Ashour A A, Collares G B, Mendes E N, de Gusmão V R, Queiroz D M, Magalhães P P, de Carvalho A S, de Oliveira C A, Nogueira A M, Rocha G A, Rocha A M
Laboratory of Molecular Biology, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil, 30130-100.
J Clin Microbiol. 2001 May;39(5):1746-50. doi: 10.1128/JCM.39.5.1746-1750.2001.
Data concerning the geographic distribution of iceA alleles are scarce, and information on the association of the gene with the disease is rare and still controversial. Furthermore, no such study has been developed in Brazil, where duodenal ulcer and gastric adenocarcinoma are very common. We investigated, by PCR, the frequency of iceA alleles and cagA status in Helicobacter pylori strains isolated from 142 patients (62 children and 80 adults; 66 female; mean age, 30.0 years; age range, 3 to 78 years) with gastritis, duodenal ulcer, or gastric adenocarcinoma. iceA was identified in bacterium samples obtained from all patients. Eleven (7.7%) of them were infected with multiple strains. Among the patients with nonmixed infection, iceA2 allele was detected in 118 (90.1%). iceA2 allele was associated with ulcer (P = 0.02) and with carcinoma (P = 0.001). iceA2 amplicons of 229, 334, or 549 bp were detected, but none of them was associated with the patient's disorder. iceA2 strains were more frequent in patients older than 7 years (P = 0.001). The gene was also more frequent in strains obtained from males (P = 0.02). cagA was more common in strains obtained from carcinoma (P = 0.0008) and ulcer patients (P < 0.006). cagA-positive strains were more frequent in children older than 7 years (P < 0.003). No association between cagA status and sex was found (P = 0.28). In conclusion, we think iceA should not be used as a reliable marker for predicting the clinical outcome of H. pylori infection.
关于iceA等位基因地理分布的数据稀少，且该基因与疾病关联的信息罕见且仍存在争议。此外，在十二指肠溃疡和胃腺癌非常常见的巴西尚未开展此类研究。我们通过聚合酶链反应（PCR）调查了从142例患有胃炎、十二指肠溃疡或胃腺癌的患者（62名儿童和80名成人；66名女性；平均年龄30.0岁；年龄范围3至78岁）中分离出的幽门螺杆菌菌株中iceA等位基因的频率和cagA状态。在所有患者的细菌样本中均检测到iceA。其中11例（7.7%）感染了多种菌株。在非混合感染的患者中，检测到118例（90.1%）携带iceA2等位基因。iceA2等位基因与溃疡（P = 0.02）和癌症（P = 0.001）相关。检测到229、334或549 bp的iceA2扩增子，但它们均与患者的疾病无关。iceA2菌株在7岁以上患者中更为常见（P = 0.001）。该基因在从男性分离出的菌株中也更为常见（P = 0.02）。cagA在从癌症患者（P = 0.0008）和溃疡患者（P < 0.006）分离出的菌株中更为常见。cagA阳性菌株在7岁以上儿童中更为常见（P < 0.003）。未发现cagA状态与性别之间存在关联（P = 0.28）。总之，我们认为iceA不应作为预测幽门螺杆菌感染临床结果的可靠标志物。
