淮南地区学生幽门螺杆菌vacA和cagA基因分布特征

目的研究淮南地区学生幽门螺杆菌(Helicobacter pylori,H.pylori)cagA和vacA基因分布特征,为防治工作提供理论依据。方法对74例有消化道症状,年龄在7~24岁的在校学生进行胃镜检查,并在胃窦部取活检粘膜作H.pylori的分离培养,利用聚合酶链反应技术(PCR)测定分离培养出的H.pylori菌株的cagA和vacA基因并进行分型。结果74例学生中,分离培养出H.pylori菌株24例,基因测定结果显示,24株H.pylori临床分离株中,94.7%(23/24)含vacA基因,70.8%(17/24)含cagA基因;其中慢性胃炎vacA和cagA基因检出率分别为94.7%(18/19),70.6%(12/17);2例胃溃疡及3例十二指肠球部溃疡均全部为vacA和cagA阳性;进一步分型发现89.5%(17/19)的慢性胃炎为vacA 和cagA ,而5例溃疡患者均为vacA 和cagA 。结论淮南地区学生H.pylori感染多为vacA 和cagA 菌株,应充分重视H.pylori毒力因子的监测。     

浙江人群幽门螺杆菌cagA/vacA优势基因型和不同基因型混合感染的调查

目的　了解消化性溃疡和慢性胃炎患者感染的幽门螺杆菌 (Hp)cagA vacA优势基因型及不同基因型Hp感染、混合感染与疾病的关系。 方法　选择胃窦、胃体双份活检标本均培养出Hp的 42例慢性胃炎 (CG)和 3 6例消化性溃疡 (PU )患者作为研究对象 ,采用聚合酶链反应 (PCR)检测156份Hp分离株的cagA基因、vacA基因的信号区 (s)和中间区 (m )亚型 ,分析Hp基因型及多株Hp混合感染在CG和PU中的分布。结果　胃窦标本cagA基因的检测中 78例患者中有 75例 (96.2 % )为cagA阳性 ,相应的胃体标本中 ,76例患者 (97.4% )为cagA阳性 ,有 1例 (1.3 % )患者胃窦、胃体检出cagA状态不一的Hp混合菌株。在胃窦标本的vacA基因分型中 ,s1a m1、s1a m2、s1a m1b、s1a m1b m2 4种vacA基因型在 78例患者中所占比例分别为 6.4% (5 78)、55.1% (43 78)、2 6.9% (2 1 78)和 1.3 % (1 78) ,多株混合感染为 3 .8% (3 78) ;而相应的胃体标本中 ,前述四种vacA基因型所占比例依次为 6.4% (5 78)、53 .8% (42 78)、2 5.6% (2 0 78)和 3 .8% (3 78) ,多株混合感染为 5.1% (4 78)。cagA+ s1a m2和cagA+ s1a m1b在胃窦标本中占 51.3 % (40 78)和 2 6.9% (2 1 78) ,而在相应的胃体标本中占 52 .6% (41 78)和 2 5.6% (2 0 78)。少量胃窦、胃体     

Determination of cagA, vacA genotypes of Helicobacter pylori with real-time PCR-method

Presence of cagA gene of Helicobacter pylori (H. pylori) increases proliferation of stomach mucosa and it is an index of raised virulence of the bacteria. The vacA gene of H. pylori induces a serious inflammation of stomach. The purpose of this study was to determine cagA and vacA genotypes of H. pylori using real-time polymerase chain reaction (PCR) method with the double strain DNA-(dsDNA) binding SYBR Green I. dye. Results were compared with those of two immunohistochemical methods. 43 patients' paraffin embedded biopsy tissue samples were examined by histology, epidermal growth factor receptor (EGFR), proliferating cell nuclear antigen (PCNA) immunohistochemistry and melting curve analysis of real-time PCR using LightCycler instrument. Results of histology and real-time PCR from gastric biopsies correlated in 57% of cag acases and in 58% of vac cases. Significant difference was detected between normal and gastritis cases in the presence of cagA gene (p = 0.003) and between normal epithelial and intestinal metaplasia cases in the presence of vacA gene (p = 0.045) by investigation of association of histology and genotype of bacterium. Statistically significant difference (p = 0.02) was found between increased cell proliferation and the presence of gastritis. Significant correlation was found between the presence of cagA gene and EGFR expression in intestinal metaplasia cases (p = 0.0418). Results underlie the statistics that infection with cagA positive H. pylori strain increases the cell proliferation on the stomach mucosa and raises the chance of development of intestinal metaplasia. Infection with vacA positive H. pylori inhibits the signal-transduction pathway of EGFR, which influences mechanisms of mucosa repair. The role of EGFR and H. pylori infection is yet unclear in intestinal metaplasia and cancer. The authors' method seem to be suitable for determination of genotypes of H. pylori.     

