臺灣博碩士論文加值系統

目前幽門桿菌在全球的感染率已經超過50 ％。幽門桿菌已被認為和罹患胃炎、胃潰瘍及胃腺癌等胃部疾病有相關性，其中，幽門桿菌毒力基因 (如cag A、vac A、ice A) 的基因型差異被推測可能和其致病力有所相關。在臨床上對於幽門桿菌的治療，是採取兩種或以上的抗生素結合鉍 (Bismuth) 或質子幫浦抑制劑 (proton pump inhibitor; PPIs) 的多合一療法。臨床上經常使用的抗生素包含了metronidazole、clarithromycin、rifampin、rifabutin 以及amoxicillin等，但也因臨床上抗生素的廣泛使用，使得幽門桿菌的抗藥性成為臨床治療上的一大問題。但目前幽門桿菌對於amoxicillin具抗藥性的菌株比率仍非常少。本研究由高雄醫學大學附設醫院胃腸內科收集有幽門桿菌感染的臨床患者胃部組織檢體，利用組織研磨萃取DNA以及PCR的方法分析臺灣地區患者所感染幽門桿菌菌株基因型與疾病之相關性，並探討幽門桿菌amoxicillin抗藥機制。結果顯示：所收集的101個檢體中vac A基因型大多為s1 (93.1 ％) 基因型及、m2 (64.4 ％) 基因型，若再分析s1基因型的次基因型的分佈，則以s1c (40.6 ％) 次基因型佔多數；cag A 基因則可在87.1 ％的檢體中偵測到，其中發現所攜帶的cag A 基因皆為東方國家型，而且cag A 基因的3´端重複區域大多為一個FR片段加上1個JSR片段 (73 ％)；另外在ice A基因型上，ice A1 基因型佔58.4 ％，ice A2基因型佔22.8 ％。分析amoxicillin抗藥性菌株之膜蛋白時，發現amoxicillin抗藥菌株PBP 1 結合biotin標誌的amoxicillin之能力下降，進而造成菌株對amoxicillin產生抗藥性，也發現抗藥菌株對多種藥物產生交互抗藥性。此外，amoxicillin抗藥性臨床分離菌株發現具beta-lactamase活性。
根據此實驗結果發現，vac A、cag A及ice A基因型的分佈和罹患胃炎及胃潰瘍並無統計上的相關性。幽門桿菌PBP基因突變及beta-lactamase的產生是導致對amoxicillin高抗藥性的重要機制。

Nowadays, the overall infection rate of Helicobacter pylori (H. pylori) infection is over 50 ％. H. pylori is accepted as the causative agent of gastritis, peptic ulcer disease, and gastric cancer. The relationship between the subtypes of cagA, vac A, ice A and H. pylori related gastric disease was considered. Nowadays, successful treatment of H. pylori infection require a combination of drugs, including two or more antibiotics in combination with bismuth component or proton pump inhibitor (PPIs). Metronidazole, clarithromycin, rifampin, rifabutin, tetracycline, and amoxicillin are the most widely used antibiotics for the treatment of H. pylori infection. However, the development of antimicrobial resistance was leading to serious problems for treatment. At present, amoxicillin resistance in H. pylori is rare. In this study, by using PCR method, the relationship between subtypes of cag A, vac A, and ice A of H. pylori isolated from patients with gastric disease in Chung-Ho Memorial Hospital, Kaohsiung medical university was analysed. In addition, the mechanism of amoxicillin resistance was evaluated. Results showed that in 101 isolates, the vac A s1,m2 genotypes was detected in 93.1 ％ and 64.4 ％, respectively. Furthermore, vac A s1c subtype (40.6 ％) was predominant；87.1 ％ strains with cag A gene was east asian type. In addition,73 ％ of the strains had one FR and one JSR regions in 3´ repeat region of cag A. Fifty-eight percent of our cases were positive for ice A1, and 22.8 ％ for ice A2. Analysis of the PBP profiles generated from isolated bacterial membrane of the amoxicillin resistant strains revealed a significant decrease in labeling of PBP 1 by biotinylated amoxicillin, resulting in resistance to this antibiotic and conferred cross-resistance to other antibiotics. In addition, beta-lactamase activity was detected in clinical isolate of amoxicillin resistant strain. In conclusion, the relationships between H. pylori vac A, cag A, and ice A genotypes with the presence of gastritis and gastric ulcer were not found. Mutations in PBP and beta-lactamase activity in H. pylori were considered as important mechanisms that contribute to higher level of amoxicillin resistance.

