Department of Infectious Microbiology, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
National Diagnostic and Research Veterinary Medical Institute "Prof. Dr. G. Pavlov", Sofia, Bulgaria.
Infect Genet Evol. 2020 Jul;81:104240. doi: 10.1016/j.meegid.2020.104240. Epub 2020 Feb 11.
Bovine tuberculosis (bTB) represents a significant economic burden to the agriculture. In spite of decades of the control program, Mycobacterium bovis infection levels in cattle in Bulgaria continued to rise over recent years. In order to gain a better understanding of the M. bovis diversity, we used spoligotyping for strain differentiation and the data were compared to the international databases Mbovis.org and SITVIT2 for shared type and clade assignment. Study sample included 30 M. tuberculosis complex isolates from cattle originating from different regions of Bulgaria. The isolates were subdivided by spoligotyping into 4 spoligotypes: 2 types shared by 20 and 8 isolates and 2 singletons. SITVIT2-defined types SIT645 and SIT647 belonged to the common and classical bovine ecotype M. bovis (9 isolates) while types SIT120 and SIT339 belonged to the M. caprae ecotype (21 isolates). A certain phylogeographic gradient of the spoligotypes and clades at the within-country level was observed: M. caprae was prevalent in the central/southwestern, while classical M. bovis in the northeastern Bulgaria. Whereas all four types have global or European circulation, neither was described in the neighboring Balkan countries. M. caprae isolates identified in this study mostly belong to the Central/Eastern European cluster. In summary, this study provided a first insight into phylogeography of M. bovis in Bulgaria and described, for the first time, M. caprae as an important infectious agent of bTB in this country.
牛型结核（bTB）对农业造成了巨大的经济负担。尽管控制计划已经实施了几十年，但近年来保加利亚牛群中 M. bovis 的感染水平仍在持续上升。为了更好地了解 M. bovis 的多样性，我们使用 spoligotyping 进行菌株分化，将数据与国际数据库 Mbovis.org 和 SITVIT2 进行比较，以确定共享类型和谱系分配。研究样本包括来自保加利亚不同地区的 30 株牛型结核分枝杆菌复合体分离株。这些分离株通过 spoligotyping 分为 4 种 spoligotypes：20 株和 8 株共享 2 种类型，2 种为单倍型。SITVIT2 定义的类型 SIT645 和 SIT647 属于常见的经典牛型 M. bovis（9 株），而类型 SIT120 和 SIT339 属于 M. caprae 生态型（21 株）。在国内水平上观察到 spoligotypes 和 clades 的一定地理梯度：M. caprae 在中部/西南部流行，而经典 M. bovis 在保加利亚东北部流行。虽然这四种类型在全球或欧洲都有流通，但在邻国巴尔干国家均未描述。本研究中鉴定的 M. caprae 分离株主要属于中欧/东欧群。总之，本研究首次提供了保加利亚 M. bovis 系统地理学的见解，并首次描述了 M. caprae 是该国 bTB 的重要传染性病原体。
