Pan Z J, van der Hulst R W, Tytgat G N, Dankert J, van der Ende A
Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, The Netherlands.
Am J Gastroenterol. 1999 Jun;94(6):1517-21. doi: 10.1111/j.1572-0241.1999.01136.x.
The vacuolating cytotoxin of Helicobacter pylori (H. pylori) is encoded by vacA, of which allelic variation has been described. In the U.S., H. pylori strains with the signal sequence allele s1a are associated with enhanced gastric inflammation and with peptic ulcer disease (PUD). The m1 middle region allele is linked with more severe gastric epithelial damage. However, the distribution of H. pylori genotypes and the association with disease may be different in other geographical areas. The aim of this study was to establish whether vacA types among H. pylori isolates from Dutch patients are associated with disease.
The cytotoxin activity of the H. pylori isolates from 34 PUD patients and 46 patients with functional dyspepsia (FD) was assessed by an in vitro assay using HeLa cells as indicator cells. The vacA types and cagA status of the isolates were assessed by polymerase chain reaction (PCR).
vacA s1-type H. pylori displayed cytotoxin activity more frequently than s2 vacA-type H. pylori (p = 0.003). This difference was not significant when only cagA+ H. pylori were considered. H. pylori isolates with the m1 vacA type exhibited a higher cytotoxin activity, independent of cagA (p = 0.006). Ninety-four percent (32/34) of the PUD patients and 74% (34/46) of the FD patients were infected with s1 vacA-type H. pylori (p = 0.04). When only cagA+ H. pylori were considered, s1 vacA type was not associated with disease. In addition, neither the s1a nor s1b subtypes correlated with disease.
An association between vacA subtypes and disease could not be established in this patient population, due to the strong linkage between vacA s1 type and cagA.
幽门螺杆菌（H. pylori）的空泡毒素由vacA编码，其存在等位基因变异。在美国，具有信号序列等位基因s1a的幽门螺杆菌菌株与胃炎症增强及消化性溃疡病（PUD）相关。m1中间区域等位基因与更严重的胃上皮损伤有关。然而，幽门螺杆菌基因型的分布及其与疾病的关联在其他地理区域可能有所不同。本研究的目的是确定荷兰患者分离出的幽门螺杆菌中vacA类型是否与疾病相关。
使用HeLa细胞作为指示细胞，通过体外试验评估了34例PUD患者和46例功能性消化不良（FD）患者分离出的幽门螺杆菌的细胞毒素活性。通过聚合酶链反应（PCR）评估分离株的vacA类型和cagA状态。
vacA s1型幽门螺杆菌比s2 vacA型幽门螺杆菌更频繁地表现出细胞毒素活性（p = 0.003）。仅考虑cagA阳性的幽门螺杆菌时，这种差异不显著。具有m1 vacA类型的幽门螺杆菌分离株表现出更高的细胞毒素活性，与cagA无关（p = 0.006）。94%（32/34）的PUD患者和74%（34/46）的FD患者感染了s1 vacA型幽门螺杆菌（p = 0.04）。仅考虑cagA阳性的幽门螺杆菌时，s1 vacA型与疾病无关。此外，s1a和s1b亚型均与疾病无关。
由于vacA s1型与cagA之间的强连锁关系，在该患者群体中无法确定vacA亚型与疾病之间的关联。
