Department of Biology, Preparatory Institute for Engineering Studies, Sfax, University of Sfax-Tunisia.
Department of Life Sciences, Research Laboratory of Environmental Toxicology-Microbiology and Health (LR17ES06), Faculty of Sciences, Sfax, University of Sfax-Tunisia.
PLoS Negl Trop Dis. 2019 Sep 18;13(9):e0007707. doi: 10.1371/journal.pntd.0007707. eCollection 2019 Sep.
In Tunisia, almost 77% of clinically and bacteriologically diagnosed cases of extrapulmonary tuberculosis (EPTB) are zoonotic TB, caused by M. bovis. Although several studies have analyzed bovine TB in cattle in Tunisia, no study has evaluated the risk of transmission to humans in such an endemic country. We aimed to study the genetic diversity of M. bovis human isolates, to ascertain the causes of human EPTB infection by M. bovis and to investigate the distribution and population structure of this species in Tunisia.
A total of 110 M. bovis isolates taken from patients with confirmed EPTB were characterized by spoligotyping and MIRU-VNTR typing methods.
Among the 15 spoligotypes detected in our study, 6 (SB0120, SB0121, SB2025, SB1200, SB1003 and SB0134) were the most prevalent (83.5%) of which SB0120, SB0121 and SB2025 were the most prevailing. MIRU-VNTR typing method showed a high genotypic and genetic diversity. The genetic differentiation based on MIRU-VNTR was significant between populations from South East (Tataouine, Medenine) and Central West (Gafsa, Sidi Bouzid, Kasserine) regions. Of note, 13/15 (86.7%) spoligotypes detected in our study were previously identified in cattle in Tunisia with different frequencies suggesting a peculiar ability of some genotypes to infect humans. Using combined spoligotyping and MIRU-VNTR method, a high clustering rate of 43.9% was obtained. Our results underlined that human EPTB due to M. bovis was more commonly found in female gender and in young patients. Most of our patients, 66.4% (73/110) were raw milk or derivatives consumers, whereas 30.9% (34/110) patients would have contracted EPTB through contact with livestock. The findings suggest that the transmission of Zoonotic TB caused by M. bovis to humans mainly occurred by oral route through raw milk or derivatives.
Our study showed the urgent need of a better veterinary control with the implementation of effective and comprehensive strategies in order to reach a good protection of animals as well as human health.
在突尼斯，近 77%的临床和细菌学诊断为肺外结核病（EPTB）病例为动物源性结核病（由 M. bovis 引起）。尽管已有多项研究分析了突尼斯牛中的牛型结核分枝杆菌，但尚无研究评估该种疾病在这种流行地区向人类传播的风险。我们旨在研究人类 M. bovis 分离株的遗传多样性，确定由 M. bovis 引起的人类 EPTB 感染的原因，并调查该物种在突尼斯的分布和种群结构。
对 110 例确诊为 EPTB 的患者的 M. bovis 分离株进行 spoligotyping 和 MIRU-VNTR 分型方法鉴定。
在我们的研究中检测到的 15 种 spoligotypes 中，有 6 种（SB0120、SB0121、SB2025、SB1200、SB1003 和 SB0134）最为常见（83.5%），其中 SB0120、SB0121 和 SB2025 最为流行。MIRU-VNTR 分型方法显示出较高的基因型和遗传多样性。基于 MIRU-VNTR 的遗传分化在东南部（Tataouine、Medenine）和中西部（Gafsa、Sidi Bouzid、Kasserine）地区的人群之间存在显著差异。值得注意的是，在我们的研究中检测到的 13/15（86.7%）种 spoligotypes 以前在突尼斯的牛中也有发现，但其频率不同，这表明某些基因型具有感染人类的特殊能力。采用 spoligotyping 和 MIRU-VNTR 联合方法，获得了 43.9%的高聚类率。我们的研究结果表明，由于 M. bovis 引起的人肺外结核病更常见于女性和年轻患者。我们的大多数患者（66.4%，73/110）为生奶或奶制品消费者，而 30.9%（34/110）的患者则通过接触家畜而感染 EPTB。这些发现表明，牛型结核分枝杆菌引起的动物源性结核病主要通过生奶或奶制品经口传播。
我们的研究表明，迫切需要更好的兽医控制，实施有效的综合策略，以达到良好的动物和人类健康保护。
