Laboratorio de Bacteriología, Producción Animal, Instituto Nacional de Tecnología Agropecuaria INTA, Balcarce, Buenos Aires, CC 276, Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Buenos Aires, Argentina.
Vet Res Commun. 2024 Aug;48(4):2645-2650. doi: 10.1007/s11259-024-10363-7. Epub 2024 Apr 5.
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.
分支杆菌 avium subsp. 副结核分枝杆菌（MAP）是副结核病（PTBC）的病原体，是反刍动物的一种慢性传染性肉芽肿性肠炎。商业 ELISA 在 PTBC 诊断中的灵敏度和特异性存在局限性，其结果取决于疾病的进展状态。本研究旨在评估两种不同的 ELISA：（a）使用来自 MAP I47 株的超声抗原的“内部” ELISA，和（b）商业 ELISA。总共有 394 份来自阿根廷 12 个农场的牛血清样本，这些农场的 PTBC 患病率较高（5-9%）和较低（≤0.05%）。对新抗原（2.5 µg/mL）的评估是针对 M. phlei 血清的 1:50 稀释液。两种技术的截断值、灵敏度和特异性的确定是通过 ROC 曲线分析进行的。I47 ELISA 的曲线下面积为 0.9（95%CI，0.93-0.97）。截断值为 8.8%时，灵敏度为 84.3%，特异性为 96.6%。两种技术之间的一致性为 0.7（95%CI，0.6-0.8）。这些结果表明，I47 ELISA 具有较高的区分能力，可区分 MAP 感染的阳性和阴性牛血清。这一结果将代表一种优势，可以不使用进口试剂盒。
