贵阳地区幽门螺杆菌临床分离株中ureA、cagA、vacA、iceA基因的分布及分析

目的了解贵阳地区临床分离的幽门螺杆菌（Hp）的毒力基因ureA、cagA、vacA、iceA的分布特征,探讨不同毒力基因型与上消化道疾病的关系。方法用特异的16SrDNA聚合酶链反应进行临床分离Hp的菌种鉴定,对经过鉴定的152株幽门螺杆菌进行ureA、cagA、vacA、iceA基因及亚型的PCR检测。结果 ureA基因的检出率为100%（152/152）,vacA基因的检出率为100%（152/152）,vacA基因亚型以s1a-m2型为主,占76.3%（116/152）,cagA基因检出率为39.5%（60/152）,ieeA1基因检出率36.8%（56/152）,iceA2基因检出率为34.2%（52/152）,13.2%（20/152）的菌株iceA1和iceA2基因均阳性,不同基因型菌株在慢性胃炎和消化性溃疡中的检出率无统计学意义（P〉0.05）。结论贵阳地区幽门螺杆菌毒力基因vacA以s1a-m2型为主,cagA阴性比例高于cagA阳性,不同基因型菌株与消化性疾病间无明显相关性。     

幽门螺杆菌cagA及vacA亚型与胃肠疾病的关系

目的调查石家庄地区慢性胃病患者感染幽门螺杆菌(H·pylori)的细胞毒素相关基因(cagA)及空泡毒素基因(vacA)亚型的流行情况;探讨H·pylori cagA、vacA亚型与胃肠疾病的关系。方法自石家庄地区慢性胃病患者胃黏膜中分离得到55株H·pylori,抽提各菌株的总DNA,采用特定引物对各菌株cagA3′端、vacA信号序列(s)及中间序列(m)进行PCR检测。结果H·pylori cagA的阳性者占89·1%(49/55),其在慢性胃炎和消化性溃疡中的阳性率差异无显著性(χ2=0·376,P=0·540)。H·pylori vacA基因亚型有s1a/m2、s1a/m1b-m2、s1a/m1b三种组合,各亚型所占比例分别为90·4%(47/52)、5·8%(3/52)、3·8%(2/52),其中最常见的vacA亚型s1a/m2在慢性胃炎与消化性溃疡中的阳性率差异无显著性(χ2=0,P=1·000)结论石家庄地区慢性胃病患者感染的幽门螺杆菌以cagA 、vacA s1a/m2亚型占优势,未发现H·pylori cagA及vacA亚型与特定胃肠疾病间存在显著相关性。     

外周血幽门螺杆菌DNA的检测

目的　探讨幽门螺杆菌是否可导致菌血症。方法　采用聚合酶链反应(PCR)对2 0例消化性溃疡及慢性胃炎患者的外周血和胃黏膜组织进行幽门螺杆菌DNA检测,并对胃黏膜组织进行幽门螺杆菌分离培养。结果　在2 0个病例中,9例胃黏膜组织分离培养出了幽门螺杆菌,15例胃黏膜组织PCR扩增出幽门螺杆菌DNA ;2 0份外周血标本中有3份PCR扩增出幽门螺杆菌DNA ,其16SrRNA、cagA基因为阳性,该3例患者的胃黏膜组织也扩增出了幽门螺杆菌DNA ,并分离培养出幽门螺杆菌。结论　幽门螺杆菌不仅存在于胃黏膜组织中,也可存在于血液中,提示幽门螺杆菌可引起菌血症。     

