Linz Bodo, Mukhtar Nadia, Shabbir Muhammad Zubair, Rivera Israel, Ivanov Yury V, Tahir Zarfishan, Yaqub Tahir, Harvill Eric T
Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States.
Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States.
Front Microbiol. 2018 Nov 6;9:2616. doi: 10.3389/fmicb.2018.02616. eCollection 2018.
The human pathogen has emerged as a frequent cause of hospital-acquired infections, but infection of animals has rarely been observed. Here we analyzed an outbreak of epidemic pneumonia killing hundreds of sheep on a farm in Pakistan and identified as the infecting agent. A pure culture of strain AbPK1 isolated from lungs of sick animals was inoculated into healthy sheep, which subsequently developed similar disease symptoms. Bacteria re-isolated from the infected animals were shown to be identical to the inoculum, fulfilling Koch's postulates. Comparison of the AbPK1 genome against 2283 genomes from the NCBI database revealed that AbPK1 carries genes for unusual surface structures, including a unique composition of iron acquisition genes, genes for O-antigen synthesis and sialic acid-specific acetylases of cell-surface carbohydrates that could enable immune evasion. Several of these unusual and otherwise rarely present genes were also identified in genomes of phylogenetically unrelated isolates from combat-wounded US military from Afghanistan indicating a common gene pool in this geographical region. Based on core genome MLST this virulent isolate represents a newly emerging lineage of Global Clone 2, suggesting a human source for this disease outbreak. The observed epidemic, direct transmission from sheep to sheep, which is highly unusual for , has important consequences for human and animal health. First, direct animal-to-animal transmission facilitates fast spread of pathogen and disease in the flock. Second, it may establish a stable ecological niche and subsequent spread in a new host. And third, it constitutes a serious risk of transmission of this hyper-virulent clone from sheep back to humans, which may result in emergence of contagious disease amongst humans.
这种人类病原体已成为医院获得性感染的常见原因，但很少观察到其感染动物的情况。在此，我们分析了巴基斯坦一个农场爆发的导致数百只绵羊死亡的流行性肺炎疫情，并确定 为感染病原体。将从患病动物肺部分离出的AbPK1菌株的纯培养物接种到健康绵羊体内，这些绵羊随后出现了类似的疾病症状。从感染动物身上重新分离出的细菌与接种物相同，满足了科赫法则。将AbPK1基因组与NCBI数据库中的2283个 基因组进行比较，结果显示AbPK1携带了一些不同寻常的表面结构基因，包括独特组成的铁获取基因、O抗原合成基因以及细胞表面碳水化合物的唾液酸特异性乙酰化酶基因，这些基因可能有助于免疫逃避。在来自阿富汗的美国受伤军人的系统发育无关的 分离株基因组中也发现了其中一些不同寻常且很少出现的基因，这表明该地理区域存在一个共同的基因库。基于核心基因组多位点序列分型，这种毒力分离株代表了全球克隆2的一个新出现的谱系，表明此次疾病爆发的源头是人类。观察到的这种在绵羊之间直接传播的疫情，对于 来说非常罕见，对人类和动物健康都有重要影响。首先，动物之间的直接传播有利于病原体和疾病在羊群中快速传播。其次它可能会建立一个稳定的生态位并随后在新宿主中传播。第三，它构成了这种高毒力克隆从绵羊传播回人类的严重风险，这可能导致人类之间出现传染病。
