Study On The Antimicrobial Agents Resistant Status And Genotypes Of Helicobacter Pylori Isolated From Patients In Lanzhou Area

Objective:1.To investigate the antimicrobial agents resistant status of Helicobacter pylori (Hp) isolated from patients suffered with upper gastrointestinal diseases to five common medicines (amoxicillin, clarithromycin, metronidazole, levofloxacin, furaltadon) and the relationship between the antimicrobial agents resistance and the diseases in Lanzhou area. It will be provided as a guideline for choosing effective agents to eradicate Hp in Lanzhou area.2.To investigate the genotypes of vaculating cytotoxin A (vacA), cytotoxin associating gene protein(cagA), and sialic acid binding adhesion(sabA) of Hp strains isolated from patients in lanzhou area. Analyzing the relationship between the genetic diversity of Hp and high prevalence of upper gastrointestinal diseases in the area. To supply the research work about sabA of Hp in China. The results will provide a theoretical support to explore the reasons of high prevalence of upper gastrointestinal diseases and vaccine research work.Methods:1.The gastric mucosa tissues of 197 patients with upper gastrointestinal diseases were sampled to diagnose the pathological type. Microaerophilic cultivation, Gram stain, Urease test, and Oxidase test were used to isolate and identify Hp from the samples. Kirby-Bauer test was performed to test the resistance of isolated Hp strains to amoxicillin, clarithromycin, metronidazole, furaltadon, levofloxacin. Analyzing the resistant status of Hp to the five antimicrobial agents among the groups of sex, age, and pathological type respectively.2.DNA of 80 Hp strains was extracted. The primers of sla,slb,slc,ml,m2 of vacA, cagA, and sabA were designed. The genotypes of vac A, cagA and sab A of Hp of Lanzhou area were detected by the technique of polymerase chain reaction (PCR). Analyzing the virulent genes among different diseases and relationship between the types of vacA of Hp and the upper gastrointestinal diseases.Results:1.Totall 81 strains of Hp were isolated from 197 samples(41.12%) and there was no difference in the positive rate between the patients with sex and age(P>0.05). The positive rate of Hp infection in patients with peptic ulcer was significantly higher than that of patients with gastritis(P<0.05).The resistant rate of Hp to amoxicillin, clarithromycin, metronidazole, furaltadon and levofloxacin was 3.70%,7.41%,67.90%, 3.70% and 6.17%, respectively and with no difference between patients with different sex, age and the pathological type.2.vac A of 80 Hp strains were all positive. The highest positive type was s1a+s1c (78.8%), following with s1a (11.3%) and s1c(7.5%). The s1b of Hp was the lowest. In the middle region(m) alleles of vacA, m2 was dominant (82.5%) and ml strains accounted for only 2.5%. There still existed 12 strains that the m alleles can not be detected. The positive rate of cagA was 95.0%(76/80), and sabA was 66.3%(53/80). There were no significant difference between vacA, cagA positive Hp and the different upper gastrointestinal diseases (P>0.05), but the positive rate of sabA in patients with peptic ulcer was significantly higher than that of patients with gastritis (P<0.05). There was no significant difference among different genotype of vacA in the upper gastrointestinal diseases.Conclusion:1.The isolated positive rate of Hp among the patients of peptic ulcer is signficant higher than that in gastritis. This indicates that the Hp infection may play important roles in the occurring of peptic ulcer in the area.2.Metronidazole should not be used as first-line agent for Hp treatment in Lanzhou area due to its higher resistance rate. Furaltadone and amoxicillin should be used first for Hp eradication therapy. The multiple resistances Hp are emerging in the area.3.Hp isolates are mainly type I possessing cagA and vac A in Lanzhou area. This type Hp are severely in pathogenicity. And this maybe related with high prevalence of upper gastrointestinal diseases in the area.4.The positive rate of s1a and s1c of Hp in Lanzhou area is higher than the other reported place. This maybe linked with the gene mutation or the mixed infection. It is worthy to explore the relationship between the high positive rate of s1a and s1c of Hp in Lanzhou area and the high occurring of upper gastrointestinal diseases in the area.5.There exists sab A among the Hp in Lanzhou area and it's positive rate is significantly higher in the patients with peptic ulcer than that in gastritis. The roles of sabA of Hp in the occurring of upper gastrointestinal diseases should make far detection.