评估三种酶联免疫吸附测定法检测牛群牛奶中抗沙门氏菌抗体的特异性。

Evaluation of the specificity of three enzyme-linked immunosorbent assays for detection of antibodies against Salmonella in bovine bulk milk.

机构信息

Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, Uppsala SE-751 89, Sweden.

出版信息

Acta Vet Scand. 2013 Jan 30;55(1):5. doi: 10.1186/1751-0147-55-5.

DOI:10.1186/1751-0147-55-5

PMID:23360615

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC3639889/

Abstract

BACKGROUND

The Swedish Salmonella control program has been running for decades and has resulted in a low prevalence of Salmonella in Swedish food producing animals. Routine bacteriology is used to detect Salmonella, however, bacteriology is time consuming, costly and has a low sensitivity. Different enzyme-linked immunosorbent assays (ELISAs) have been developed for detection of antibodies against Salmonella Dublin and S. Typhimurium in bovine bulk milk, individual milk samples as well as in sera. Screening bulk milk for antibodies against Salmonella spp. could improve the cost-effectiveness of the surveillance in Swedish dairy cattle, but as characteristics of tests may vary in different populations, tests should always be evaluated in the specific population where they will be used. Hence, the aim of this study was to evaluate the specificities of three bovine ELISAs when used to analyse bulk milk samples from Swedish dairy cattle. A second aim was to compare the performance of the two Dublin ELISAs tested.

METHODS

Bulk milk samples for analysis were randomly selected from samples collected within the Swedish bulk milk sampling scheme and analyzed with the three ELISAs; a Danish in-house Dublin ELISA, PrioCHECK(®) Salmonella Ab bovine Dublin ELISA and PrioCHECK(®) Salmonella Ab bovine ELISA (hereafter named mixed ELISA). The specificities of the ELISAs were calculated assuming a disease-free status in Sweden i.e. that all test positive samples were assumed to be false positive results. This assumption can be used when a disease is known to be infrequent.

RESULTS

The calculated specificities of the two Dublin ELISAs and the mixed ELISA, when using the producer's recommended cut-off value of the corrected optic-density percent (ODC%) were 99.4% (95% Confidence Interval (CI): 98.8% -99.8%), 99.4% (95% CI: 98.8% -99.8%) and 97.9% (95% CI: 96.8% -98.7%), respectively. The correlation between the ODC% values of the two Dublin ELISAs was 0.83.

CONCLUSIONS

We conclude that the evaluated ELISAs have sufficiently high specificities to be used as supplement to bacteriological examinations in the Swedish Salmonella control program in cattle as well as a primary screening test in routine surveillance for S. Dublin.

摘要

背景

瑞典的沙门氏菌控制计划已经实施了几十年，因此在瑞典的食品生产动物中，沙门氏菌的流行率较低。常规细菌学用于检测沙门氏菌，但细菌学既费时、昂贵，而且灵敏度低。已经开发了不同的酶联免疫吸附测定（ELISA）来检测牛群的巴氏杀菌奶、个体奶样和血清中抗都柏林沙门氏菌和鼠伤寒沙门氏菌的抗体。对巴氏杀菌奶进行沙门氏菌 spp.抗体筛查可提高瑞典奶牛监测的成本效益，但由于不同人群的测试特性可能存在差异，因此应在将在特定人群中使用的测试在特定人群中进行评估。因此，本研究的目的是评估三种牛 ELISA 在分析瑞典奶牛巴氏杀菌奶样本时的特异性。第二个目的是比较两种测试的都柏林 ELISA 的性能。

方法

用于分析的巴氏杀菌奶样本是从瑞典巴氏杀菌奶抽样计划中收集的样本中随机选择的，并使用三种 ELISA 进行分析；丹麦内部的都柏林 ELISA、PrioCHECK(®) 沙门氏菌 Ab 牛都柏林 ELISA 和 PrioCHECK(®) 沙门氏菌 Ab 牛 ELISA（以下简称混合 ELISA）。ELISA 的特异性是在瑞典假设无病状态下计算的，即所有检测阳性的样本都假定为假阳性结果。当已知疾病很少见时，可以使用这种假设。

结果

当使用制造商推荐的校正光密度百分比（ODC%）截断值时，两种都柏林 ELISA 和混合 ELISA 的计算特异性分别为 99.4%（95%置信区间（CI）：98.8% -99.8%）、99.4%（95% CI：98.8% -99.8%）和 97.9%（95% CI：96.8% -98.7%）。两种都柏林 ELISA 的 ODC%值之间的相关性为 0.83。