中文摘要 …………………………………………………………… 1
英文摘要 …………………………………………………………… 3
前言 ………………………………………………………………… 5
一、 幽門桿菌 …………………………………………………… 5
二、 幽門桿菌的感染 …………………………………………… 5
三、 幽門桿菌的毒力因子 ……………………………………… 6
四、 基因型與疾病之相關性 …………………………………… 9
五、 幽門桿菌感染之臨床治療方法 …………………………… 10
六、 幽門桿菌抗藥性之產生 …………………………………… 10
七、 amoxicillin抗藥機制之研究 …………………………… 12
八、 研究目的 …………………………………………………… 15
材料與方法 ………………………………………………………… 16
（一） 病患檢體 …………………………………………… 16
（二） 幽門桿菌分離菌株及其培養方法……………………16
（三） 由胃部組織萃取模版DNA…………………………… 17
（四） 幽門桿菌DNA之製備 ……………………………… 18
（五） 聚合酶連鎖反應 …………………………………… 18
（六） 瓊脂醣明膠電泳(agarose gel electrophoresis)…20
（七） 基因型結果判讀 ……………………………………21
（八） 統計分析 ……………………………………………24
（九） 最小抑菌濃度(Minimal Inhibitory concentration，MIC值)的測定 ………………… 24
（十） 乙內醯胺酶（beta-lactamase）活性測定 ……… 25
（十一） 幽門桿菌膜蛋白的製備 …………………………… 26
（十二） 膜蛋白之蛋白質濃度測定 ………………………… 27
（十三） 標記生物素之ampicillin (Bio-AMP：Biotin-
ampicillin)/標記生物素之amoxicillin (BIO-AMO：
Biotin-amoxicillin)的製備 …………………… 28
（十四） 青黴素結合蛋白（penicillin-binding protein ，PBP）的表現 ………………………………………… 28
（十五） BIO-AMP/BIO-AMO與青黴素結合蛋白（PBP）的結合… 30
（十六） BIO-AMP/BIO-AMO與ampicillin/ amoxicillin對青
黴素結合蛋白的競爭結合 …………………………… 33
（十七） 自然轉形作用(natural transformation) ………… 33
結果 ………………………………………………………………… 35
（一） 基因型結果判讀 ………………………………………… 35
（二） 基因型與疾病的相關性 ………………………………… 37
（三） 最小抑菌濃度(MIC值)的測定 ………………………… 41
（四） 乙內醯胺酶(beta-lactamase)活性測定 ……………… 42
（五） 青黴素結合蛋白（PBP）的表現 ………………………… 42
（六） BIO-AMP/BIO-AMO與青黴素結合蛋白（PBP）的結合…… 42
（七） BIO-AMP/BIO-AMO與ampicillin/ amoxicillin對青黴素結合蛋白的競爭結合 …………………………… 43
（八） 自然轉形作用 …………………………………………… 44
討論 ………………………………………………………………… 45
參考文獻 …………………………………………………………… 53
表次 ………………………………………………………………… 61
表一 引子組 …………………………………………………… 61
表二 以PCR增幅幽門桿菌青黴素結合蛋白PBP 1特定片段的引子組 ………………………………………………………64
表三 幽門桿菌菌株vac A, cag A, ice A基因型分佈 ……… 65
表四 幽門桿菌菌株vac A次基因型分佈 …………………… 66
表五 最低抑菌濃度(MIC值)及乙內醯胺酶(beta-lactamase)
活性測定 ………………………………………………… 67
圖次 ………………………………………………………………… 68
圖一 以PCR增幅幽門桿菌青黴素結合蛋白PBP 1的特定
片段 ……………………………………………………… 68
圖二 青黴素結合蛋白（PBP）的表現及BIO-AMP/BIO-AMO與青黴素結合蛋白（PBP）的結合 …………………………… 69
圖三 BIO-AMP與ampicillin對青黴素結合蛋白的競爭結合… 70
圖四 BIO-AMO與amoxicillin對青黴素結合蛋白的競爭結合…71
圖五 自然轉形作用 …………………………………………… 72
附圖次 ……………………………………………………………… 73
附圖一 cag A基因3´端的基因結構 ………………………… 73

1.Achtman M, Azuma T, Berg DE, Ito Y, Morelli G, Pan ZJ, Suerbaum S, Thompson SA, van der Ende A, van Doorn LJ.1999. Recombination and clonal groupings within Helicobacter pylori from different geographical regions. Mol Microbiol. 32:459-470.