原发性肝癌组织中螺杆菌属16S rRNA基因的检测及意义

目的探讨原发性肝癌（HCC）组织中螺杆菌感染情况。方法选取经病理诊断的28例HCC患者的肝癌组织为实验组，22例非肝癌肝病患者肝组织和25例胃癌患者胃癌组织作对照组。采用聚合酶链反应（PCR）扩增螺杆菌属16S rRNA基因、幽门螺杆菌相关功能基因空泡毒素基因（vacA）和细胞毒素相关基因（cagA），16S rRNA的扩增产物经Southern杂交确认，并将PCR产物进行测序及同源性比较。结果28例HCC标本中有17例检出螺杆菌属16S rRNA基因，阳性率为60．7％；25例胃癌标本有18例检出螺杆菌16S rRNA，阳性率为72．0％；其他肝病组未扩增出16S rRNA基因。16Sr RNA PCR产物经Southern杂交证实为幽门螺杆菌。序列测定表明，肝癌和胃癌组织中的螺杆菌16S rRNA序列与幽门螺杆菌序列有97．8％的同源性。肝癌组相关功能基因有3例cagA基因阳性，胃癌组有2例cagA基因阳性，均未扩增出VacA基因。提示，幽门螺杆菌菌株的基因型多为Ⅱ型，而少数为Ⅰ型。结论HCC患者肝组织中存在螺杆菌感染且感染率较高。螺杆菌感染与HCC可能存在相关性。     

肝癌患者肝组织中螺杆菌感染的研究

目的　探讨螺杆菌感染是否与人类肝癌的发生相关。方法　选取经病理诊断的肝癌组织及癌旁组织 2 0例为研究对象 ,非肝癌组织 16例作对照 ,采用聚合酶链反应 (PCR)扩增螺杆菌 16SrRNA基因 (16SrDNA)检测螺杆菌 ,扩增产物经Southern杂交证实 ,并对部分标本的PCR产物进行测序及同源比较。阳性者再扩增幽门螺杆菌 (H pylori)的特异基因 (2 6 -kDa蛋白 )和相关功能基因 (cagA、vacA、glmM、rps4 )来验证是否为该菌。结果　 4 0 % (8/ 2 0 )的肝癌组织中发现螺杆菌 16SrD NA存在 ,其对应的癌旁组织大部分亦阳性 (7/ 8) ,而非肝癌组无一例阳性 (P <0 0 1)。所有PCR产物用Southern杂交得到证实。 6例测序及同源比较显示 ,肝癌组织中的螺杆菌 16SrDNA序列与H pylori的 16SrDNA序列有 98 5 %～ 99 0 %的同源性。阳性标本中 2 6 -kDa基因大部分亦阳性 (7/ 8) ,但仅 2例扩增出cagA基因 ,2例扩增出glmM基因 ,一直未扩增出vacA基因和rps4基因。 结论　肝癌患者肝组织中螺杆菌感染率较高 ,它与肝癌的发生可能存在某种联系。     

河西走廊地域幽门螺杆菌vacA和cagA基因型分布研究

[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(P0.05)。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(P0.05)。[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。     

幽门螺杆菌iceA、cagA相关性研究

目的研究幽门螺杆菌(Helicobecterpylori)cagA、iceA与胃十二指肠疾病的关系及二者的相关性。方法从138例胃黏膜活检组织中分离培养H·pylori,PCR扩增检测cagA、iceA,并测序。结果cagA /iceA1 /iceA2 在消化性溃疡中的阳性率明显高于慢性胃炎和胃癌。cagA、iceA1同时阳性为55·4%(62/112),cagA阴性iceA1阳性为11·5%(3/26),存在统计学差异。cagA、iceA2同时阳性为51·8%(58/112),cagA阴性iceA2阳性为30·8%(8/26),存在统计学差异。结论cagA /iceA1 /iceA2 菌株可能与消化性溃疡的发生、发展相关,cagA和iceA1可能存在协同作用,和iceA2关系不大。     

