Serrano-Moreno B A, Romero T A, Arriaga C, Torres R A, Pereira-Suárez A L, García-Salazar J A, Estrada-Chávez C
Facultad de Estudios Superiores-Cuautitlán, Universidad Nacional Autonoma de Mexico (UNAM), Estado de México, Mexico.
Zoonoses Public Health. 2008 Jun;55(5):258-66. doi: 10.1111/j.1863-2378.2008.01125.x.
We evaluated by nested PCR reaction, different cow secretions from a herd with 48% of prevalence of bovine tuberculosis (BTB), seeking to determine niches where Mycobacterium bovis could be found. Postmortem examination of 18 (75%) tuberculin reacting cows allowed demonstrates BTB-compatible lesions in six, all of them PCR positives in milk and four in colostra samples. Our results showed that up to 62% of the colostra analysed contained M. bovis DNA, whereas only 18% of milk gave a positive reaction. Moreover, in bronchoalveolar lavages from cattle with compatible lesions in lungs or lymph nodes, where macrophages account up to 90% of cells, we did not find evidences of M. bovis. Altogether, these results suggest that differences in the anti-bacterial capacity of bovine macrophages, dependent upon microenvironment and organ-specific factors, exist. Alternatively, we hypothesize that hypoxic conditions that are encountered in mammary glands macrophages could induce M. bovis entrance into a 'dormancy-like' state, and that the high number of colostra samples were M. bovis was detected, could be an indicator of reactivation during 'peripartum'.
我们通过巢式PCR反应，对一群牛结核病（BTB）患病率为48%的牛群的不同分泌物进行了评估，旨在确定可能发现牛分枝杆菌的生态位。对18头（75%）结核菌素反应阳性的奶牛进行死后检查，结果显示其中6头有与BTB相符的病变，所有这些奶牛的牛奶样本PCR检测均为阳性，4头初乳样本PCR检测为阳性。我们的结果表明，高达62%的分析初乳样本含有牛分枝杆菌DNA，而只有18%的牛奶样本呈阳性反应。此外，在肺部或淋巴结有相符病变的牛的支气管肺泡灌洗样本中，巨噬细胞占细胞总数的90%，我们未发现牛分枝杆菌存在的证据。总之，这些结果表明，牛巨噬细胞的抗菌能力存在差异，这取决于微环境和器官特异性因素。或者，我们推测乳腺巨噬细胞中遇到的缺氧条件可能会诱导牛分枝杆菌进入“类似休眠”状态，并且检测到大量初乳样本中有牛分枝杆菌，这可能是“围产期”重新激活的一个指标。
