Tuberculosis laboratory, Diagnostic Services Programme, ARC-Onderstepoort Veterinary Research, Private Bag, X 05, Onderstepoort, 0110. Pretoria, South Africa.
Tuberculosis laboratory, Diagnostic Services Programme, ARC-Onderstepoort Veterinary Research, Private Bag, X 05, Onderstepoort, 0110. Pretoria, South Africa.
Prev Vet Med. 2020 Apr;177:104980. doi: 10.1016/j.prevetmed.2020.104980. Epub 2020 Mar 31.
Members of the Mycobacterium tuberculosis complex (MTBC) bacteria, mainly Mycobacterium bovis (M. bovis), cause bovine tuberculosis (bTB) in livestock and wildlife animals. Confirmation of the disease is through culture and verification of the causative agent by molecular tests. In this study, we assessed the utility of the Xpert ® MTB/RIF Ultra assay, an automated molecular test originally designed to improve the detection of tuberculosis (TB) and rifampicin resistance in clinical sputum samples of human origin, by conducting a comparative evaluation with a culture based method routinely used at the Onderstepoort Veterinary Research (OVR). A total of 167 samples (tissue, n = 165; pus, n = 1; abscess, n = 1) from different wildlife and livestock animals (from 65 individual animals) were analyzed. Mycobacterium tuberculosis complex species was isolated in 63 (37.72 %) of the 167 samples, and was detected in 79 (47.3 %) of the samples by Xpert ® MTB/RIF Ultra assay. Based on the standard culture test, the diagnostic sensitivity and specificity of the Xpert ® MTB/RIF Ultra assay was found to be 95.24 % and 82 % respectively. All animals that were confirmed bTB positive by culture method were also found to be positive with the Xpert ® MTB/RIF Ultra assay in at least one sample (indicating a 100 % sensitivity of the method at the animal level). Non-tuberculous mycobacteria were isolated in 9 (3.4 %) of the samples analysed and none were detected by Xpert ® MTB/RIF Ultra assay, highlighting that this molecular test is highly specific. Xpert ® MTB/RIF Ultra assay was found to have great potential for the rapid diagnosis of the bTB in animals, hence allowing early intervention by regulatory authorities.
分枝杆菌复合群（MTBC）细菌的成员，主要是牛分枝杆菌（M. bovis），导致牲畜和野生动物的牛结核病（bTB）。该疾病的确认是通过培养和通过分子测试验证病原体。在这项研究中，我们评估了 Xpert ® MTB/RIF Ultra 检测的效用，这是一种最初设计用于提高人类来源临床痰样本中结核病（TB）和利福平耐药检测的自动化分子检测方法，通过与常规方法进行比较评价 Onderstepoort 兽医研究所（OVR）使用的方法。对来自不同野生动物和牲畜动物（来自 65 个个体动物）的 167 个样本（组织，n = 165；脓液，n = 1；脓肿，n = 1）进行了分析。在 167 个样本中的 63 个（37.72%）中分离出分枝杆菌复合群物种，并通过 Xpert ® MTB/RIF Ultra 检测在 79 个（47.3%）样本中检测到。根据标准培养试验，Xpert ® MTB/RIF Ultra 检测的诊断灵敏度和特异性分别为 95.24%和 82%。通过培养方法确认的所有 bTB 阳性动物在至少一个样本中也被 Xpert ® MTB/RIF Ultra 检测呈阳性（表明该方法在动物水平上的灵敏度为 100%）。在所分析的 9 个（3.4%）样本中分离出非结核分枝杆菌，并且都没有被 Xpert ® MTB/RIF Ultra 检测到，这突出表明该分子检测方法具有高度特异性。Xpert ® MTB/RIF Ultra 检测在动物中快速诊断 bTB 具有很大的潜力，因此允许监管机构进行早期干预。
