Vi-PHA试剂的研制及其在检测伤寒带菌者中的应用

STUDY AND PREPARATION OF Vi-PHA REAGENT AND ITS APPLICATION FOR DETECTION OF SALMONELLA TYPHI CARRIERS

用纯化伤寒沙门氏菌的 Vi 抗原,以1μg/ml 量致敏鞣化醛化绵羊红细胞,研制成 Vi-PHA 试剂,用于伤寒病后慢性带菌者的检出及食品从业人员伤寒健康带菌者的筛选。具有敏感性高、特异性强和稳定性好等特点。本试剂能检出1.16μg/ml Vi-抗体。对健康人群血清无交叉,而与非伤寒病种患者血清仅有0.84%交叉反应。用于检测274例伤寒病后3个月以上和1年以内康复者血清,阳性19例,占6.93%。其中14例粪便培养出伤寒沙门氏菌,占 Vi-PHA 总阳性率的73.68%。106例疫区食品从业人员 Vi-PHA 阳性3例,其中1例培养出伤寒沙门氏菌。255例 Vi-PHA≤1∶20的伤寒病后康复者,无1例粪检阳性。结果表明,伤寒康复者血清中 Vi 抗体与其体内带菌具有较高的特异性和相关性。此外,本试剂所采用的方法操作简便,时间快速,结果判断清晰,易在基层推广。

Purified S.typhi Vi antigen is sensitized with equal volume of tannic acid treated formala-tional sheep erythrocytes(SRBC)at a final concentration of 1μg/ml.The Vi-passive hemagglu-tination assay(Vi-PHA)diagnostic reagent is developed to detect Vi antibodies to S.typhi forthe detection of chronic carriers after typhoid fever and the screening S.typhi healthy carriersfrom food-handlers,which is characterized with high sensitivity,strong specificity and goodstability.This Vi-PHA reagent is able to detect 1.16μg/ml of Vi antibodies and doesn't make anycross reaction with healthy sera.For the sera of other diseases,the cross rate is only 0.84%.Us-ing this reagent,19 positive sera(6.93%)are detected from 274 convalescent sera from typhoidfever,14 convalescents of which are stool-culture S.typhi positive,that persists a positive rateof 73.68%;3 positive sera are detected from 106 foodhandlers,one of which is stool-culture S.typhi positive.Therefore,the reagent is simple,convenient,rapid and easy to be applicated inbasic unit.