河西走廊地域幽门螺杆菌vacA和cagA基因型分布研究

Study on the vacA and cagA genotypes of Helicobacter pylori Hexi corridor

[目的]探讨河西走廊胃癌高发区胃癌患者幽门螺杆菌(Helicobacter pylori,Hp)vacA和cagA基因型的分布情况,为当地Hp流行病学研究和疫苗研制提供参考。[方法]复苏和纯培养从河西走廊地域医院收集并分离到的89株Hp,抽提DNA,设计vacA信号序列s1a、s1b、s1c和cagA引物,PCR扩增vacA信号序列以及cagA基因并鉴定,分析Hp菌株中vacA和cagA基因型分布以及不同基因型与患者临床病理类型的关系。[结果]89 Hp菌株vacA基因均阳性,其中信号序列为s1a型者占66.29%,s1c型占33.71%,未见s1b型。vacA s1a基因型在慢性胃炎、消化性溃疡、胃癌各组中的构成比均高于s1c基因型。不同病理类型的疾病间,vacA s1a和s1c基因型构成均差异无统计学意义(P>0.05)。cagA阳性率为97.75%,cagA+菌株在慢性胃炎、消化性溃疡、胃癌各组中的构成比均高于cagA-菌株。不同病理类型的疾病间,cagA+和cagA-菌株构成均差异无统计学意义(P>0.05)。[结论]河西走廊地域Hp菌株大多数为致病性高的Ⅰ型菌株;vacA信号序列以s1a为主,其次为s1c;cagA+的高毒力菌株分布广泛,这可能是当地上消化道疾病高发的重要原因。

[Objective]To explore the genotype distribution of vacA and cagA of Helicobacter pylori（Hp）Hexi Corridor,aplace with high incidence of gastric cancer.[Methods]Eighty-- nine stocked Hp which isolated from the regional hospitals in Hexi Corridor were recovered and cultured.HpDNA was extracted by Phenol-- chloroform method.The primers of vacA signal sequence s1 a,s1b,s1 cand cagA were designed.PCR technique was used to amplify and identify vacA s sequence s1 a,s1b,s1 cand cagA genotype.The distribution of vacA s sequence and cagA genotype among the detected Hpand the relationship between HpvacA s sequence and cagA genotype and patient＇s clinicopathological types were analyzed by statistics.[Results]Hp vacAgene in the detected 89 strains were all positive and the s sequence genotype included s1a（66.29%）and s1c（33.71%）.There was no s1 bgenotype verified.HpvacA s1 agenotypes constituent ratio in patients with chronic gastritis,peptic ulcer,gastric cancer group were higher than s1 cgenotypes respectively.Between different types of disease pathology,either vacA s1 agenotypes or s1 cgenotypes all showed no significant difference（P〉0.05）.CagA was detected in 97.75% of the strains investiga-- ted.HpcagA^＋ strains constituent ratio in patients with chronic gastritis,peptic ulcer,gastric cancer group were higher than cagA^- strains respectively.Between different types of disease pathology,either cagA^＋ strains or cagA^- strains all showed no significant difference（P〉0.05）.[Conclusion]The most popular Hp strains in Hexi corridor are highly pathogenicⅠtype strains.The main vacA s sequence is s1 agenotype and follows by the s1 c.The highly virulent cagA^＋ strains are widely distributed,which may be an important reason for the high incidence of gastrointestinal disease in local.