不同类型慢性胃炎患者幽门螺杆菌的分离培养、耐药与毒力基因研究

目的 研究不同类型慢性胃炎患者幽门螺杆菌（Helicobacter pylori,Hp）的感染情况,检测分离株的耐药性与毒力基因。方法 采集患者胃黏膜,分离Hp并进行药敏试验。PCR扩增克拉霉素、左氧氟沙星耐药相关基因23S rRNA、gyrA及毒力基因cagA、vacA、iceA,测序并分析23S rRNA和gyrA扩增产物的突变位点。分析慢性胃炎类型与Hp的分离率、耐药性和毒力基因的关系。结果 120例患者共分离获得45株Hp（37.5%）。Hp对甲硝唑、克拉霉素、左氧氟沙星、阿莫西林、呋喃唑酮和四环素的耐药率分别为97.8%、28.9%、28.9%、4.4%、0和0。在克拉霉素和左氧氟沙星耐药菌株中,23S rRNA、gyrA基因最常见的突变位点分别为A2143G（76.9%）和N87K（38.5%）。cagA、vacA s1a、vacA s1b、vacA s1c、vacA s2、vacA m1、vacA m2、iceA1、iceA2阳性率分别为97.8%、97.8%、0、95.6%、0、37.7%、62.2%、71.1%、24.4%。在不同类型慢性胃炎组间,Hp的分离率差异有统计学意义（χ2 = 13.299,P＜0.05）,分离株的耐药率差异均无统计学意义（均P＞0.05）,iceA1、iceA2的分布差异有统计学意义（均P＜0.05）。结论 不同类型慢性胃炎患者Hp的分离率不同,Hp感染治疗可选呋喃唑酮和四环素,iceA1和iceA2毒力基因可能与胃炎类型有关。     

幽门螺杆菌的毒力基因、vacA基因亚型与上消化道疾病关系的研究

目的研究镇海地区幽门螺杆菌(Hp)尿素酶基因(ureA)、细胞毒素相关基因(cagA)、空泡细胞毒素基因(vacA)及vacA基因亚型与上消化道疾病之间的关系。方法用普通聚合酶链反应(PCR)技术,测定84株从上消化道疾病患者胃窦黏膜中分离获得的Hp的ureA基因、cagA基因、vacA基因、vacA基因亚型。结果84株Hp中,ureA、cagA、vacA基因的阳性率分别为100.00%、90.48%、95.24%,cagA、vacA在胃炎、消化性溃疡的阳性率高于胃癌(P<0.05);vacAm2基因的阳性率为79.76%,明显高于vacAm1a(20.24%)、vacAm1b(8.33%)及vacAm1bm2(4.76%),vacAm2在胃炎、消化性溃疡的阳性率高于胃癌(P<0.05),其余3个基因亚型阳性率差异均无统计学意义(均P>0.05)。结论镇海地区Hp相关性上消化道疾病患者感染Hp以ureA阳性、cagA阳性、vacAm2亚型占优势,且均在消化性溃疡及胃炎中的检出率更高。     

中国香港地区幽门螺杆菌毒力基因型与十二指肠溃疡关系的研究

目的：研究幽门螺杆菌（Hp）的重要毒力因子vacA，cagA，iceA及插入序列IS在中国香港地区分离菌株中的分布特征及其与十二指肠溃疡的关系。方法：采用聚合酶链反应（PCR）和Southern blot方法，对72例证实为Hp感染的胃十二指肠疾病患者的胃黏膜标本直接进行检测。结果：72例患者中，69例（95.8％）感染的Hp菌株为vacA sIc型，3例（4.2％）为sIa型；23例（31.9％）为vacAm1b型，46例（63.9％）为vacAm2型；6例（8.3％）为混合型。63.9％（46/72）的患者感染菌株为iceA1型，29.2％（21/72）为iceA2型。CagA的阳性率为88.9％（64/72）。结论：Hp毒力因子vacA，cagA和iceA在香港菌株中的分布有自己的特点；未发现特定cagA，vacA和iceA基因型别与DU相关。     

