Simple and accurate PCR-based system for typing vacuolating cytotoxin alleles of Helicobacter pylori
Simple and accurate PCR-based system for typing vacuolating cytotoxin alleles of Helicobacter pylori
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DOI：
10.1128/jcm.37.9.2979-2982.1999
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发表时间：
1999-09-01
影响因子：
9.4
通讯作者：
Blaser, MJ
中科院分区：
文献类型：
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作者：
Atherton, JC;Cover, TL;Blaser, MJ
幽门螺杆菌空泡毒素基因(VacA)的等位基因在不同菌株之间存在差异，特别是在编码信号序列的区域(可能是s1或s2型)和中部区域(可能是m1或m2型)。使用美国开发的基于PCR的分型系统，我们发现36株来自亚洲和南美洲的菌株均为VacA信号序列S1型，3株为MI型，11株为M2型，但22株不能进行VacA中区的分型。所有菌株都具有cagA(细胞毒素相关基因A)，这是另一个毒力标志。VacA核苷酸序列分析表明，中区分型失败是由于引物退火点的碱基替换所致。使用新的序列数据，我们开发了两个新的基于PCR的VacA中区分型系统，这两个系统都正确地分型了之前由旧系统分型的41株美国菌株，并成功地分型了所有36株非美国菌株。所有以前不能分型的菌株都是Vaca mi，除了一个m1/m2杂交菌株。综上所述，我们描述并验证了一种简单的基于PCR的幽门螺杆菌空泡毒素(VacA)等位基因分型系统，并表明该系统正确地识别了来自亚洲和北美和南美洲的77株VacA的信号型和中区类型。
Alleles of the vacuolating cytotoxin gene (vacA) of Helicobacter pylori vary between strains, particularly in the region encoding the signal sequence (which may be type s1 or s2) and the midregion (which may be type mi or m2). Using a PCR-based typing system developed in the United States, we showed that 36 strains from Asia and South America were all vacA signal sequence type s1; 3 were midregion type mi and 11 were m2, but 22 could not be typed for the vacA midregion. All strains possessed cagA (cytotoxin-associated gene A), another virulence marker. vacA nucleotide sequence analysis showed that midregion typing failure was due to base substitutions at the primer annealing sites. Using the new sequence data, we developed two new PCR-based vacA midregion typing systems, both of which correctly typed 41 U.S. strains previously typed by the old system and successfully typed all 36 of the non-U.S. strains. All previously untypeable strains were vacA mi, other than one m1/m2 hybrid. In summary, we describe and validate a simple PCR-based system for typing vacuolating cytotoxin (vacA) alleles of H. pylori and show that this system correctly identifies the signal and midregion types of vacA in 77 strains from Asia and North and South America.