广州地区患儿感染幽门螺杆菌vacA、cagA及iceA基因研究

目的探讨广州地区患儿感染幽门螺杆菌（Hp）的vacA、cagA、iceA的基因亚型和优势基因亚型。方法105例胃、十二指肠疾病患儿的胃窦处取3块胃黏膜,分别进行快速尿素酶反应、病理检查和聚合酶链反应（PCR）。抽提胃黏膜基因组DNA,用11对引物,检测HpureA、vacA、cagA和ieeA基因,分析HpvacA、cagA、iceA基因亚型。结果快速尿素酶反应、病理检查和PCR三者均阳性的标本52例,其中感染Hp vacA s1as1c／m2、s1as1c／m1T亚型菌株的阳性率分别是82．7％（43／52）、9．6％（5／52）,m区不能分型占7．7％（4／52）,Hp vacA s1as1c／m2与其他基因亚型相比较,差异有统计学意义。Hp vacA s1a和s1c亚型总是同时检出,未发现Hp vacA s1b、s2、m1亚型。HpcagA^＋菌株检出率是90．4％（47／52）,cagA^-菌株检出率9、6％（5／52）,二者比较,差异有统计学意义。Hp iceA1亚型菌株单独检出率78．8％（41／52）,Hp iceA2亚型菌株单独检出率是1．9％（1／52）,Hpi ceA1和ieeA2亚型均阳性是3．8％（2／52）,iceA1和iceA2亚型均阴性的比率是15．4％（8／52）,Hp iceA1亚型阳性率与其他基因亚型相比较,差异有统计学意义。结论Hp的Hp vacA s1as1c／m^2、cagA^＋、iceA1亚型是广州地区患儿感染的Hp的优势基因亚型,Hp vacA s1as1c／m^2、cagA。和iceA1基因组合是广州地区患儿感染的Hp的优势基因亚型组合。

Genotypic study on the Helicobacter pylori vacA, cagA and iceA genes in the infected children in Guangzhou area

OBJECTIVE: To investigative vacA, cagA and iceA genes dominant genotypes of Helicobacter pylori (Hp) isolated from children suffering from gastric and duodenal diseases in Guangzhou area. METHODS: Totally 105 children who underwent gastroscopy in Guangzhou Children's Hospital were enrolled into this study. From each patient, 3 biopsy specimens from the gastric antrum were taken, one was used for rapid urease test, one for histological examination, and one for polymerase chain reaction (PCR) for detecting ureA, vacA, cagA, and iceA genes. DNA was prepared directly from the biopsy specimens from the gastric antrum using a QIAamp DNA mini kit (Qiagen, Germany) according to the manufacturer's instructions. Then 11 primers were used for detecting the genotypes including ureas, (s1, s1a, s1b, s1c, s2) and m (m1, m1T, m2) region of vacA, cagA and iceA (iceA1 and iceA2) genotypes in the 105 children. The distribution of the genotypes of Hp was analyzed. RESULT: Among the 105 children, only 52 children were positive by the three methods, among these 52 children, 26 were boys and 26 girls. Hp vacA s1as1c/m2 was detected in 43 out of 52 children (82.7%), s1as1c/m1T in 9.6% (5/52), m region that could not betyped was 7.7% (4/52). No strains presented genotypes vacA s1b, s2, m1. The comparison of the positive ratio of vacA s1as1 c/m2 detected in the children infected with Hp and that of the other combination of signal region and middle region was statistically significantly different (P < 0.01). With regard to cagA gene, cagA(+) gene and cagA(-) gene were found in 90.4% (47/52) and 9.6% (5/52) of the children, respectively. The cagA(+) gene was more frequent in the children infected with Hp. Single iceA1 was detected in 78.8% (41/52) children, and single iceA2 was detected to be 1.9% (1/52), multiple strains infection of iceA1 and iceA2 were detected in 3.8% (2/52) children, iceA1 and iceA2 were not detected in 15.4% (8/52), the comparison of the positive ratio of iceA1 detected in the children infected with Hp and that of the other genotypes was statistically significantly different (P < 0.01). CONCLUSION: The s1as1c/m2, cagA and iceA1 were the dominant genotypes of Hp in the children in Guangzhou area and s1as1c/m2, cagA and iceA1 were the dominant genotypes combination of Hp in the children in this area.