluate the prevalence of H.pylori resistance to metronidazole among three People in Yunnan, compare rdxA gene identity of H.pylori strains among three people in China with that in west countries and research metronidazole resistance gene mechanism of H.pylori strains in China. Method: (1) Isolated and cultured H.pylori strains from gastric biopsy specimens, from patients diagnosed H.pylori related chronic gastritis and peptic ulcer by gastroscopy, rapid urease test and histology. (2) H.pylori strains susceptibilities to metronidazole were tested by the use of the Epsilometer test (E-test). (3) Amplified VacA (vacuolating cytotoxin gene A), cagA (cytotoxin-associated gene A), iceA (induced by contact with epithelium gene A), babA2(blood group antigen binding adhesin)gene of H.pylori strains by polymerase chain reaction (PCR) to determine H.pylori gene subtypes and gene types and distinguish strains of multiple and non-multiple infection. (4) The non-multiple, sensitive H.pylori strains, wereselected and subjected to metronidazole induction experiment, which made H.pylori strains transform susceptibility to resistance. (5) Extracted DNA of metronidazole sensitive and resistant pairs of H.pylori strains before and after induced, amplified by PCR and sequenced rdxA gene to compare rdxA gene identity of H.pylori strains among three people in China with that in west countries and analyse difference between rdxA gene sequences of sensitive H.pylori strains before induced and those of resistant H.pylori strains after induced.Result: (1) In 109 H.pylori strains, metronidazole resistant rate was 67.89%. In 33 H.pylori strains of Han people, resistant rate was 63.63%. In 31 H.pylori strains of Bai people, resistant rate was 74.19%. In 45 H.pylori strains of Naxi people, resistant rate was 66.66%. There was no significant difference in the metronidazole resistant rate of H.pylori among Han, Bai, Naxi people group. (2) There was no relation between metronidazole resistant rate of H.pylori from Han, Bai, Naxi people and three people and age, upper gastroduodenal diseases, VacA gene subtypes, cagA, iceA, babA2 gene types and H.pylori colonization density. In the facet of gender, metronidazole resistant rate of H.pylori from male group of Han people was significantly lower than that from female group ( x2=5.304, P=0.027). But there was no relation between metronidazole resistant rate of H.pylori from Bai, Naxi people and gender. (3) 4 of 12 H.pylori strains were induced successfully with metronidazole, including 2 strains of Han people (strain number: 1-12, 1-170) , 1 strain of Bai people (strain number: 3-108) , 1 strain of Naxi people (strain number: 4-123). (4) Compared with that of standard H.pylori 26695, DNA sequence of rdxA gene from strain of Han people, Bai people, Naxi people had 95.2%, 95.1%, 94.8% identity. Identitywas 97.6% compared rdxA gene sequence from strain of Han people with that of Bai people. Identity was 97.8% compared rdxA gene sequence from strain of Han people with that of Naxi people. Identity was 97.3% compared rdxA gene sequence from strain of Bai people with that of Naxi people. (5) H.pylori strain 1-170R from Han people, strain 3-108R from Bai people, H.pylori strain 4-123R from Naxi people contained mutations within their rdxA genes.Conclusion: (1) The metronidazole primary resistance rate of H.pylori in Yunnan was 67.89%. There was no significant difference in the metronidazole resistant rate of H.pylori among Han, Bai, Naxi people group. At present, there is no research about antibiotic resistance investigation of H.pylori in Yunnan. (2) There was no relation between metronidazole resistant rate of H.pylori strains from Han, Bai, Naxi people and three people and age, upper gastroduodenal tract diseases, VacA gene subtypes, cagA, iceA, babA2 gene types and H.pylori colonization density. In the facet of gender, metronidazole resistant rate of H.pylori from male group of Han people was significantly lower than that from female group. But there was no relation betw... |
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