INIAV, IP - National Institute for Agrarian and Veterinary Research, Av. da República, Quinta do Marquês, Edifício Principal, Piso 1, 2780 -157 Oeiras, Portugal; cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Edifício C2, 4º Piso, Campo Grande, 1749-016 Lisboa, Portugal; BioISI - Biosystems & Integrative Sciences Institute, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
INIAV, IP - National Institute for Agrarian and Veterinary Research, Av. da República, Quinta do Marquês, Edifício Principal, Piso 1, 2780 -157 Oeiras, Portugal.
Vet Microbiol. 2020 Jan;240:108533. doi: 10.1016/j.vetmic.2019.108533. Epub 2019 Nov 30.
Portugal is one of the European Union countries with an ongoing eradication program for bovine tuberculosis (TB), which does not include systematic goat testing. However, surveillance in small ruminants is increasingly important, since goat and sheep can harbour Mycobacterium caprae and be an infection source to cattle with impact in the success of bovine TB control. Furthermore, the information regarding the epidemiology and biology of M. caprae is quite limited comparing to the cognate bovine-adapted ecotype, M. bovis. In this work, we applied spoligotyping and MIRU-VNTR (Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats) to M. caprae obtained between 2003 and 2014 from 55 animal hosts, including goat (n = 29), cattle (n = 21), sheep (n = 1) and wild boar (n = 4) from Portugal. The molecular analysis revealed a unique spoligotyping pattern (SB0157) and 24 MIRU types. Genotyping of serial M. caprae from herds with recurrent outbreaks enabled further discrimination of epidemiologically related isolates, supporting a clonal structure in Portugal and denoting the emergence of clonal diversity at the herd level, more apparent for MIRU4. Results suggest a founder effect and adaptive genotypic divergence, paving the way for sympatric speciation. Double allele findings at MIRU4 in over 20 % of infected animals indicates that co-infection and in vivo microevolution may be frequent in the goat-adapted ecotype. While polyclonal infection appears common in M. caprae epidemiology, the functional significance of subtle genotypic variations remains to be disclosed, namely at the interface with the host, to expand knowledge on the epidemiology and biology of this neglected ecotype.
葡萄牙是欧盟国家之一，正在进行牛结核病（TB）根除计划，该计划不包括对山羊进行系统检测。然而，对小反刍动物的监测越来越重要，因为山羊和绵羊可能携带分枝杆菌和牛分枝杆菌，成为牛结核病控制成功的感染源。此外，与同源牛适应生态型分枝杆菌相比，分枝杆菌的流行病学和生物学信息非常有限。在这项工作中，我们应用 spoligotyping 和 MIRU-VNTR（分枝杆菌插入重复单位-可变数串联重复）对 2003 年至 2014 年间从葡萄牙的 55 个动物宿主（包括山羊[ n = 29]、牛[ n = 21]、绵羊[ n = 1]和野猪[ n = 4]）获得的分枝杆菌进行了分析。分子分析显示了独特的 spoligotyping 模式（SB0157）和 24 种 MIRU 类型。对来自经常暴发疫情的畜群的连续分枝杆菌的基因分型，进一步区分了具有流行病学相关性的分离株，支持了葡萄牙的克隆结构，并指出了在畜群水平上克隆多样性的出现，MIRU4 更为明显。结果表明存在创始效应和适应性遗传分化，为同域物种形成铺平了道路。在超过 20%的感染动物中发现 MIRU4 的双等位基因表明，共感染和体内微进化可能在山羊适应生态型中很常见。虽然多克隆感染在分枝杆菌流行病学中很常见，但微妙的遗传变异的功能意义仍有待揭示，特别是在与宿主的接口处，以扩大对这一被忽视生态型的流行病学和生物学的认识。
