Barbier Elodie, Chantemesse Benoit, Rochelet Murielle, Fayolle Léon, Bollache Loïc, Boschiroli Maria Laura, Hartmann Alain
INRA, UMR 1347 Agroécologie, Dijon Cedex, France; Université de Bourgogne Franche Comté, Dijon Cedex, France.
INRA, UMR 1347 Agroécologie, Dijon Cedex, France.
Vet Microbiol. 2016 Apr 15;186:1-7. doi: 10.1016/j.vetmic.2016.01.025. Epub 2016 Feb 16.
Indirect transmission of Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), between wildlife and livestock is thought to occur by inhalation or ingestion of environmental substrates contaminated through animal shedding. The role of the soil fauna, such as earthworms, in the circulation of M. bovis from contaminated animal feces is of interest in the epidemiology of bTB. The objective of this study was to assess the impact of earthworm activity on M. bovis transfer from animal dung to castings and the surrounding soil. For this purpose, microcosms of soil containing the anecic earthworms Lumbricus terrestris were prepared and covered with cattle feces spiked with the M. bovis BCG strain Pasteur to carry out two separate experiments. The dissemination, the gut carriage and the excretion of M. bovis were all monitored using a specific qPCR-based assay. Our results showed that the earthworm L. terrestris was able to rapidly disseminate M. bovis from the contaminated cattle feces to the surrounding soil through casting egestion. Moreover, contaminated earthworms were shown to shed the bacteria for 4 days when transferred to a M. bovis-free soil. This study highlights for the first time the possible role of earthworms in the dissemination and the persistence of M. bovis in soils within bTB endemic areas.
牛结核分枝杆菌是牛结核病（bTB）的病原体，野生动物与家畜之间的牛结核分枝杆菌间接传播被认为是通过吸入或摄入因动物排泄物而受污染的环境基质发生的。土壤动物区系（如蚯蚓）在牛结核分枝杆菌从受污染动物粪便中的循环中所起的作用，在牛结核病流行病学中备受关注。本研究的目的是评估蚯蚓活动对牛结核分枝杆菌从动物粪便转移至蚓粪及周围土壤的影响。为此，制备了含有表栖蚯蚓（陆正蚓）的土壤微观模型，并用接种了牛结核分枝杆菌卡介苗巴斯德菌株的牛粪覆盖，以进行两项独立实验。使用基于定量聚合酶链反应（qPCR）的特定检测方法监测牛结核分枝杆菌的传播、肠道携带情况及排泄情况。我们的结果表明，陆正蚓能够通过排蚓粪将牛结核分枝杆菌从受污染的牛粪迅速传播至周围土壤。此外，当将受污染的蚯蚓转移至无牛结核分枝杆菌的土壤中时，它们会在4天内排出细菌。本研究首次强调了蚯蚓在牛结核病流行地区土壤中牛结核分枝杆菌传播和持续存在方面可能发挥的作用。