2.Akopyanz N, Bukanov NO, Westblom TU, Kresovich S, Berg DE. 1992. DNA diversity among clinical isolates of Helicobacter pylori detected by PCR-based RAPD fingerprinting. Nucleic Acids Res. 20:5137-5142.
3.Atherton JC, Cao P, Peek RM Jr, Tummuru MK, Blaser MJ, Cover TL. 1995. Mosaicism in vacuolating cytotoxin alleles of Helicobacter pylori. Association of specific vacA types with cytotoxin production and peptic ulceration. J Biol Chem. 270:17771-17777.
4.Atherton JC, Peek RM Jr, Tham KT, Cover TL, Blaser MJ. 1997. Clinical and pathological importance of heterogeneity in vacA, the vacuolating cytotoxin gene of Helicobacter pylori. Gastroenterology. 112:92-99.
5.Blaser MJ, Perez-Perez GI, Kleanthous H, Cover TL, Peek RM, Chyou PH, Stemmermann GN, Nomura A. 1995. Infection with Helicobacter pylori strains possessing cagA is associated with an increased risk of developing adenocarcinoma of the stomach. Cancer Res. 55:2111-2115.
6.Chen XJ, Yan J, Shen YF. 2005. Dominant cagA/vacA genotypes and coinfection frequency of H. pylori in peptic ulcer or chronic gastritis patients in Zhejiang Province and correlations among different genotypes, coinfection and severity of the diseases. Chin Med J (Engl). 118:460-467.
7.Ching CK, Wong BC, Kwok E, Ong L, Covacci A, Lam SK. 1996. Prevalence of CagA-bearing Helicobacter pylori strains detected by the anti-CagA assay in patients with peptic ulcer disease and in controls. Am J Gastroenterol. 91:949-953.
8.Chopra I, Roberts M. 2001. Tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistance. Microbiol Mol Biol Rev. 65:232-260.
9.Covacci A, Censini S, Bugnoli M, Petracca R, Burroni D, Macchia G, Massone A, Papini E, Xiang Z, Figura N, et al. 1993. Molecular characterization of the 128-kDa immunodominant antigen of Helicobacter pylori associated with cytotoxicity and duodenal ulcer. Proc Natl Acad Sci U S A. 90:5791-5795.
10.Cover TL. 1996. The vacuolating cytotoxin of Helicobacter pylori. Mol Microbiol. 20:241-246.
11.Cover TL , Blaser MJ 1992. Purification and characterization of the vacuolating toxin from Helicobacter pylori. J. Biol. Chem 267:10570-10575.
12.Cover TL, Tummuru MK, Cao P, Thompson SA, Blaser MJ. 1994. Divergence of genetic sequences for the vacuolating cytotoxin among Helicobacter pylori strains. J Biol Chem. 269:10566-10573.
13.Letley DP, Lastovica A, Louw JA, Hawkey CJ, Atherton JC.1999. Allelic Diversity of the Helicobacter pylori Vacuolating Cytotoxin Gene in South Africa: Rarity of the vacA s1a Genotype and Natural Occurrence of an s2/m1 Allele. J. Clin. Microbiol. 37:1203-1205.
14.Dargis M, Malouin F.1994. Use of biotinylated beta-lactams and chemiluminescence for study and purification of penicillin-binding proteins in bacteria. Antimicrob Agents Chemother. 38:973-980.
15.DeLoney CR, Schiller NL. 2000. Characterization of an In vitro-selected amoxicillin-resistant strain of Helicobacter pylori. Antimicrob Agents Chemother. 44:3368-3373.
16.DeLoney CR, Schiller NL. 1999. Competition of various beta-lactam antibiotics for the major penicillin-binding proteins of Helicobacter pylori: antibacterial activity and effects on bacterial morphology. Antimicrob Agents Chemother. 43:2702-2709.
17.Rothenbacher D, Brenner H. 2003. Burden of Helicobacter pylori and H. pylori-related diseases in developed countries: recent developments and future implications. . Microbes and Infection 5:693-703
18.Dore MP, Graham DY, Sepulveda AR. 1999. Different penicillin-binding protein profiles in amoxicillin-resistant Helicobacter pylori. Helicobacter. 4:154-161.
