幽门螺杆菌VacA基因型与耐药性分析

VacA genotypes of Helicobacter pylori and its drug resistance

目的探讨幽门螺杆菌(H.pylori)VacA基因型在各种胃肠疾病中的分布及其对常用抗生素的敏感性。方法从胃十二指肠疾病患者胃黏膜标本中分离培养H.pylori,用PCR测定VacA基因型,并采用琼脂稀释法进行对阿莫西林、克拉霉素、甲硝唑3种抗生素的药物敏感性试验。结果 108株H.pylori菌株,VacAs1a阳性85株(78.7%),VacA s1b阳性22株(20.4%),VacA m1阳性29株(26.9%),VacA m2阳性77株(71.3%),VacAs1a/m2阳性66株(61.1%),未发现s2型菌株。其中,慢性胃炎患者VacAs1a阳性率为65.4%(34/52),消化性溃疡患者VacAs1a阳性率为90.0%(36/40),胃癌患者VacAs1a阳性率为93.8%(15/16)。对阿莫西林、克拉霉素、甲硝唑的耐药率分别为18.5%、5.6%、65.7%,对阿莫西林耐药的20株菌株中,19株为VacAs1a型。结论 H.pylori菌株VacA基因型绝大多数为s1a/m2型,该型菌株存在于各种胃肠疾病中。本地区幽门螺杆菌对克拉霉素的耐药率较低,对甲硝唑的耐药率较高,而对阿莫西林耐药的菌株多数为VacAs1a型。

Objective To investigate the distribution of Helicobacter pylori （H. pylori） VacA genotypes in different gastrointes- tinal diseases and its resistance to common drugs. Methods VacA genotypes of 108 H. pylori strains isolated from patients with chronic gastritis, peptic ulcer and gastric cancer were tested by polymerase chain reaction （PCR）, the susceptibility test of H. pylori to amoxicillin,clarithromycin,metronidazole were performed by means of the agar dilution method of assay. Results The frequen- cies of the signal allele sla,slb and the middle-region allele ml ,m2 were 85（78.7%） ,22（20.4%0） ,29（26.9%） ,77（71.3%）respec- tively. The numbers of H. pylori strains of VacA s la/m2 positive were 66 （61.1%）. The s2 form was not found. The positive rates of VacA sla of H. pylori strains isolated from patients with chronic gastritis,peptic ulcer and gastric cancer were 65.4% （34/52）, 90. 0% （36/40） and 93.8%（15/16） respectively. Resistance rates of H. pylori strains were as follows, 18.5% to amoxicillin, 5. 6% to clarithromyein and 65. 7% to metronidazole. Nineteen out of 20 H. pylori strains resistant to amoxicillin were VacA sla form. Conclusion The majority of H. pylori strains isolated from Chongqing patients express sla/m2. The sla/m2 genotype is dis- persed in all of the gastrointestinal diseases associated with H. pylori. For the isolated H. pylori strains in Chongqing area, the drug resistance to clarithromycin is lower, to metronidazole is higher. The most of H. pylori strains resistant to amoxicillin were Va- cA sla form.