PCR assay targeting virulence genes of Helicobacter pylori isolated from drinking water and clinical samples in Lahore metropolitan, Pakistan

Helicobacter pylorus is considered for chronic gastritis, gastric ulcers and adenocarcinoma and its high infection rate is observed in overcrowded and lower socioeconomic groups in developing countries. This study was designed to identify the role of drinking water in the transmission and prevalence of H. pylori (HP). Selective HP medium was developed for enrichment and presumptive identification of H. pylori by urease, catalase and species specific 16S rRNA tests. The virulence genes (vacA ‘s’ and ‘m’ regions and cagA) of H. pylori in 90 out of 225 H. pylori positive drinking water samples were present (40%). Ten out of 18 biopsies (55.55%) and 15 out of 50 vomiting fluids of gastric disease patients (30%) were also positive for virulence genes. Anti-H. pylori antibodies were also detected in 31 out of 50 patients’ sera. The presence of virulence genes was also directly confirmed by hybridization studies using non-radioactive DNA probes of 16S rRNA, vacA and cagA genes. The presence of H. pylori in water is due to poor sanitary conditions, improper waste disposal and lack of public health education. PCR-based analysis and colony hybridization can be used for detection of H. pylori in clinical and environmental samples.     

Molecular epidemiology of Helicobacter pylori: separation of H. pylori from East Asian and non-Asian countries

The predominant H. pylori strain circulating among geographic locations differs with regard to the genomic structure. This study determined whether structural subtypes of the cagA 3' repeat region could be used to identify the population of origin of H. pylori isolates. We examined 600 cagA-positive H. pylori (Colombia, 100; USA, 100; France, 100; Canada, 20; Italy, 20; Korea, 100; Japan, 100; Hong Kong, 20; Taiwan, 20; Vietnam, 20). The cagA 3' region was amplified by PCR using primers specific to Japanese and Western 3' cagA gene sequences. PCR using Japanese cagA primers resulted in PCR products in 99-6 % of strains from East Asia but no non-Asian strains. Conversely, PCR using Western cagA primers resulted in amplicons in 100% of non-Asian strains, and only one from East Asia. cagA genotyping is useful for molecular epidemiological studies as strains can be completely separated by differences in the cagA 3' region.     

Surveillance and clinical relevance of vacA genotypes of Helicobacter pylori infecting dyspeptic patients in mid-Essex

The Helicobacter pylori vacuolating cytotoxin is a putative pathogenicity factor encoded by vacA, a mosaic gene with a global distribution. The vacA type prevalence and diversity of H. pylori isolated from antral gastric biopsies of 360 dyspeptic patients in mid-Essex, and of 79 patients from other locations, were investigated in order to test for links with disease severity. Mid (m)-region genotyping and subtyping by vacA HaeIII RFLP (restriction fragment length polymorphism) analysis showed that the m1 and m2 alleles were diverse, with 191 different subtypes. Variation in 44% of strains was accounted for by ten subtypes of which subtype v-1 represented a conserved core (33%) of the m1 form. Prevalence rates for combined mid and signal (s)-region genotypes were 40% for s1/m1, 46% for s1/m2, and 11% for s2/m2. Overall, vacA genotyping provided high typability and discrimination, but no specific RFLP markers could reliably predict a clinically significant presentation due to an H. pylori infection.     

Salt intake and type of intestinal metaplasia in Helicobacter pylori-infected Portuguese men

The relation between salt intake and intestinal metaplasia (IM) types and the potential interaction with H. pylori virulence are poorly understood and may contribute to further understand gastric carcinogenesis. We quantified the association between dietary salt exposure and complete, incomplete, and mixed IM, taking into account the potential effect modification according to the virulence of H. pylori infecting strains. H. pylori-infected male volunteers (n = 233) underwent an upper digestive endoscopy and completed questionnaires comprising different measures of salt exposure (main food items/groups contributing to dietary salt intake, estimated dietary sodium intake, visual analogical scale for salt intake, preference for salty/salted foods). A histological diagnosis was assigned based on the most severe lesion observed. H. pylori virulence was assessed by characterizing vacA and cagA genes. Odds ratios were estimated through age- and education-adjusted logistic regression models. The risk of IM was not significantly increased in H. pylori infected subjects with higher levels of salt consumption. The lack of association was consistent across measures of salt exposure, categories of H. pylori virulence, and types of IM. In conclusion, in this H. pylori positive population, salt intake did not increase the risk of any IM type, regardless of the virulence of the infecting strains.     

