Abstract：
Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of paratuberculosis (PTBC), a chronic infectious granulomatous enteritis of ruminants. The PTBC diagnosis with commercial ELISA has limitations in sensitivity and specificity, and its results depend on the state of progress of the disease. This research aimed to evaluate two different ELISAs: (a) an \"in-house\" ELISA with a sonicated antigen obtained from a MAP I47 strain, and (b) a commercial ELISA. In total, the evaluated sample consisted of 394 bovine serum samples from 12 farms in Argentina with high (5-9%) and low (≤ 0.05%) prevalence of PTBC. The evaluation of the new antigen (2.5 µg/mL) was against a 1:50 dilution of the M. phlei faced sera. The cut-off point, sensitivity, and specificity determinations of both techniques were by ROC curve analysis. The area under the curve for the I47 ELISA was 0.9 (CI 95%, 0.93-0.97). With a cut-off point of 8.8%, the sensitivity was 84.3% and the specificity 96.6%. The agreement between both techniques was 0.7 (CI 95%, 0.6-0.8). These results indicate a high discriminative capacity to differentiate positive and negative bovine sera of MAP infection with the I47 ELISA. This result would represent an advantage to dispense with the imported kit.
摘要：
鸟分枝杆菌亚种。副结核病（MAP）是副结核病（PTBC）的病因，反刍动物的慢性传染性肉芽肿性肠炎。商业ELISA的PTBC诊断在灵敏度和特异性方面存在局限性,其结果取决于疾病的进展状态。这项研究旨在评估两种不同的ELISA：（a）使用从MAPI47菌株获得的超声处理抗原的“内部”ELISA，和(b)商业ELISA。总的来说,评估样本包括来自阿根廷12个农场的394例牛血清样本,PTBC患病率高(5-9%)和低(≤0.05%).新抗原(2.5μg/mL)的评价是针对1:50稀释的草分枝杆菌面对的血清。截止点,灵敏度,两种技术的特异性测定均通过ROC曲线分析。I47ELISA的曲线下面积为0.9（CI95％，0.93-0.97）。截止点为8.8%,敏感性为84.3%,特异性为96.6%.两种技术之间的一致性为0.7(CI95%，0.6-0.8）。这些结果表明用I47ELISA区分MAP感染的阳性和阴性牛血清的高辨别能力。该结果将代表免除进口套件的优点。
