聚合酶链反应检测Vi抗原在伤寒早期诊断中的应用

Application of nested PCR for detection of the Vi antigen gene of Salmonella typhi in earlier diagnosis of typhi fever

为选择更为敏感、特异的伤寒早期诊断方法,从伤寒沙门菌表达 Vi 抗原的特异结构基因 ViaB 区域选择二对引物,建立了套式-聚合酶链反应(nested-PCR)。检测伤寒早期标本36份,结果血培养阳性25份(69%),肥达反应阳性17份(47.2%),PCR 阳性29份(80.6%);25份血培养阳性标本,PCR 均为阳性,并从血培养阴性标本中检出 Vi-DNA 阳性4份。研究表明,应用 nest-ed-PCR 检测 Vi-DNA,可提高伤寒病的早期诊断水平。

In order to select more specific and sensitive method for diagnosis of typhi fever a nested- PCR assay for the detection of Salmonella typhi was developed by using two sets of primers based on the ViaB region of Vi antigen gene.Among 36 blood samples from patients with typhoid fever in early phase,25(69%) showed positive for S.typhi by blood culture,17 (47.2%) showed positive by Widal' s reaction and 29(80.6%) were positive by nested-PCR.All 25 cuhure-positive blood samples showed positive by nested-PCR.Among those culture-negative samples,4 were PCR positive.The results sug- gest that nested-PCR for detection of Vi antigen gene in clinical samples is suitable for the earlier diagno- sis of typhoid fever.