幽门螺杆菌中国分离株vacA基因多态性分析

目的 分析幽门螺杆菌(HP)中国菌株vacA基因多态性.方法 对分离自中国7个不同地区、不同胃十二指肠相关疾病患者的119株HP,采用特异引物聚合酶链反应(PER)方法,对其vacA基因进行PCR扩增.根据核酸电泳中产物片段大小确定vacA等位基因类型并统计分析各型分布.对vacA基因核心片段进行PCR扩增和DNA测序,利用软件MEGA4.0对DNA测序结果进行聚类分析.结果 119株HP的vacA基因以sla、m2和il型为主,分别为97.5%(116/119)、68.9%(82/119)和91.6%(109/119).26.1%(31/119)为mlb;slb,mla未检出.vacA组合基因型以sla/m2/il为主(62.2%,74/119),sla/mlb/il次之(25.2%,30/119).不同地区、不同疾病来源菌株sla分布的差异无统计学意义(P>005).而m区基因多态性在疾病类型及分离地区间差异有统计学意义(P<0.01).不同疾病来源菌株间i区基因分型分布的差异无统计学意义,但不同分离地区菌株间差异有统计学意义(P<0.01).119株的vacA基因序列聚类为三个不同组群.结论 HP中国分离株vacA基因型以sla/m2/il组合型为主,sla分型结果与菌株分离地区及疾病类型无关.不同地区、不同疾病来源菌株m区基因分型不同.不同地区菌株vacA基因i区分型不同,但i区基因分型与菌株的疾病来源无显著相关性.

Abstract：

Objective To understand the polymorphism of Helicobacter pylori (H. pylori) vacA alleles in China. Methods A total of 119 H. pylori strains were isolated from different gastroduodenal diseases in 7 different geographic regions in China. vacA and its alleles were identified according to the length of PCR products with DNA electrophoresis. The distributions of vacA alleles were statistically analyzed. The core fragment of vacA was sequentially analyzed by software MEGA4.0. Results The alleles in vacA dominantly belonged to sla, m2 and il in the tested strains.The distribution appeared to be 97.5%(116/119) ,68.9%(82/119) and 91.6%(109/119),respectively.The mlb allele appeared to be 26.1% (31/119). slb and mla were not found. The major vacA recombination was between slaim2/il and 62.2% , followed by sla/mlb/il (25.2% , 30/119). No association was found between the distribution of sla allele and the clinical outcome, as well as the geographical regions (P>0.05). However, the distribution of m alleles showed significant difference both among the types of disease and the geographic regions (P<0.01), The present of i alleles did not show significant differences among disease patterns, but had significant differences between different geographic groups (P<0.01). Three clusters were identified among these 119 isolates according to the DNA sequence of vacA. Conclusion sla/m2/il appeared to be the main allele in H. pylori vacA isolates from China in this study. The distribution of m alleles in vacA was correlated both to the regions and the disease patterns. The presence of i allele was associated to the regions but not the disease patterns.     

Helicobacter pylori and overweight status in the United States: data from the Third National Health and Nutrition Examination Survey

