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。

Association between Helicobacter pylorivirulence and duodenal ulcer disease in patients from Hong Kong in China

Objective A number of putative virulence factors have been postulated to be relevant to the clinical outcome of Helicobacter pylori infection based on strains identified in the western countries. The aim of this study was to investigate the association between genotypes of vacA, cagA and iceA and duodenal ulcer disease in patients from Hong Kong. Methods Seventy two dyspeptic patients with or without duodenal ulcer disease, with proven H.pylori infection, were studied. Gastric biopsy specimens were analyzed by specific polymerase chain reaction and Southern blot to determine the genotypes of these virulence factors. Results Except 6( 8.3 %) cases with evidence of multiple infections, all of the remaining 66 cases had vacA signal sequence s1 type strains. Twenty seven (90%) of the 30 cases with duodenal ulcers were infected with cagA positive strains, compared with 32( 88.9 %) of 36 with non ulcer dyspepsia ( P > 0.05 ). Similarly, vacA middle region sequences were detected with no significant difference in the two groups, 9( 30.0 %) versus 13( 36.1 %) for m1b and 21( 70.0 %) versus 23( 63.9 %) for m2 type. IceA1 subtype was detected in the same frequency in 42 (63.6 %) of the 66 cases. Neither cagA nor vacA and iceA were associated with duodenal ulcer disease. Conclusion No clear differences were found in the distribution of cagA, vacA and iceA genotypes among patients with duodenal ulcer or non ulcer dyspepsia. The association of these virulence genes and duodenal ulcer disease needs reappraisal, particularly under geographic considerations.