ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Yelahanka, Bengaluru 560064, Karnataka, India.
CCS-National Institute of Animal Health (NIAH), Baghpat 250609, Uttar Pradesh (UP), India.
Infect Genet Evol. 2020 Nov;85:104564. doi: 10.1016/j.meegid.2020.104564. Epub 2020 Sep 24.
Virulence associated and/or housekeeping/repetitive genes either in single or multiple copies are being extensively targeted for bacterial pathogen detection and differentiation in epidemiological studies. In the present study, isolation of Pasteurella multocida from different animals and their genetic profiling based on the capsular types, virulence and repetitive elements (ERIC/REP) were carried out. A total 345 clinical samples from apparently healthy and diseased (pneumonic, septicaemia) animals (sheep, goat, pig, cattle, buffalo and rabbits) from different geographical regions of Karnataka, Uttar Pradesh, Mizoram and Assam states of India were screened. A total of 32% of the samples were found positive, of which 41 P. multocida isolates recovered. Virulence profiling of isolates indicated that omp87, ompA, ptfA, sodA, sodC, nanB, fur and exbB were present in 100% of isolates. Whereas, prevalence of other genes were; nanH (90%), ompH (71%), pfhA (63%), plpB (80%), hsf-1 (12%), hsf-2 (37%), pmHAS (78%), toxA (73%), hgbA (37%), hgbB (81%), tbpA (78%) and fimA (98%), among isolates. There was no influence of host or place on prevalence of virulence genes when assessed by fitting a Hierarchial Bayesian ordinal regression model. There was correlation (positive and negative) between broad groups of virulence genes. Both repetitive gene profiles (ERIC and REP) generated multiple amplicons (~200 to ~4000 bp). Cluster analysis with ERIC profiles revealed 5 clusters and 3 non- typable isolates with higher discriminatory power (D = 0.7991) than the REP-PCR profiles (D = 00.734) which revealed 4 clusters and 6 non- typable isolates. The results showed that a considerable level of genetic diversity exists among circulating P. multocida isolates despite belonging to the same geographical origin. The genetic diversity or clustering based on either virulence or repetitive elements among isolates could be largely driven by multiple factors acting together which lead to manifestations of particular disease symptoms.
毒力相关和/或管家/重复基因无论是单一拷贝还是多个拷贝，都被广泛用于细菌病原体的检测和流行病学研究中的区分。本研究从不同动物中分离多杀巴斯德菌，并基于荚膜型、毒力和重复元件（ERIC/REP）对其进行遗传分析。从印度卡纳塔克邦、北方邦、米佐拉姆邦和阿萨姆邦不同地理位置的健康和患病（肺炎、败血症）动物（绵羊、山羊、猪、牛、水牛和兔子）的 345 份临床样本中进行了筛选。结果发现，32%的样本呈阳性，其中 41 株分离出多杀巴斯德菌。对分离株的毒力分析表明，omp87、ompA、ptfA、sodA、sodC、nanB、fur 和 exbB 存在于 100%的分离株中。而其他基因的流行率为：nanH（90%）、ompH（71%）、pfhA（63%）、plpB（80%）、hsf-1（12%）、hsf-2（37%）、pmHAS（78%）、toxA（73%）、hgbA（37%）、hgbB（81%）、tbpA（78%）和 fimA（98%）。通过拟合层次贝叶斯有序回归模型评估宿主或地点对毒力基因流行率的影响时，发现没有影响。广泛的毒力基因之间存在相关性（正相关和负相关）。两种重复基因图谱（ERIC 和 REP）均产生多个扩增子（200 至4000 bp）。ERIC 图谱聚类分析显示 5 个聚类和 3 个不可分型分离株，具有更高的区分能力（D=0.7991），而 REP-PCR 图谱（D=0.734）显示 4 个聚类和 6 个不可分型分离株。结果表明，尽管来自同一地理起源，但循环多杀巴斯德菌分离株之间存在相当程度的遗传多样性。基于毒力或重复元件的分离株的遗传多样性或聚类可能主要是由多种共同作用的因素驱动的，这些因素导致了特定疾病症状的表现。