肝螺杆菌多重PCR检测方法的建立及应用

目的建立肝螺杆菌的多重PCR检测方法,对中国动物肝螺杆菌进行检测。方法以毒力基因flaB基因、ureA基因和cdtB基因和cdtC基因作为靶基因,建立检测肝螺杆菌的多重PCR方法。对肝螺杆菌、空肠弯曲菌、幽门螺杆菌、沙门氏菌、志贺氏菌、小肠结肠炎耶尔森菌、大肠埃希氏菌和铜绿假单胞杆菌抽提的DNA进行多重PCR扩增。应用本研究建立的多重PCR检测方法对482只动物(其中:海南30只猴、江苏34只小鼠和北京32只猴、30头猪、66只犬、13只兔、29只豚鼠、69只大鼠、213只小鼠)进行检测,对扩增出的阳性结果进行测序。同时,对所有样本采用选择性培养基进行肝螺杆菌培养以作对照。结果肝螺杆菌能扩增出各自的特异性条带,而其他参考菌株均未扩增出条带,这表明该方法具有较强的特异性。482份样本中检出43份肝螺杆菌阳性样本,阳性率8.92%(43/482),其中:2只犬(3.03%,2/66)、1只兔(7.69%,1/13)、5只大鼠(7.25%,5/69)和35只小鼠(16.43%,35/247)均扩增出肝螺杆菌毒力基因片段。结果显示,肝螺杆菌flaB基因、ureA基因和cdtB基因和cdtC基因序列与GenBank中的肝螺杆菌ATCC51449的相应基因序列核苷酸同源性高达99%。用选择性培养基能培养出肝螺杆菌。结论中国动物中的犬、兔、大鼠和小鼠均能检出肝螺杆菌flaB基因、ureA基因、cdtB基因和cdtC基因。建立的多重PCR检测方法可作为肝螺杆菌大规模检测的新技术,这为在中国开展肝螺杆菌流行病学调查提供了有效科学工具。     

西安地区幽门螺杆菌cagA, iceA基因与其所致疾病的相关性

目的: 研究幽门螺杆菌( H pylori) cagA、iceA基因及其不同组合对H pylori感染结局的影响, 探讨西安地区H pylori的优势致病基因型.方法: 用快速尿素酶试验(rapid urease test,RUT)筛选出H pylori阳性胃黏膜标本101例,细菌基因组DNA提取试剂盒提取DNA, 用聚合酶链反应(PCR)扩增尿素酶C( ureC)基因的方法筛选出H pylori阳性标本91例. 经PCR及琼脂糖凝胶电泳对cagA, iceA的基因亚型进行检测, 用χ2检验以及Fisher精确检验分析各基因及其不同组合与疾病的相关性.结果: cagA基因的阳性率为79.1%, iceA的总检出率为75.82%, 其中iceA1为50.5%, iceA2为38.5%, cagA+/ iceA1+的检出率高于其他组,单一基因及其不同组合在各疾病组中分布没有显著差异. iceA与cagA存在相关性. iceA2分别发现有229、334、439、549 bp以及229bp+334 bp的基因片段.结论: cagA+/ iceA1+是西安地区H pylori的优势致病基因型, cagA、iceA1、iceA2各单一基因以及其不同组合与感染的临床结局无关. iceA与cagA基因可能存在协同作用, 该地区iceA2基因有较大的变异性.     

幽门螺杆菌TaqMan MGB探针双重荧光定量PCR检测方法的建立北大核心CSCD

目的建立用于幽门螺杆菌快速定量检测和分型的TaqMan MGB探针双重荧光定量PCR方法。方法采用Primer Premier 5软件分析设计引物和探针,采用双重荧光定量PCR扩增幽门螺杆菌CagA和VacA基因片段,建立循环数与拷贝数关系的标准曲线。检测临床标本中所含幽门螺杆菌的循环数,用该方法对临床胃黏膜标本进行检测并与标准曲线对比,计算所含幽门螺杆菌的拷贝数。结果建立的TaqMan MGB双重荧光定量PCR方法检测幽门螺杆菌质粒的线性范围是10~2~10~8拷贝/μl,CagA和VacA基因标准曲线的相关系数分别是0.977 8和0.990 4。29份临床胃黏膜标本的CagA和VacA基因循环数Ct值分别在29~35和30~35之间,幽门螺杆菌拷贝数分别在1.0×10^(1.39)~1.0×10^(3.87)和1.0×10^(3.06)~1.0×10^(3.91)之间,且临床标本中的幽门螺杆菌均为I型。结论建立的TaqMan MGB双重荧光定量PCR法具有敏感、精确、快速的特点,可用于幽门螺杆菌的快速定量检测与分型鉴定。     

Nested polymerase chain reaction for detection of Helicobacter pylori in gastric biopsy specimens

Sensitivity and specificity are important for tests used to defect Helicobacter pylori infection from gastric biopsy specimens. Molecular methods, such as PCR and nested PCR, are sensitive methods for H. pylori detection. The objective of this study was to evaluate the performance of PCR and nested PCR compared to culture, the rapid urease test (RUT) and histology for the diagnosis of H. pylori in 130 gastric biopsy specimens from symptomatic dyspeptic patients. Sensitivity and specificity with PCR were 91 and 100% and with nested PCR were 95 and 97%, respectively. H. pylori was detected by PCR and nested PCR at levels as low as 125 fg (70 cells) and 25 fg (14 cells), respectively. These results suggest nested PCR is a highly sensitive direct method to detect H. pylori infection from biopsy specimens.     

