幽门螺杆菌对抗生素的敏感性及细胞毒素相关蛋白A基因检测

Detection of Antibiotic Susceptibility and Cytotoxin Associated Protein A Gene in Helicobacter Pylori

目的 :检测 15 3株幽门螺杆菌对甲硝唑、四环素、阿莫西林的敏感性、β 内酰胺酶和细胞毒素相关蛋白A(CagA)基因。方法 :琼脂稀释法检测药物最低抑菌浓度、纸片酸度定量法检测 β 内酰胺酶及PCR法检测CagA基因。结果 :甲硝唑耐药菌株为 72 .5 % ,四环素耐药菌株为 5 8.9% ,阿莫西林耐药菌株为 41.2 %。三重耐药菌株达 31%。来自女性的甲硝唑耐药菌株比来自男性的多见 (P <0 .0 5 )。所有菌侏 β 内酰胺酶均阴性。含CagA基因的菌株为6 6 .7% ,并发现甲硝唑敏感菌株含CagA基因比耐药菌株更常见 (P <0 .0 5 )。结论 :本地区HP耐药菌株多见 ,且出现大量多重耐药菌株。阿莫西林耐药机制与 β 内酰胺酶产生无关。耐药性与毒力基因存在一定相关性。

s Purpose: To investigate the helicobacter pylori(HP) antibiotic resistance to metronidazole, tetracycline, amoxycillin; β lactamase and Cytotoxin Associated Protein A(Cag A) gene. Methods: 153 helicobacter pylori clinic isolates collected from the number nine People`s hospital affiliated to Shanghai second medical university during the period from January 1998 to February 1999 were examined. Minimum inhibitory concentration(MC) was detected by agar dilution method, β lactamase by means of acidometry using β lactamase detection paper and cag A gene by PCR. Results: 72.5% of strains was resistant to metronidazole, 58.9% was resistant to tetracycline and 41.2% was resistant to amoxycillin. Multiresistant strains which resist to the three antibiotics in the meantime were prevalent (31%). Metronidazole resistance were more common in female than in male(P<0.005). β lactamase of all strains was negative. 66.7 % of isolates had Cag A gene. Surprisingly, metronidazole susceptible strains with Cag A gene were more frequent than resistant strains (P<0.05). Conclusion: This study shows not only the distribution of antibiotic resistance and Cag A gene, but also a certain relationship between them. The mechanism of amoxycillin resistance is not linked to the production of β lactamase. This study may be helpful in the epidemiological survey as well as control of helicobacter pylori infections in this area.