插入序列IS605与cag致病岛分割在中国人幽门螺杆菌中的不一致性

Difference of cag pathogenicity island splitand IS60 5 detected in Chinese Helicobacter pylori strains

目的 :探讨中国人群感染的幽门螺杆菌 (Hp)中 IS6 0 5在 cag致病岛基因分割中的地位和作用。 方法 :采用 PCR方法检测 10 7例临床分离培养的 Hp菌株 ,分别扩增 cag A中的 2 98bp片段、cag致病岛中 cag 与 cag 连接处的 2 2 8bp片段及 IS6 0 5中的 116 7bp片段。 结果 :作为 cag致病岛一部分的 cag A ,其阳性的检出率为 92 .5 % ,在慢性胃炎、消化性溃疡、胃癌等疾病间的检出率无显著差异 (P>0 .0 5 )。 cag 与 cag 连接处、即未被分割为 cag 与 cag 的 cag致病岛的检出率仅有4 .7% ,而作为参与分割 cag致病岛的 IS6 0 5 ,其检出率仅有 4 3.9% ,明显低于被分割为 cag 与 cag 的 cag致病岛的检出率 ,IS6 0 5在十二指肠溃疡中的检出率 (13.6 % )明显低于慢性胃炎 (5 2 .2 % )中的检出率 (P<0 .0 5 )。而呈连续状态 cag致病岛在十二指肠溃疡中的检出率 (14 .8% )则显著高于慢性胃炎 (1.5 % )中的检出率 (P<0 .0 1)。 结论 :在中国人群感染的 Hp中 ,IS6 0 5的检出率与 cag 与 cag 呈连续状态的 cag致病岛检出率明显不符 ,提示不仅有 IS6 0 5 ,可能还存在有其他类似转座子的基因成分参与

Objective:To investigate the role of IS6 0 5 in cag pathogenicity island split in Chinese H elicobacter pylori (Hp) strains.Methods:Cag A and conjunction of cag and cag in cag pathogenicity island and IS6 0 5 was amplified by polymerase chain reaction(PCR) in 10 7Hp strains isolated from Chinese patients. Results:The expected 2 98bp am plicom to cag A was identified in 99strains,while 2 2 8bp products to conjunction of cag and cag was in 5 strains,and 116 7bp fragm ent to IS6 0 5 was in 4 7strains. The rate of IS6 0 5 detected did not match that of split cag pathogenicity islands. Detectable rate of IS6 0 5 was lower in duodenal ulcer than in gastritis(P <0 ,0 5 ) ,and detectable rate of contiguous cag pathogenicity island was higher in duodenal ulcer than in gastritis (P<0 .0 1) . Conclusion:The cag pathogenicity island split is not corresponding to detectable IS6 0 5 ,suggesting conjunction between cag and cag can be split by other genetic element besides IS6 0 5 ,cag pathogenicity island split and IS6 0 5 insertion m ay reduce the gradient virulence of Hp. [