Helicobacter pylori stool antigen (HpSA) test--a simple, accurate and non-invasive test for detection of Helicobacter pylori infection

BACKGROUND/AIMS: To access the reliability of a newly developed test, the Helicobacter pylori (H. pylori) stool antigen (HpSA) test was used for detection of H. pylori infection. METHODOLOGY: Stool specimens were collected from 33 consecutive patients (19 males and 14 females, age range: 16-73 years, mean: 49 years) who received upper gastrointestinal endoscopic examination for gastrointestinal symptoms. The H. pylori status was evaluated based on six different tests: culture, histology, biopsy urease test, 13C-urea breath test (13C-UBT), serology, and HpSA test. A commercial kit using an enzyme-linked immunosorbent assay examined HpSA in the stool. H. pylori status was defined as positive when the culture was positive or concordance of three of the other four tests (histology, biopsy urease test, 13C-UBT, and serology) was positive. RESULTS: Twenty patients were diagnosed as H. pylori-positive. The HpSA test was positive in 19 patients and negative in 14 patients. The sensitivity and specificity were 95.0% and 100%, respectively. The overall accuracy rate was 96.3%. CONCLUSIONS: The HpSA test is a new, simple, non-invasive method for accurate diagnosis of H. pylori infection.     

聚合酶链反应快速检测胃粘膜幽门螺杆菌

本研究的目的是了解简单的PCR方法诊断幽门螺杆菌感染的价值。选用互补于幽门螺杆菌尿素酶A基因片段的一对引物,建立PCR方法扩增幽门螺杆菌DNA,扩增产物经琼脂糖电泳显示一条411bp区带。用PCR扩增41株HP分离菌均阳性,而空肠弯曲菌等8种肠道细菌均阴性,显示100％特异,系列稀释试验显示PCR能检测0.1pg的HP DNA;126例胃粘膜标本用PCR、尿素酶试验、培养和涂片检查,HP检出率分别为70.6％、56.3％、32.5％和56.3％,这些结果提示简单快速的PCR方法是检测HP的有价值的方法。     

Comparison of three PCR methods for detection of Helicobacter pylori DNA and detection of cagA gene in gastric biopsy specimens

AIM:To comparatively evaluate PCR and other diagnosticmethods (the rapid urease test and/or culture) in order todetermine which of the three PCR methods (ureA,glmMand 26-kDa,SSA gene) was most appropriate in the diagnosisof Helicobacterpylori(Hpylori) infection and also to evaluatethe detection of a putative virulence marker of H pylori,thecage,gene,by PCR in biopsy specimens.METHODS:One hundred and eighty-nine biopsy specimenswere collected from 63 patients (three biopsies each)undergoing upper gastroduodenal endoscopy for variousdyspeptic symptoms.The PCR methods used to detectH pylori DNA directly from biopsies were the glmM,26-kDa,ureA and then cagA was used to compare the culturetechnique and CLO for urease with the culture techniquebeing used as the gold standard.RESULTS:Thirty-five percent of the biopsies were positivefor H pylori DNA using the 3 PCR methods,while 68% ofthese were positive for the cagA gene.Twenty-four percentof the biopsies were negative for H pylori DNA in all PCRmethods screened.The remaining 41% were either positivefor ureA gene only,glmM only,26-kDa only,or ureA glmM,ureA 26-kDa,glmM 26-kDa.Out of the 35% positivebiopsies,41% and 82% were positive by culture and CLOrespectively,while all negative biopsies were also negativeby culture and cagA.Cag A infection was also predominantlyfound in H pylori DNA of the biopsies irrespective of theclinical diagnosis.CONCLUSION:This method is useful for correctly identifyinginfections caused by H pylori and can be easily applied inour laboratory for diagnostic purposes.     