Obesity is an important public health problem in the United States. Because of its potential effects on gastric leptin homeostasis, Helicobacter pylori may play a role in regulating body weight. The authors' aim in this study was to examine the association between H. pylori colonization and overweight status. Nonpregnant participants in the Third National Health and Nutrition Examination Survey (1988-1994) aged > or = 20 years who had had H. pylori testing performed and body mass index (weight (kg)/height (m2)) measured were studied. Overweight was defined as a body mass index greater than or equal to 25. On the basis of serologic results, the participants were categorized into three H. pylori status groups: H. pylori-positive and cytotoxin-associated gene A (cagA)-positive (H. pylori+ cagA+), H. pylori-positive and cagA-negative (H. pylori+ cagA-), and H. pylori-negative (H. pylori-). Of the 7,003 subjects with complete body mass index and H. pylori data, 2,634 (weighted percentage, 22.9%) were H. pylori+ cagA+, 1,385 (15.1%) were H. pylori+ cagA-, and 2,984 (62.0%) were H. pylori-. The adjusted odds of being overweight were 1.17 (95% confidence interval: 0.98, 1.39; p = 0.075) for the H. pylori+ cagA+ group and 0.99 (95% confidence interval: 0.80, 1.22; p = 0.92) for the H. pylori+ cagA- group in comparison with H. pylori- subjects. Serum leptin levels did not differ significantly between the three H. pylori groups. In this US population-based study, there was no significant association between H. pylori colonization, cagA+ strains of H. pylori, and being overweight.     

幽门螺杆菌中国菌株致病相关基因cagA、iceA、vacA及HP0519分布分析

目的分析中国不同人群及不同胃部疾病病例来源的幽门螺杆菌致病相关基因cagA、iceA、vacA及HP0519的分布.方法采用特异引物聚合酶链式反应（PCR）方法分析150株幽门螺杆菌上述基因的多态性分布特点,并对其分布作初步统计分析.结果93%（139/150）中国菌株cagA基因3′端重复序列的PCR产物具有东方菌株特征.75%（113/150）菌株iceA基因为iceA1,19%（29/150）为iceA2,不同地区间iceA基因的分布差异无统计学意义.云南菌株iceA1、iceA2的分布与菌株分离个体的种族特点及临床疾病类型无显著关系.96%中国菌株（144/150）vacA基因s区的等位基因为s1;m区等位基因m2、m1b和m1b-m2的比例分别为57%（85/150）、27%（41/150）和11%（16/150）,仅2株福建菌株为m1a.不同地区间vacA s1、m2、m1b分布的差异无统计学意义.云南菌株m1b-m2的分布高于福建和北京菌株.云南菌株vacA s区等位基因的多样性与分离个体的种族及临床疾病类型无显著关系.vacA m区等位基因的多样性与分离个体的临床疾病类型无显著关系,但不同民族间m2的分布有显著差异,白族人群m2的分布显著少于汉族和纳西族.93%（140/150）的中国菌株HP0519基因具有24 bp和15 bp DNA插入和缺失的多态性特点.不同地区间HP0519基因的多态性无显著不同.云南菌株HP0519的多态性与菌株分离个体的临床疾病类型无显著关系,但来源不同民族菌株的HP0519基因存在差异.结论幽门螺杆菌中国菌株cagA 3′端JF/TR特异引物的扩增结果具有东亚菌株特点.中国菌株vacA基因多为s1,其分布与菌株分离个体的临床疾病类型无关.中国菌株vacA基因m区的分布具有多样性.中国菌株HP0519基因具有24 bp和15 bp插入和缺失的多态性特点.     

球形幽门螺杆菌vacA基因表达质粒构建及表达

目的构建球形幽门螺杆菌vacA基因的重组表达质粒,初步观察其在E.coli中的表达。方法采用亚克隆技术,用BamHⅠ和SacⅠ从重组质粒pMD-18T-vacA上切下vacA基因,插入表达载体pET32a（＋）质粒,转化大肠埃希菌BL21,在氨苄青霉素阳性的LB平板上筛选阳性重组子,并经双酶切及PCR扩增鉴定。重组质粒pET32a（＋）-vacA转化大肠埃希菌,（IPTG）诱导表达后进行（SDS-PAGE）电泳和凝胶扫描定量分析。结果重组质粒酶切和PCR鉴定与预期结果相符,成功构建携带vacA基因的重组原核表达质粒pET32a（＋）-vacA。核酸序列测定及同源性分析证实,表达质粒pET32a（＋）-cagA中所含vacA基因与GenBank中的vacA序列同源性达到99.2%。vacA基因在大肠埃希菌中诱导表达后获得约156 kD蛋白,蛋白含量占全菌体蛋白含量15.5%。结论成功构建球形H.pylori vacA基因重组表达质粒,并获得高效表达,为研究该基因蛋白的生物学特性及DNA疫苗研制奠定了基础。     

Molecular epidemiology, population genetics, and pathogenic role of Helicobacter pylori