19.Dunn BE, Cohen H, Blaser MJ. 1997. Helicobacter pylori. Clin. Microbiol. Rev. 10:720-741.
20.Erzin Y, Koksal V, Altun S, Dobrucali A, Aslan M, Erdamar S, Dirican A, Kocazeybek B. 2006. Prevalence of Helicobacter pylori vacA, cagA, cagE, iceA, babA2 genotypes and correlation with clinical outcome in Turkish patients with dyspepsia. Helicobacter. 11:574-580.
21.Farinha P, Gascoyne RD. 2005. Helicobacter pylori and MALT lymphoma. Gastroenterology. 128:1579-1605.
22.Figueiredo C, Van Doorn LJ, Nogueira C, Soares JM, Pinho C, Figueira P, Quint WG, Carneiro F. 2001. Helicobacter pylori genotypes are associated with clinical outcome in Portuguese patients and show a high prevalence of infections with multiple strains. Scand J Gastroenterol. 36:128-135.
23.Gatti LL, Fagundes e Souza EK, Leite KR, Bastos EL, Vicentini LR, Silva LC, Smith Mde A, Payao SL. 2005. cagA vacA alelles and babA2 genotypes of Helicobacter pylori associated with gastric disease in Brazilian adult patients. Diagn Microbiol Infect Dis. 51:231-235.
24.Gerrits MM, Godoy AP, Kuipers EJ, Ribeiro ML, Stoof J, Mendonca S, van Vliet AH, Pedrazzoli J Jr, Kusters JG. 2006. Multiple mutations in or adjacent to the conserved penicillin-binding protein motifs of the penicillin-binding protein 1A confer amoxicillin resistance to Helicobacter pylori. Helicobacter. 11:181-187.
25.Gerrits MM, Schuijffel D, van Zwet AA, Kuipers EJ, Vandenbroucke-Grauls CM, Kusters JG. 2002. Alterations in penicillin-binding protein 1A confer resistance to beta-lactam antibiotics in Helicobacter pylori. Antimicrob Agents Chemother. 46:2229-2233.
26.Glupczynski Y, Megraud F, Lopez-Brea M, Andersen LP. 2001. European multicentre survey of in vitro antimicrobial resistance in Helicobacter pylori. Eur J Clin Microbiol Infect Dis. 20:820-823.
27.Go MF, Kapur V, Graham DY, Musser JM. 1996. Population genetic analysis of Helicobacter pylori by multilocus enzyme electrophoresis: extensive allelic diversity and recombinational population structure. J Bacteriol. 178:3934-3938.
28.Goldman RC, Zakula D, Flamm R, Beyer J, Capobianco J. 1994. Tight binding of clarithromycin, its 14-(R)-hydroxy metabolite, and erythromycin to Helicobacter pylori ribosomes. Antimicrob Agents Chemother. 38:1496-1500.
29.Grebe T, Hakenbeck R. 1996. Penicillin-binding proteins 2b and 2x of Streptococcus pneumoniae are primary resistance determinants for different classes of beta-lactam antibiotics. Antimicrob Agents Chemother. 40:829-834.
30.Harris AG, Hazell SL, Netting AG. 2000. Use of digoxigenin-labelled ampicillin in the identification of penicillin-binding proteins in Helicobacter pylori. J Antimicrob Chemother. 45:591-598.
31.Hirata Y, Yanai A, Shibata W, Mitsuno Y, Maeda S, Ogura K, Yoshida H, Kawabe T, Omata M. 2004. Functional variability of cagA gene in Japanese isolates of Helicobacter pylori. Gene. 343:165-172.
32.Hou P, Tu ZX, Xu GM, Gong YF, Ji XH, Li ZS. 2000. Helicobacter pylori vacA genotypes and cagA status and their relationship to associated diseases. World J Gastroenterol. 6:605-607.
33.Huang AH, Sheu BS, Yang HB, Huang CC, Wu JJ, Lin XZ. 2000. Impact of Helicobacter pylori antimicrobial resistance on the outcome of 1-week lansoprazole-based triple therapy. J Formos Med Assoc. 99:704-709.
34.Ikeda F, Yokota Y, Mine Y, Tatsuta M. 1990. Activity of cefixime against Helicobacter pylori and affinities for the penicillin-binding proteins. Antimicrob Agents Chemother. 34:2426-2428.