Comparison of three PCR methods for detection of Helicobacter pylori DNA and detection of cagA gene in gastric biopsy specimens

AIM: To comparatively evaluate PCR and other diagnostic methods (the rapid urease test and / or culture) in order to determine which of the three PCR methods (ureA, glmM and 26-kDa, SSA gene) was most appropriate in the diagnosis of Helicobacter pylori (H pylori ) infection and also to evaluate the detection of a putative virulence marker of H pylori, the cagA gene, by PCR in biopsy specimens. METHODS: One hundred and eighty-nine biopsy specimens were collected from 63 patients (three biopsies each) undergoing upper gastroduodenal endoscopy for various dyspeptic symptoms. The PCR methods used to detect H pylori DNA directly from biopsies were the glmM, 26-kDa, ureA and then cagA was used to compare the culture technique and CLO for urease with the culture technique being used as the gold standard. RESULTS: Thirty-five percent of the biopsies were positive for H pylori DNA using the 3 PCR methods, while 68% of these were positive for the cagA gene. Twenty-four percent of the biopsies were negative for H pylori DNA in all PCR methods screened. The remaining 41% were either positive for ureA gene only, glmM only, 26-kDa only, or ureA + glmM, ureA + 26-kDa, glmM + 26-kDa. Out of the 35% positive biopsies, 41% and 82% were positive by culture and CLO respectively, while all negative biopsies were also negative by culture and cagA. Cag A+ infection was also predominantly found in H pylori DNA of the biopsies irrespective of the clinical diagnosis. CONCLUSION: This method is useful for correctly identifying infections caused by H pylori and can be easily applied in our laboratory for diagnostic purposes.     

Significantly elevated Helicobacter pylori density and different genotype distribution in erosions as compared with normal gastric biopsy specimen detected by quantitative real-time PCR

BACKGROUND AND AIM: Determination of the local densities of Helicobacter pylori and its genotypic variations in gastric biopsy specimens by using novel real-time PCR-based methods could support the precise diagnosis and understanding of H. pylori infections. METHODS: Serial dilutions of H. pylori (0.016-16 microg/microl), control, bacterial, and human DNA samples were prepared. Fresh-frozen gastric biopsy specimens were taken from 103 patients, and the DNA was isolated. Quantitative determination of the ureaseA gene using hybridization probes with parallel evaluation of an internal human control gene (beta-globin) was performed by real-time PCR. CagA and VacA s1 genotypic characterizations were also performed. The data were compared with urea breath test (UBT), histology, and serological testing. RESULTS: The presence of H. pylori could be detected by ureaseA-fluorescence energy transfer (53%), UBT (51%), serological testing (48%), and histology (52%) when compared with the gold standard (54%). A significant correlation was found between the quantitative real-time ureaseA/beta-globin ratio-based H. pylori frequency and the UBT results (P<0.01). Significantly increased bacterial density was found in the erosions when compared with the healthy part of the antrum and corpus (P<0.01). Real-time PCR VacA s1 results were in significant correlation (P<0.01) with those of serological tests, but CagA results were not. The genomic profiles (VAC/GAC) were different in 13.7% of the cases, which involved three different locations in the stomach. CONCLUSION: Real-time PCR was the most reliable method for H. pylori diagnosis. Furthermore, quantification and genotyping could also be performed using this technique. The density of H. pylori was significantly increased in macroscopic erosions.     

Karmali和Columbia培养基初次分离幽门螺杆菌效果的比较

目的:比较两种基础培养基对幽门螺杆菌(Hpylorr)感染者的胃黏膜标本初次分离率的差异.方法:将168份,3C呼气试验阳性患者的胃黏膜标本研磨后,等量接种于Karmali和Columbia血琼脂培养基,置于37℃微需氧环境(50mL/LO_2,100ML/L CO_2和850mL/L N_2),分别培养24,48,7...     

Detection of Helicobacter pylori cagA gene by polymerase chain reaction in faecal samples.