Helicobacter pylori infection is linked to various gastroduodenal diseases; however, only approximately 20% of infected individuals develop severe diseases. Despite the high prevalence of H. pylori infection in Africa and South Asia, the incidence of gastric cancer in these areas is much lower than in other countries. Furthermore, the incidence of gastric cancer tends to decrease from north to south in East Asia. Such geographic differences in the pathology can be explained, at least in part, by the presence of different types of H. pylori virulence factors, especially cagA, vacA, and the right end of the cag pathogenicity island. The genotype of the virulence genes is also useful as a tool to track human migration utilizing the high genetic diversity and frequent recombination between different H. pylori strains. Multilocus sequence typing (MLST) analysis using seven housekeeping genes can also help to predict the history of human migrations. Population structure analysis based on MLST has revealed seven modern population types of H. pylori, which derived from six ancestral populations. Interestingly, the incidence of gastric cancer is closely related to the distribution of H. pylori populations. The different incidence of gastric cancer can be partly attributed to the different genotypes of H. pylori circulating in different geographic areas. Although approaches by MLST and virulence factors are effective, these methods focus on a small number of genes and may miss information conveyed by the rest of the genome. Genome-wide analyses using DNA microarray or whole-genome sequencing technology give a broad view on the genome of H. pylori. In particular, next-generation sequencers, which can read DNA sequences in less time and at lower costs than Sanger sequencing, enabled us to efficiently investigate not only the evolution of H. pylori, but also novel virulence factors and genomic changes related to drug resistance.     

幽门螺杆菌cagA基因对胃癌细胞影响

目的观察幽门螺杆菌（Hp）野生株与cagA基因同源缺失突变株对人胃癌细胞株BGC823的细胞增殖和凋亡的影响,探讨与Hp毒力基因cagA相关的细胞水平的毒性效应。方法将幽门螺杆菌野生株与cagA基因缺失突变株与BGC823细胞共培养,分别在6,12,24和48 h观察细胞形态学变化,采用四甲基偶氮噻唑蓝（MTT）比色法检测细胞增殖活性,流式细胞仪检测细胞凋亡情况。结果野生株和突变株Hp攻击BGC823细胞6 h,即可引起细胞的形态学变化,48 h时均可观察到细胞形态呈分散及蜂鸟样改变（细胞拉伸）。MTT法检测显示,野生株对BGC823细胞增殖具有抑制作用,而缺失cagA基因的突变株可刺激细胞增殖,且在24,48 h的2个时间点上均高于对照组和野生株组（P〈0.05）。流式细胞分析显示,在攻击BGC823细胞48 h后,野生株和突变株均可引起细胞凋亡,凋亡率高于对照组（P〈0.05）,2个实验组的凋亡率差异无统计学意义。结论Hp作用后细胞呈分散和蜂鸟样改变（伸长）并不是cagA基因特有的细胞学效应;cagA基因是Hp抑制细胞增值所必需的元素;cagA基因的有无对Hp致凋亡效应的影响不大,在Hp致细胞凋亡的效应中作用可能有限。     

A preliminary study on the genetic profile of cag pathogenicity-island and other virulent gene loci of Helicobacter pylori strains from Turkey.

Helicobacter pylori genetic diversity affects the function and antigenicity of virulence factors associated with the disease outcome. Gene profile was done to identify the distribution of gene loci within and outside the cag pathogenicity-island (PAI). H. pylori strains from 35 patients [21 gastritis, 14 peptic ulcer diseases (PUD)] were analyzed using PCR. The profile of the cag PAI was evaluated using primers spanning the 3' end, cagA, promoter region of the cagA, cagE, cagT, 5' end (LEC), extreme right end, plasticity region open reading frames (ORFs), oipA (Hp0638) and vacA alleles. We found few intact cag PAI in the strains examined. Deletions were found in LEC1 (9.5% versus 14.3%), LEC2 (4.8% versus 14.3%), cagT (33.3% versus 28.6%), cagE (28.6% versus 28.6%) and the promoter region of the cagA (19.0% versus 42.9%) of gastritis and PUD strains, respectively. The cagA gene was detectable in 57.1% of gastritis and 92.9% of PUD-associated strains. The cagRJ region also showed deletions for many of its genes. The oipA (Hp0638) gene was detected in 80.9% of gastritis and in 92.9% of PUD strains. The plasticity region ORFs JHP912 and JHP931 were predominant in PUD strains. The vacA-s1a-m1a genotype was predominant in PUD, while s2m2 in gastritis strains. This comprehensive analysis showed deletions in several genes within and outside the cag PAI. However, cagA, oipA, JHP912, JHP931 and vacA-s1a-m1a were more predominant in PUD strains than gastritis-associated strains, suggesting the importance of genetic diversity on the disease progression and clinical outcome.     

