Centre for Diagnostics, DTU Health Technology, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark.
National Veterinary Institute, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark.
BMC Vet Res. 2022 Jul 5;18(1):259. doi: 10.1186/s12917-022-03362-w.
Since 1995, a surveillance program for Salmonella has been applied in the Danish pig industry in order to reduce cases of human salmonellosis. The objective of this study was to develop a bead-based Multiplexed Fluorometric ImmunoAssay (MFIA) as an improved serological surveillance method compared to the Salmonella mix ELISA, which has been the national reference immunoassay in the Danish Salmonella surveillance program for about 20 years.
An MFIA for detection of antibodies to Salmonella serogroup B and C was developed and optimized with regard to coupling of beads with Salmonella lipopolysaccharide antigens and establishing suitable assay conditions. The Salmonella MFIA was validated by testing sera from experimentally infected pigs as well as field sera from non-infected and infected pig herds, and by comparing to results from the Salmonella mix ELISA, which was run in parallel. Sensitivity and specificity was evaluated using receiver operating curve analysis showing an area under curve for the serogroup B and C MFIA of 0.984 and 0.998, respectively. The Salmonella MFIA was shown to detect more antibody-positive samples in seropositive herds compared to the Salmonella mix ELISA, and Bayesian statistics confirmed that the MFIA had a considerably higher sensitivity (94.5%) compared to the mix ELISA (75.1%). The assay specificity was slightly lower for the Salmonella MFIA (96.8%) compared to Salmonella mix ELISA (99.5%). Coupled beads were stable for at least 1 year at 4˚C, and MFIA reproducibility and repeatability of the Salmonella MFIA were acceptable. Results from proficiency tests also indicated that the Salmonella MFIA was more sensitive than the Salmonella mix ELISA and that they had similar specificity.
A bead-based MFIA for simultaneous detection of porcine serum antibodies to Salmonella enterica serogroup B and C was developed and implemented in the Danish porcine serological Salmonella surveillance program in 2018. The Salmonella MFIA can distinguish, as opposed to the Salmonella mix ELISA, between antibodies to serogroup B and C and the MFIA shows considerably better sensitivity.
自 1995 年以来，丹麦养猪业一直在实施沙门氏菌监测计划，以减少人类沙门氏菌病的病例。本研究的目的是开发一种基于珠子的多重荧光免疫分析（MFIA），作为一种比沙门氏菌混合 ELISA 更优的血清学监测方法，这种 ELISA 作为丹麦沙门氏菌监测计划的国家参考免疫分析已经有大约 20 年的历史。
开发并优化了一种用于检测沙门氏菌血清群 B 和 C 抗体的 MFIA，方法是用沙门氏菌脂多糖抗原偶联珠子，并建立合适的测定条件。通过对实验感染猪的血清以及非感染和感染猪群的田间血清进行检测，并与平行运行的沙门氏菌混合 ELISA 进行比较，对沙门氏菌 MFIA 进行了验证。使用接收者操作曲线分析评估了灵敏度和特异性，结果表明血清群 B 和 C MFIA 的曲线下面积分别为 0.984 和 0.998。与沙门氏菌混合 ELISA 相比，MFIA 显示在血清阳性群中检测到更多的抗体阳性样本，贝叶斯统计证实 MFIA 的灵敏度（94.5%）明显高于混合 ELISA（75.1%）。与沙门氏菌混合 ELISA（99.5%）相比，沙门氏菌 MFIA 的特异性略低（96.8%）。偶联珠子在 4°C 下至少稳定 1 年，MFIA 的重复性和可重复性均可接受。能力验证结果也表明，沙门氏菌 MFIA 比沙门氏菌混合 ELISA 更敏感，并且它们具有相似的特异性。
开发了一种基于珠子的 MFIA，用于同时检测猪血清中对肠炎沙门氏菌血清群 B 和 C 的抗体，并于 2018 年在丹麦猪血清沙门氏菌监测计划中实施。与沙门氏菌混合 ELISA 不同，MFIA 可以区分血清群 B 和 C 的抗体，并且 MFIA 的灵敏度明显更高。
