Yue Ruichao, Liu Chunfa, Barrow Paul, Liu Fei, Cui Yongyong, Yang Lifeng, Zhao Deming, Zhou Xiangmei
State Key Laboratories for Agrobiotechnology, Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193 China.
School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD UK.
Gut Pathog. 2016 Mar 22;8:9. doi: 10.1186/s13099-016-0092-6. eCollection 2016.
Mycobacterium avium subspecies paratuberculosis (Map) causes Johne's disease in domestic and wild ruminants. It has been a debate that whether Map can cause Crohn's disease in human. To our knowledge there is no report about molecular characterization of Map in China, although several Map strains have been reported in other country. The objectives of this study was to know the recent prevalence of Johne's disease in dairy farms in Shandong province, and have a better understanding of genotypic distribution of Map in China.
Johne's disease was detected from 1038 individuals in 19 dairy farms by ELISA. Map in fecal and milk specimens was identified by Ziehl-Neelsen staining and confirmed using PCR-REA. In addition, frozen sections of ileum and mesenteric lymph nodes from two Map shedding cows were performed to observe the histopathological changes. Next-generation sequencing technology was performed to get whole genome sequences.
A total of 121 (11.7 %) animals were positive for Map antibody from 1038 sera tested, and 11 (57.9 %) dairy herds were positive for Map antibody. Typically histopathologic changes were observed in mesenteric lymph nodes. We have successfully isolated two Map strains, which both were Map-C. The current genome-wide analysis showed that the genome size of our isolates are respectively 4,750,273 and 4,727,050 bp with a same G + C content of 69.3 %, and the numbers of single nucleotide polymorphisms (SNPs) against Map K-10 are respectively 292 and 296.
Map is a prevalent pathogen among dairy cattle in China. This study successfully isolated two Map strains from one Chinese dairy herd with signs of diarrhoea, and identified that the two isolates were both Map-C. Furthermore, these isolates were most closely related to Map K-10.
副结核分枝杆菌（Map）可引起家畜和野生反刍动物的副结核病。Map是否会导致人类克罗恩病一直存在争议。据我们所知，中国尚无关于Map分子特征的报道，尽管其他国家已报道了几株Map菌株。本研究旨在了解山东省奶牛场副结核病的近期流行情况，并更好地了解中国Map的基因型分布。
采用ELISA法对19个奶牛场的1038头个体进行副结核病检测。通过萋-尼氏染色法鉴定粪便和牛奶样本中的Map，并使用PCR-REA进行确认。此外，对两头排菌奶牛的回肠和肠系膜淋巴结进行冰冻切片，观察组织病理学变化。采用新一代测序技术获取全基因组序列。
在检测的1038份血清中，共有121头（11.7%）动物Map抗体呈阳性，11个（57.9%）奶牛群Map抗体呈阳性。在肠系膜淋巴结中观察到典型的组织病理学变化。我们成功分离出两株Map菌株，均为Map-C型。目前的全基因组分析表明，我们分离株的基因组大小分别为4750273和4727050 bp，G+C含量均为69.3%，与Map K-10相比，单核苷酸多态性（SNP）数量分别为292和296。
Map是中国奶牛中的一种流行病原体。本研究成功从一头有腹泻症状的中国奶牛群中分离出两株Map菌株，并鉴定这两株分离株均为Map-C型。此外，这些分离株与Map K-10关系最为密切。
