Sozzi Michele, Tomasini Maria Luisa, Vindigni Carla, Zanussi Stefania, Tedeschi Rosamaria, Basaglia Giancarlo, Figura Natale, De Paoli Paolo
Unit of Gastroenterology and Digestive Endoscopy, General Hospital, Trieste, Italy.
J Lab Clin Med. 2005 Nov;146(5):262-70. doi: 10.1016/j.lab.2005.06.010.
Helicobacter pylori infecting strains may include colony subtypes with different cytotoxin-associated gene (cag) genotypes. We sought to determine whether the cag heterogeneity of infecting strains is related to the clinical outcome of infection. Gastric biopsies for culture and histologic study were taken from 19 patients infected with cagA-positive strains (6 with duodenal ulcer, 8 with atrophic gastritis, and 5 with nonatrophic gastritis). For each biopsy, DNA was extracted from 10 single colonies and from a sweep of colonies. Polymerase chain reaction (PCR) for cagA and cagE (both located in the right half of cag) and virB11 (located in the left half of cag) was performed. Random amplified polymorphic DNA PCR (RAPD-PCR) and sequencing of glmM PCR product were performed to verify strain identity of colonies with different cag genotypes. In all patients, PCR from sweeps were positive for cagA, showing that all specimens contained cagA-positive H. pylori subtypes. In 11 patients, PCR products from all colonies were positive for cagA, cagE, and virB11, but in 8 patients, PCR products from varying numbers of colonies were negative for 1 or more cag genes. RAPD-PCR and sequencing of glmM PCR product confirmed the strain identities of colonies with different cag genotypes. We detected cag deletions in 6 of 8, 2 of 5, and 0 of 6 patients with atrophic gastritis, nonatrophic gastritis, and duodenal ulcer, respectively (P = .02). In conclusion, changes in cag genotype in single colony isolates from subjects infected with cagA-positive H. pylori strains are more common in atrophic than in nonatrophic gastritis or duodenal ulcer. These findings are consistent with host-induced (acid secretion?) adaptive changes in cag genotype during infection.
幽门螺杆菌感染菌株可能包括具有不同细胞毒素相关基因（cag）基因型的菌落亚型。我们试图确定感染菌株的cag异质性是否与感染的临床结果相关。对19例感染cagA阳性菌株的患者进行胃活检以进行培养和组织学研究（6例十二指肠溃疡患者、8例萎缩性胃炎患者和5例非萎缩性胃炎患者）。对于每例活检标本，从10个单个菌落和一片菌落中提取DNA。进行cagA和cagE（均位于cag右半部分）以及virB11（位于cag左半部分）的聚合酶链反应（PCR）。进行随机扩增多态性DNA PCR（RAPD-PCR）和glmM PCR产物测序以验证具有不同cag基因型的菌落的菌株身份。在所有患者中，来自一片菌落的PCR检测cagA呈阳性，表明所有标本均含有cagA阳性的幽门螺杆菌亚型。在11例患者中，所有菌落的PCR产物cagA、cagE和virB11均为阳性，但在8例患者中，不同数量菌落的PCR产物对1个或更多cag基因呈阴性。RAPD-PCR和glmM PCR产物测序证实了具有不同cag基因型的菌落的菌株身份。我们分别在8例萎缩性胃炎患者中的6例、5例非萎缩性胃炎患者中的2例和6例十二指肠溃疡患者中的0例中检测到cag缺失（P = 0.02）。总之，感染cagA阳性幽门螺杆菌菌株的受试者单个菌落分离株中cag基因型的变化在萎缩性胃炎中比在非萎缩性胃炎或十二指肠溃疡中更常见。这些发现与感染期间宿主诱导的（酸分泌？）cag基因型适应性变化一致。