浙江地区幽门螺杆菌临床菌株空泡毒素基因的变异及其表达活性分析

目的 了解浙江地区消化性溃疡(PU)和慢性胃炎(CG)患者感染幽门螺杆菌(Hp)vacA基因的变异及其空泡毒素表达情况。方法 从70株Hp中选择部分菌株测定其vacA基因的s区和m区核苷酸序列。用细胞培养的方法检测Hp菌株的空泡毒性。结果 6株sla型Hp菌株的s区扩增产物与报道的sla型60190株核苷酸序列相似性为93．2％～98．3％，4株m2型Hp菌株的m区扩增产物与报道的m2型87—203株核苷酸序列之间相似性为93．8％～97．6％。1株m1b型Hp菌株的m区扩增产物与报道的m1型60190株相应序列相似性为87．3％，与m2型87—203株相应序列之间相似性为71．7％。所有5株sla／m1型Hp对HeLa、RK-13和SGC-7901三种细胞均有明显的空泡毒作用；仅27.9％(12／43)的sla／m2型菌株对HeLa细胞表现为空泡毒作用，但分别有65．1％(28／43)和62.8％(27／43)的菌株对RK-13细胞和SGC-7901细胞有空泡毒作用。所有sla／m1b和sla／m1b—m2型Hp菌株对三种细胞均有明显的空泡毒作用，以RK-13细胞计，81.0％(17／21)的sla／m1b型Hp菌株和1株sla／m1b—m2型有空泡毒性。PU组感染的Hp菌株空泡毒性(84．4％)强于CG组(60．5％)，差异有统计学意义(P＜0．05)。结论 浙江地区患者感染的Hp菌株vacA基因变异主要在于m区。vacA基因空泡毒性的表达在HeLa细胞中低毒性的sla／m2型菌株在RK-13和SGC-7901细胞中仍有较高的空泡毒性。m1b型Hp空泡毒性强度介于m1和m2型之间。PU患者感染的Hp菌株其空泡毒性明显强于CG组。     

浙江地区幽门螺杆菌优势基因型研究

目的研究浙江地区幽门螺杆菌(Helicobacter pylori,Hp)的优势基因型并探讨各基因在不同胃十二指肠疾病患者中Hp的差异。方法从胃十二指肠疾病患者的胃粘膜活检组织中分离培养到Hp 129株,抽提基因组DNA后用PCR检测Hp的cagA、vacA、iceA及babA2等基因的分布,用卡方检验分析各基因在不同胃十二指肠疾病中Hp的差异。结果129株Hp中cagA的阳性率为99.2%(128/129),vacA sla基因型阳性率为94.6%(122/129),vacA m2为83.7%(108/129),iceA1为84.5%(109/129),iceA2为46.5%(60/129),babA2阳性率为81.4%(105/129)。消化性溃疡患者Hp的vacAm2基因阳性率高于慢性胃炎患者Hp(P<0.05),其余基因在不同类型疾病中的分布无统计学差异(P>0.05)。结论浙江地区Hp菌株的优势基因型为cagA,vacAsla/m2,iceAl,babA2;消化性溃疡患者Hp的vacAm2基因阳性率明显高于慢性胃炎患者。     

幽门螺杆菌感染相关因素的研究进展

幽门螺杆菌（HP）是革兰阴性微需氧的螺旋样杆菌，主要通过口-口途径在人-人之间感染传播。HP的发现加深了人类对慢性感染、炎症和癌症之间关系的认识。其特定的螺旋形体型、鞭毛及动力、尿素酶和黏附素活性，以及细胞毒素基因A（cagA）、空泡细胞毒素基因A（vacA）等是影响HP感染研究较多的相关致病因素。HP感染在胃癌的发生、发展中可能具有重要作用，但尚未确切证实HP感染是导致胃癌的主因。文章概述了HP感染相关致病因素的研究进展。