浙江地区小儿幽门螺杆菌cagA基因变异性研究

Study on cagA gene in children with Helicobacter pylori(Hp) infection in Zhejiang Province

目的 研究浙江地区儿童感染的幽门螺杆菌 (Hp)cagA基因的变异性。方法 应用3对不同引物对66例Hp感染患儿胃粘膜Hp菌株通过聚合酶链反应 (PCR)技术 ,分别扩增cagA基因不同DNA片段 ,检测cagA基因阳性 (cagA +)检出率 ;用免疫印迹法检测患儿血清CagA抗体。结果 Hp 菌株cagA基因DNA404bp、349bp、298bp 片段分别经3对引物扩增后 ,cagA +检出率分别为56.1%、39.4%、72.7% ,三者之间差别有显著性意义(χ2=14.63,P<0.01) ,总阳性检出率为90.9%。66例患儿血清CagA抗体阳性率为97.0%。结论 浙江地区儿童感染的Hp菌株cagA基因存在变异性和多态性 ,增加引物对数量进行检测可以提高Hp菌株cagA +检出率。

Objective To study the variability of cagA gene in children with Hp infection in Zhejiang Province.Methods Three pairs of primers were selected,different DNA fragments of cagA from66gastric biopsy specimens were amplified by PCR.Serum cagA antibody from children with Hp infection was examined by western blot analysis.Results With three pairs of primers it was revealed that the positive rates of cagA DNA fragments of404bp,349bp and298bp were56.1%(37/66),39.4%(26/66)and72.7%(48/66)respectively(χ 2 =14.63,P<0.01).The general positive rate of PCR in biopsy specimens was90.9%(60/66);whereas the positive rate of serum CagA antibody was97.0%(64/66).Conclusion Most Hp strains in children with Hp infection carry cagA gene and express CagA proteins.The positive rates of cagA gene examined by PCR with different primers,which suggests there exists the variability of cagA gene in children with Hp infection.