[Study and preparation of Vi-PHA reagent and its application for detection of Salmonella typhi carriers].
Purified S. typhi Vi antigen is sensitized with equal volume of tannic acid treated formalational sheep erythrocytes (SRBC) at a final concentration of 1 microgram/ml. The Vi-passive hemagglutination assay (Vi-PHA) diagnostic reagent is developed to detect Vi antibodies to S. typhi for the detection of chronic carriers after typhoid fever and the screening S. typhi healthy carriers from food-handlers, which is characterized with high sensitivity, strong specificity and good stability. This Vi-PHA reagent is able to detect 1.16 micrograms/ml of Vi antibodies and doesn't make any cross reaction with healthy sera. For the sera of other diseases, the cross rate is only 0.84%. Using this reagent, 19 positive sera (6.93%) are detected from 274 convalescent sera from typhoid fever, 14 convalescents of which are stool-culture S. typhi positive, that persists a positive rate of 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 in basic unit.
Bao
X
X
Sanitary and Epidemic Center of Zhejiang Province, Hangzhou.
Qiu
J
J
Yang
N
N
Mei
L
L
Chen
X
X
D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology*; D002353:Carrier State / Q000175:diagnosis*; D006386:Hemagglutination Tests / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D011135:Polysaccharides, Bacterial; D012485:Salmonella typhi / Q000276:immunology / Q000302:isolation & purification*; D014435:Typhoid Fever / Q000175:diagnosis*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007202:Indicators and Reagents; D011135:Polysaccharides, Bacterial