Bacterial Zoonoses of Livestock, Operational Directorate Bacterial Diseases, Veterinary and Agrochemical Research Centre, VAR-CODA-CERVA, Brussels, Belgium.
PLoS One. 2013 Jun 28;8(6):e67622. doi: 10.1371/journal.pone.0067622. Print 2013.
Q-fever is a zoonosis caused by the gram-negative obligate intracellular pathogen Coxiella burnetii. Since its discovery, and particularly following the recent outbreaks in the Netherlands, C. burnetii appeared as a clear public health concern. In the present study, the infectious potential displayed by goat and cattle isolates of C. burnetii was compared to a reference strain (Nine Mile) using both in vitro (human HeLa and bovine macrophage cells) and in vivo (BALB/c mice) models. The isolates had distant genomic profiles with one--the goat isolate--being identical to the predominant strain circulating in the Netherlands during the 2007-2010 outbreaks. Infective doses were established with ethidium monoazide-PCR for the first time here applied to C. burnetii. This method allowed for the preparation of reproducible and characterized inocula thanks to its capacity to discriminate between live and dead cells. Globally, the proliferative capacity of the Nine Mile strain in cell lines and mice was higher compared to the newly isolated field strains. In vitro, the bovine C. burnetii isolate multiplied faster in a bovine macrophage cell line, an observation tentatively explained by the preferential specificity of this strain for allogeneic host cells. In the BALB/c mouse model, however, the goat and bovine isolates multiplied at about the same rate indicating no peculiar hypervirulent behavior in this animal model.
Q 热是一种由革兰氏阴性需氧细胞内病原体贝纳柯克斯体引起的动物传染病。自发现以来，尤其是在荷兰最近的疫情爆发后，贝纳柯克斯体已成为一个明显的公共卫生关注点。在本研究中，使用体外（人 HeLa 和牛巨噬细胞）和体内（BALB/c 小鼠）模型，比较了山羊和牛分离株的传染性与参考株（九英里株）的差异。这些分离株具有不同的基因组特征，其中一个山羊分离株与 2007-2010 年期间荷兰流行的主要菌株完全相同。本研究首次应用吖啶橙单叠氮 PCR 来确定感染剂量，该方法能够区分活细胞和死细胞，从而制备出可重复且具有特征的接种物。总体而言，九英里株在细胞系和小鼠中的增殖能力高于新分离的田间分离株。在体外，牛贝纳柯克斯体分离株在牛巨噬细胞系中繁殖更快，这种观察结果可能是由于该菌株对同种异体宿主细胞的优先特异性所致。然而，在 BALB/c 小鼠模型中，山羊和牛分离株的繁殖速度大致相同，这表明在该动物模型中没有特别的高致病性行为。
