Blanco-Vázquez Cristina, Alonso-Hearn Marta, Iglesias Natalia, Vázquez Patricia, Juste Ramón A, Garrido Joseba M, Balseiro Ana, Canive María, Amado Javier, Queipo Manuel A, Iglesias Tania, Casais Rosa
Centro de Biotecnología Animal, Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Deva, Spain.
Department of Animal Health, NEIKER-Basque Institute for Agricultural Research and Development, Basque Research and Technology Alliance (BRTA), Derio, Spain.
Front Vet Sci. 2022 Mar 10;9:816135. doi: 10.3389/fvets.2022.816135. eCollection 2022.
Bovine paratuberculosis (PTB) is a chronic enteritis caused by subspecies (Map) that causes a heavy economic impact worldwide. Map infected animals can remain asymptomatic for years while transmitting the mycobacteria to other members of the herd. Therefore, accurate detection of subclinically infected animals is crucial for disease control. In a previous RNA-Seq study, we identified several mRNAs that were overexpressed in whole blood of cows with different PTB-associated histological lesions compared with control animals without detected lesions. The proteins encoded by two of these mRNAs, ATP binding cassette subfamily A member 13 (ABCA13) and Matrix Metallopeptidase 8 (MMP8) were significantly overexpressed in whole blood of animals with focal histological lesions, the most frequent pathological form in the subclinical stages of the disease. In the current study, the potential of sensitive early diagnostic tools of commercial ELISAs, based on the detection of these two biomarkers, was evaluated in serum samples of 704 Holstein Friesian cows (566 infected animals and 138 control animals from PTB-free farms). For this evaluation, infected animals were classified into three groups, according to the type of histological lesions present in their gut tissues: focal ( = 447), multifocal ( = 59), and diffuse ( = 60). The ELISA based on the detection of ABCA13 was successfully validated showing good discriminatory power between animals with focal lesions and control animals (sensitivity 82.99% and specificity 80.43%). Conversely, the MMP8-based ELISA showed a poor discriminatory power between the different histological groups and non-infected controls. The ABCA13-based ELISA showed a higher diagnostic value (0.822) than the IDEXX ELISA (0.517), the fecal bacterial isolation (0.523) and the real-time PCR (0.531) for the detection of animals with focal lesions. Overall, our results indicate that this ABCA13 ELISA greatly improves the identification of subclinically infected animals with focal lesions that are undetectable using current diagnostic methods.
牛副结核病（PTB）是由副结核分枝杆菌亚种（Map）引起的一种慢性肠炎，在全球范围内造成严重的经济影响。感染Map的动物可能多年无症状，但会将分枝杆菌传播给牛群中的其他成员。因此，准确检测亚临床感染动物对于疾病控制至关重要。在之前的一项RNA测序研究中，我们鉴定出了几种在患有不同PTB相关组织学病变的奶牛全血中与未检测到病变的对照动物相比过度表达的mRNA。其中两种mRNA编码的蛋白质，即ATP结合盒亚家族A成员13（ABCA13）和基质金属肽酶8（MMP8），在患有局灶性组织学病变的动物全血中显著过度表达，局灶性组织学病变是该疾病亚临床阶段最常见的病理形式。在本研究中，基于检测这两种生物标志物的商业ELISA敏感早期诊断工具的潜力，在704头荷斯坦弗里生奶牛（566头感染动物和138头来自无PTB农场的对照动物）的血清样本中进行了评估。为了进行此评估，根据其肠道组织中存在的组织学病变类型，将感染动物分为三组：局灶性（=447）、多灶性（=59）和弥漫性（=60）。基于检测ABCA13的ELISA成功得到验证，显示出在患有局灶性病变的动物和对照动物之间具有良好的区分能力（敏感性82.99%，特异性80.43%）。相反，基于MMP8的ELISA在不同组织学组和未感染对照之间显示出较差的区分能力。基于ABCA13的ELISA在检测患有局灶性病变的动物时，显示出比IDEXX ELISA（0.517）、粪便细菌分离（0.523）和实时PCR（0.531）更高的诊断价值（0.822）。总体而言，我们的结果表明，这种ABCA13 ELISA大大提高了对使用当前诊断方法无法检测到的患有局灶性病变的亚临床感染动物的识别能力。