OBJECTIVE: The polymerase chain reaction (PCR) has been extensively and successfully used to detect Helicobacter pylori in gastric juice and gastric biopsies. In contrast, the results obtained using faeces as biological samples for PCR are rather conflicting. This may be due to the presence of faecal inhibitory compounds (polysaccharides) which can inhibit the amplification reaction. The aim of this study was to characterize the H. pylori genotype in faecal samples by using specific primers for the cagA gene. To overcome the problem of contamination by polysaccharides, we used a filter-based extraction technique already applied in a previous study. METHODS: Antral and body biopsies were obtained from 30 symptomatic patients undergoing upper endoscopy. PCR was used to detect the presence of H. pylori organisms in faecal samples by using primers selected for the urease gene A. In addition, H. pylori organisms were characterized both in faecal samples and paraffin-embedded biopsies by PCR with specific primers for the cagA gene. RESULTS: All patients showed a positive CLO test (rapid urease test) and evidence of H. pylori by Warthin-Starry stain. PCR detected the urease A gene in the faecal samples of all patients. The cagA gene was detected in the faecal and biopsy samples of 18 subjects (60%). Duodenal ulcer and/or antral erosions were observed in 15 of the 18 cagA-positive patients (83.3%) and in five of the 12 cagA-negative patients (41.7%). Endoscopic features of normal mucosa or gastritis were observed in three cagA-positive patients (16.7%) and in seven cagA-negative patients (56.3%). cagA-positive status was found to be significantly related to the endoscopic features of duodenal ulceration and/or antral erosions. CONCLUSIONS: Our findings prove that faeces are suitable samples for the detection of cagA status. Moreover, they confirm the existence of a significant relationship between cagA-positive status and duodenal ulcer and/or antral erosions.     

Use of different PCR primers and gastric biopsy tissue from CLO test for the detection of Helicobacter pylori

Four different DNA loci were assessed for the detection of H. pylori by PCR on gastric biopsy specimens. PCR, with a primer specific 860 bp DNA fragment, was the most sensitive, with a detection limit of 0.02 pg H. pylori DNA, corresponding to approximately 10 organisms. Nested-PCR of the 860-bp DNA fragment was 10-fold more sensitive than single-step PCR. The sensitivity and specificity of the four PCR methods, in comparison to the results obtained from histology and the urease test, are as follows: 80.7% and 76% for the hpaA gene; 100% and 76% for the 16S rRNA gene; 84.6% and 80.0% for the 860-bp DNA fragment; 61.5% and 84.0% for the ureC (glmM) gene, respectively. The sensitivity of nested-PCR for the 860-bp DNA fragment was 100%. This nested-PCR gave positive results for eight specimens which were negative by conventional methods. PCR can be performed on gastric biopsy specimens obtained from the CLO test.     

Real-time PCR assay for rapid detection of clarithromycin-resistant helicobacter pylori in gastric biopsy specimens

The main cause for failure of Helicobacter pylori eradication therapy is resistance to clarithromycin which is due to point mutations. The use of real-time PCR allows the detection of these mutations directly on biopsy specimens within a few hours. In our routine laboratory, we compared LightCycler PCR to conventional detection and susceptibility testing of H. pylori by culture. PCR showed a positive result for H. pylori in 74 specimens. PCR was confirmed by culture in 69 specimens. In five specimens which were positive by PCR but negative on culture the (13)C urea breath test confirmed the PCR results. Sensitivity and specificity of our LightCycler assay for the detection of H. pylori in biopsy specimens were both 100 %. In 26 out of 68 specimens conventional susceptibility testing yielded resistance to clarithromycin. Corresponding point mutations were found in 24 of these specimens. Compared to culture, PCR gave a false-resistant, respectively, a false sensitive result in one specimen each. In another specimen, culture yielded a resistant strain whereas PCR detected both a resistant mutant and the wild-type strain. From two other specimens clarithromycin-sensitive strains were cultured but both a wild-type strain and a mutant were detected by PCR. Sensitivity and specificity of LightCycler PCR for resistance to clarithromycin were 96.2 % and 97.6 %, respectively. This assay had an accuracy comparable to culture and could be performed within 3 hours, allowing it to be used before the administration of H. pylori eradication therapy.