35.Kusters JG, van Vliet AH, Kuipers EJ. 2006. Pathogenesis of Helicobacter pylori Infection. Clinical Microbiology Reviews 19:449-490.
36.Murakami K, Kodama M, Fujioka T. 2006. Latest insights into the effects of Helicobacter pylori infection on gastric carcinogenesis. World J Gastroenterol 12:2713-2720.
37.Kim JJ, Reddy R, Lee M, Kim JG, El-Zaatari FA, Osato MS, Graham DY, Kwon DH. 2001. Analysis of metronidazole, clarithromycin and tetracycline resistance of Helicobacter pylori isolates from Korea. J Antimicrob Chemother. 47:459-461.
38.Krishnamurthy P, Parlow MH, Schneider J, Burroughs S, Wickland C, Vakil NB, Dunn BE, Phadnis SH. 1999. Identification of a novel penicillin-binding protein from Helicobacter pylori. J Bacteriol. 181:5107-5110.
39.Kwon DH, Dore MP, Kim JJ, Kato M, Lee M, Wu JY, Graham DY. 2003. High-level beta-lactam resistance associated with acquired multidrug resistance in Helicobacter pylori. Antimicrob Agents Chemother. 47:2169-2178.
40.Kwon DH, El-Zaatari FA, Kato M, Osato MS, Reddy R, Yamaoka Y, Graham DY. 2000. Analysis of rdxA and involvement of additional genes encoding NAD(P)H flavin oxidoreductase (FrxA) and ferredoxin-like protein (FdxB) in metronidazole resistance of Helicobacter pylori. Antimicrob Agents Chemother. 44:2133-2142.
41.Lee N, Yuen KY, Kumana CR. 2003. Clinical role of beta-lactam/beta-lactamase inhibitor combinations. Drugs. 63:1511-1524.
42.van Doorn LJ, Figueiredo C, Sanna R, Pena S, Midolo P, Ng EK, Atherton JC, Blaser MJ, Quint WG. 1998. Expanding Allelic Diversity of Helicobacter pylori vacA. J. Clin. Microbiol. 36:2597-2603.
43.Van Doorn LJ, Figueiredo C, Megraud F, Pena S, Midolo P, Queiroz DM, Carneiro F, Vanderborght B, Pegado MD, Sanna R, De Boer W, Schneeberger PM, Correa P, Ng EK, Atherton J, Blaser MJ, Quint WG. 1999. Geographic distribution of vacA allelic types of Helicobacter pylori. Gastroenterology . 116:823-830.
44.Lin CW, Wu SC, Lee SC, Cheng KS. 2000. Genetic analysis and clinical evaluation of vacuolating cytotoxin gene A and cytotoxin-associated gene A in Taiwanese Helicobacter pylori isolates from peptic ulcer patients. Scand J Infect Dis. 32:51-57.
45.Lin HJ, Perng CL, Lo WC, Wu CW, Tseng GY, Li AF, Sun IC, Ou YH. 2004. Helicobacter pylori cagA, iceA and vacA genotypes in patients with gastric cancer in Taiwan. World J Gastroenterol. 10:2493-2497.
46.Ling TK, Leung WK, Lee CC, Ng EK, Yung MY, Chung SS, Sung JJ, Cheng AF. 2002. The antimicrobial susceptibility of Helicobacter pylori in Hong Kong (1997-2001). Helicobacter. 7:327-328.
47.Blaser MJ, Atherton JC. 2004. Helicobacter pylori persistence: biology and disease. Journal of Clinical Investigation 113:321-333.
48.Martins LC, Corvelo TC, Demachki S, Araujo MT, Assumpcao MB, Vilar SC, Freitas FB, Barbosa HP, Fecury AA, do Amaral RK, Dos Santos SE. 2005. Clinical and pathological importance of vacA allele heterogeneity and cagA status in peptic ulcer disease in patients from North Brazil. Mem Inst Oswaldo Cruz. 100:875-881.
49.Megraud F. 2004. H. pylori antibiotic resistance: prevalence, importance, and advances in testing. Gut. 53:1374-1384.
50.Miehlke S, Kirsch C, Agha-Amiri K, Gunther T, Lehn N, Malfertheiner P, Stolte M, Ehninger G, Bayerdorffer E. 2000. The Helicobacter pylori vacA s1, m1 genotype and cagA is associated with gastric carcinoma in Germany. Int J Cancer. 87:322-327.
