Prevalence of Helicobacter pylori pathogenicity-associated cagA and vacA genotypes among Pakistani dyspeptic patients
Prevalence of Helicobacter pylori pathogenicity-associated cagA and vacA genotypes among Pakistani dyspeptic patients
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DOI：
10.1111/j.1574-695x.2008.00492.x
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发表时间：
2009-01-01
影响因子：
--
通讯作者：
Khanum, Azra
中科院分区：
文献类型：
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作者：
Ahmad, Tanvir;Sohail, Khawar;Khanum, Azra
细胞毒素相关基因A(CagA)和空泡毒素基因A(VacA)产物被认为是幽门螺杆菌最重要的致病决定因素。幽门螺杆菌是一种革兰氏阴性菌，可引起十二指肠溃疡、胃炎和粘膜相关淋巴组织病等胃肠道疾病。据报道，在巴基斯坦人口的不同地区，幽门螺杆菌的流行率较高；然而，没有与毒力相关的遗传决定因素的数据。这项研究的目的是确定毒力相关基因，cagA，VacA，特别是VacA等位基因变异在巴基斯坦消化不良患者中的流行情况。胃活检标本取自78例有消化不良症状的成人患者。提取DNA，用聚合酶链式反应分析幽门螺杆菌及其基因分型。涉及16S rRNA基因的属特异性聚合酶链式反应显示，78例患者中有66例幽门螺杆菌阳性，在这项特殊研究中，总的患病率为84.6%。VacA基因分型以S1b/m2最常见(54.5%)，其次为S1a/M1(19.7%)。CagA阳性率为24.2%，且与S1a/M1、VacA密切相关。毒力基因CagA和VacA等位基因S1a/M1的流行率低于邻国报道。
The cytotoxin-associated gene A (cagA), and the vacuolating cytotoxin gene A (vacA) products are considered the most important pathogenic determinants of Helicobacter pylori, a gram-negative bacterium causing gastrointestinal disorders such as duodenal ulcers, gastritis and mucosa-associated lymphoid tissue disease. A higher prevalence of H. pylori has been reported in various regions in the Pakistani population; however, no data are available about the virulence-associated genetic determinants. The objective of this study was to determine the prevalence of virulence-associated genes, cagA, vacA and particularly vacA allelic variants among dyspeptic patients from Pakistan. Gastric biopsy samples were obtained from 78 adult patients presenting dyspepsia symptoms. DNA was isolated and analyzed for the presence of H. pylori and its genotypes by PCR. Genus-specific PCR involving 16S rRNA gene revealed that 66 of the 78 patients were positive for H. pylori, an overall prevalence of 84.6% for this particular study. The most common vacA genotype was s1b/m2 (54.5%) followed by s1a/m1 (19.7%). cagA was positive in 24.2% of the cases and strongly associated with s1a/m1, vacA. The prevalence of virulent cagA, and vacA allelic form s1a/m1 was lower than that reported from neighboring countries.