通过聚合酶链反应检测粪便样本中的幽门螺杆菌cagA基因。

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

作者信息

Russo F, Notarnicola M, Di Matteo G, Leoci C, Caruso M L, Pirrelli M, Caradonna M, Morandi L, Di Leo A

机构信息

Laboratory of Biochemistry, IRCCS Scientific Institute for Digestive Diseases S. de Bellis, Castellana G., Bari, Italy.

出版信息

Eur J Gastroenterol Hepatol. 1999 Mar;11(3):251-6. doi: 10.1097/00042737-199903000-00008.

DOI:10.1097/00042737-199903000-00008

PMID:10333197

Abstract

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.

摘要

目的

聚合酶链反应（PCR）已被广泛且成功地用于检测胃液和胃活检组织中的幽门螺杆菌。相比之下，将粪便作为PCR生物样本所获得的结果却相当矛盾。这可能是由于粪便中存在抑制性化合物（多糖），其可抑制扩增反应。本研究的目的是通过使用针对cagA基因的特异性引物来鉴定粪便样本中的幽门螺杆菌基因型。为克服多糖污染问题，我们采用了先前一项研究中已应用的基于滤膜的提取技术。

方法

从30例接受上消化道内镜检查的有症状患者获取胃窦和胃体活检组织。通过使用针对脲酶基因A选择的引物，采用PCR检测粪便样本中幽门螺杆菌的存在情况。此外，通过使用针对cagA基因的特异性引物，采用PCR对粪便样本和石蜡包埋的活检组织中的幽门螺杆菌进行鉴定。

结果

所有患者的CLO试验（快速脲酶试验）均呈阳性，且经Warthin-Starry染色显示有幽门螺杆菌存在。PCR在所有患者的粪便样本中均检测到脲酶A基因。18名受试者（60%）的粪便和活检样本中检测到cagA基因。18例cagA阳性患者中有15例（83.3%）观察到十二指肠溃疡和/或胃窦糜烂，12例cagA阴性患者中有5例（41.7%）观察到上述情况。3例cagA阳性患者（16.7%）和7例cagA阴性患者（56.3%）观察到正常黏膜或胃炎的内镜特征。发现cagA阳性状态与十二指肠溃疡和/或胃窦糜烂的内镜特征显著相关。