51.Miehlke S, Kibler K, Kim JG, Figura N, Small SM, Graham DY, Go MF. 1996. Allelic variation in the cagA gene of Helicobacter pylori obtained from Korea compared to the United States. Am J Gastroenterol. 91:1322-1325.
52.Mukhopadhyay AK, Kersulyte D, Jeong JY, Datta S, Ito Y, Chowdhury A, Chowdhury S, Santra A, Bhattacharya SK, Azuma T, Nair GB, Berg DE 2000. Distinctiveness of genotypes of Helicobacter pylori in Calcutta, India. J Bacteriol. 182:3219-3227.
53.Neuwirth C, Siebor E, Duez JM, Pechinot A, Kazmierczak A. 1995. Imipenem resistance in clinical isolates of Proteus mirabilis associated with alterations in penicillin-binding proteins. J Antimicrob Chemother. 36:335-342.
54.Georgopapadakou NH. 1993. Penicillin-binding proteins and bacterial resistance to beta-lactams. Antimicrob Agents Chemother. 37:2045-2053.
55.Nikaido H. 2000. Crossing the envelope: how cephalosporins reach their targets. Clin Microbiol Infect. 6:22-26.
56.Nikaido H. 1994. Prevention of drug access to bacterial targets: permeability barriers and active efflux. Science. 264:382-387.
57.Okamoto T, Yoshiyama H, Nakazawa T, Park ID, Chang MW, Yanai H, Okita K, Shirai M. 2002. A change in PBP1 is involved in amoxicillin resistance of clinical isolates of Helicobacter pylori. J Antimicrob Chemother. 50:849-856.
58.Osato MS, Reddy R, Reddy SG, Penland RL, Malaty HM, Graham DY. 2001. Pattern of primary resistance of Helicobacter pylori to metronidazole or clarithromycin in the United States. Arch Intern Med. 161:1217-1220.
59.Parr TR Jr, Bryan LE. 1984. Mechanism of resistance of an ampicillin-resistant, beta-lactamase-negative clinical isolate of Haemophilus influenzae type b to beta-lactam antibiotics. Antimicrob Agents Chemother. 25:747-753.
60.Parsonnet J, Friedman GD, Orentreich N, Vogelman H. 1997. Risk for gastric cancer in people with CagA positive or CagA negative Helicobacter pylori infection. Gut. 40:297-301.
61.Paul R, Postius S, Melchers K, Schafer KP. 2001. Mutations of the Helicobacter pylori genes rdxA and pbp1 cause resistance against metronidazole and amoxicillin. Antimicrob Agents Chemother. 45:962-965.
62.Paul TR, Halligan NG, Blaszczak LC, Parr TR Jr, Beveridge TJ. 1992. A new mercury-penicillin V derivative as a probe for ultrastructural localization of penicillin-binding proteins in Escherichia coli. J Bacteriol. 174:4689-4700.
63.Peek RM Jr, Thompson SA, Donahue JP, Tham KT, Atherton JC, Blaser MJ, Miller GG. 1998. Adherence to gastric epithelial cells induces expression of a Helicobacter pylori gene, iceA, that is associated with clinical outcome. Proc Assoc Am Physicians. 110:531-544.
64.Perez Aldana L, Kato M, Nakagawa S, Kawarasaki M, Nagasako T, Mizushima T, Oda H, Kodaira J, Shimizu Y, Komatsu Y, Zheng R, Takeda H, Sugiyama T, Asaka M. 2002. The relationship between consumption of antimicrobial agents and the prevalence of primary Helicobacter pylori resistance. Helicobacter. 7:306-309.
65.Perng CL, Lin HJ, Sun IC, Tseng GY, Facg. 2003. Helicobacter pylori cagA, iceA and vacA status in Taiwanese patients with peptic ulcer and gastritis. J Gastroenterol Hepatol. 18:1244-1249.
66.Eslick GD. 2006. Helicobacter pylori infection causes gastric cancer? A review of the epidemiological, meta-analytic, and experimental evidence. World J Gastroenterol 12:2991-2999.
67.Frenck RW Jr, Clemens J. 2003. Helicobacter in the developing world. . Microbes and Infection 5:705-713
68.Rudi J, Kolb C, Maiwald M, Kuck D, Sieg A, Galle PR, Stremmel W. 1998. Diversity of Helicobacter pylori vacA and cagA genes and relationship to VacA and CagA protein expression, cytotoxin production, and associated diseases. J Clin Microbiol. 36:944-948.
