Microbiology Department, High Institute of Public Health, Alexandria University, High Institute of Public Health, Egypt.
Ann Clin Microbiol Antimicrob. 2011 Feb 8;10:7. doi: 10.1186/1476-0711-10-7.
Serodiagnosis of typhoid fever by Widal test based on demonstrating the presence of agglutinins (antibodies) in the serum of an infected patient, against the H (flagellar) and O (somatic) antigens of Salmonella enterica serotype Typhi has been associated with many debates. This is why the aim of this study was to: (i) Compare the diagnostic accuracy of four different commercial kits used to perform Widal test (Remel, BioSystems, Dialab and Biotec). (ii) Compare the sensitivity and specificity of both anti-O and anti-H antibodies. (iii) Compare the validity of single versus paired serum samples with a rising titer for the diagnosis of typhoid fever.
Duplicate serum samples were obtained from 150 patients clinically diagnosed as typhoid fever patients. Moreover, single serum samples were obtained from 25 patients with febrile diseases other than typhoid fever. All samples were tested using the four different Widal brands and Salmonella Typhi IgM anti-LPS ELISA.
-The results of Widal tests differed markedly using the four Widal brands in terms of sensitivity and specificity at three cut-off values of 1/80, 1/160 and 1/320. Remel brand gave the highest sensitivities and the lowest specificities and Dialab brand gave the highest specificities and the lowest sensitivities for both anti-O and anti-H antibodies at the three cut-off values.-Four fold rise in the antibodies titer was not demonstrable among clinically diagnosed typhoid fever patients-H agglutinins were less sensitive and less specific than O agglutinins
-Widal test results showed marked discrepancies using different Widal brands. None of the serum samples of the typhoid fever patients showed four fold rise in the antibody titers. Raised O agglutinins were of slightly greater diagnostic value than raised H agglutinins.
Widal test done sequentially using two brands could be of value in typhoid fever diagnosis. Single serum sample could be used for typhoid fever diagnosis relying on anti O titer.
基于血清中抗伤寒沙门氏菌血清型 Typhi 的 H（鞭毛）和 O（体）抗原的凝集素（抗体）的存在来检测伤寒血清的魏氏试验（Widal test），一直存在许多争议。因此，本研究的目的是：（i）比较四种不同商业试剂盒（Remel、BioSystems、Dialab 和 Biotec）用于进行魏氏试验的诊断准确性。（ii）比较抗-O 和抗-H 抗体的敏感性和特异性。（iii）比较单份血清样本与具有上升滴度的配对血清样本对伤寒诊断的有效性。
从 150 例临床诊断为伤寒的患者中获得了重复的血清样本。此外，从 25 例非伤寒发热性疾病患者中获得了单份血清样本。使用四种不同的魏氏品牌和伤寒沙门氏菌 IgM 抗 LPS ELISA 对所有样本进行了检测。
-四种魏氏品牌的魏氏试验结果在三个截断值（1/80、1/160 和 1/320）下，在敏感性和特异性方面差异显著。Remel 品牌的敏感性最高，特异性最低，Dialab 品牌的特异性最高，敏感性最低，适用于两种抗-O 和抗-H 抗体。-在临床诊断的伤寒患者中，无法证明抗体滴度有四倍的增加。H 凝集素的敏感性和特异性均低于 O 凝集素。
-不同魏氏品牌的魏氏试验结果存在明显差异。没有一例伤寒患者的血清样本显示抗体滴度有四倍的增加。升高的 O 凝集素比升高的 H 凝集素具有稍大的诊断价值。
使用两种品牌的魏氏试验连续进行可能对伤寒诊断有价值。依赖于 O 抗体滴度，可以使用单份血清样本进行伤寒诊断。
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