69.Smith MA, Edwards DI. 1997. Oxygen scavenging, NADH oxidase and metronidazole resistance in Helicobacter pylori. J Antimicrob Chemother. 39:347-353.
70.Suerbaum S, Michetti P. 2002. Helicobacter pylori infection. N Engl J Med. 347:1175-1186.
71.Taylor DN , Blaser MJ. 1991. The epidemiology of Helicobacter pylori infection. Epidemiol Rev. 13:42-59.
72.Tummuru MK, Cover TL, Blaser MJ. 1993. Cloning and expression of a high-molecular-mass major antigen of Helicobacter pylori: evidence of linkage to cytotoxin production. Infect Immun. 61:1799-1809.
73.van Doorn LJ, Figueiredo C, Sanna R, Plaisier A, Schneeberger P, de Boer W, Quint W. 1998. Clinical relevance of the cagA, vacA, and iceA status of Helicobacter pylori. Gastroenterology. 115:58-66.
74.Wang HJ, Kuo CH, Yeh AA, Chang PC, Wang WC. 1998. Vacuolating toxin production in clinical isolates of Helicobacter pylori with different vacA genotypes. J Infect Dis. 178:207-212.
75.Warren JR, Marshall B. 1983. Unidentified curved bacilli on gastric epithelium in active chronic gastritis. Lancet. 321:1273-1275.
76.Wong BC, Yin Y, Berg DE, Xia HH, Zhang JZ, Wang WH, Wong WM, Huang XR, Tang VS, Lam SK. 2001. Distribution of distinct vacA, cagA and iceA alleles in Helicobacter pylori in Hong Kong. Helicobacter. 6:317-324.
77.Wu CC, Chou PY, Hu CT, Liu ZC, Lin CY, Tseng YH, Lin NT. 2005. Clinical Relevance of the vacA, iceA, cagA, and flaA genes of Helicobacter pylori strains isolated in Eastern Taiwan. J Clin Microbiol. 43:2913-2915.
78.Xiang Z, Censini S, Bayeli PF, Telford JL, Figura N, Rappuoli R, Covacci A. 1995. Analysis of expression of CagA and VacA virulence factors in 43 strains of Helicobacter pylori reveals that clinical isolates can be divided into two major types and that CagA is not necessary for expression of the vacuolating cytotoxin. Infect Immun. 63:94-98.
79.Yamaoka Y, Kodama T, Gutierrez O, Kim JG, Kashima K, Graham DY. 1999. Relationship between Helicobacter pylori iceA, cagA, and vacA status and clinical outcome: studies in four different countries. J Clin Microbiol. 37:2274-2279.
80.Yamaoka Y, Kodama T, Kashima K, Graham DY, Sepulveda AR. 1998. Variants of the 3'' region of the cagA gene in Helicobacter pylori isolates from patients with different H. pylori-associated diseases. J Clin Microbiol. 36:2258-2263.
81.Yamaoka Y, Kodama T, Kita M, Imanishi J, Kashima K, Graham DY. 1998. Relationship of vacA genotypes of Helicobacter pylori to cagA status, cytotoxin production, and clinical outcome. Helicobacter. 3:241-253.
82.Yamaoka Y, El-Zimaity HM, Gutierrez O, Figura N, Kim JG, Kodama T, Kashima K, Graham DY. 1999. Relationship between the cagA 3'' repeat region of Helicobacter pylori, gastric histology, and susceptibility to low pH. . Gastroenterology 117:342-349.
83.Zhang MJ, He LH, Wong BC, Zhou ZF, Zhang JZ. 2006. Distribution of cagA 3'' region, iceA, vacA and HP0519 on Helicobacter pylori isolated from China. Zhonghua Liu Xing Bing Xue Za Zhi. 27:508-512.
84.Zhang Y, Liu H, Zhou K. 2001. Lack of correlation of vacA genotype, cagA gene of Helicobacter pylori and their expression products with various gastroduodenal diseases. Chin Med J (Engl). 114:703-706.
85.Zhou ZF, Dai W, Zhang JZ, Nan Q, Zhang JW, Wang J, Jin L, He ZY, Tao ZY, Mu JH. 2005. Infection of Helicobacter pylori strains with multiple vacA m-region subtypes and/or iceA mixed genotype among the Bai, Naxi, and Han populations in Yunnan province. Zhonghua Yi Xue Za Zhi. 85:2408-2413.