Table_3_A Predominant Clonal Thromboembolic Meningoencephalitis Group of Histophilus somni Assigned by Major Outer Membrane Protein Gene Sequencing and Pulsed-Field Gel Electrophoresis.XLSX

Histophilus somni, a member of the family Pasteurellaceae, causes a variety of diseases, including thromboembolic meningoencephalitis (TEME) and respiratory diseases, which result in considerable economic losses to the cattle and sheep industries. In this study, 132 chronologically diverse isolates from cattle in Japan and 68 isolates from other countries comprising 49 from cattle and 19 from sheep were characterized using major outer membrane protein (MOMP) gene sequence and pulsed-field gel electrophoresis (PFGE) analyses. The H. somni isolates formed nine MOMP genetic clades (clade Ia, Ib, and II–VIII) and 10 PFGE clusters (HS1–HS10). Except for two (1.0%), all isolates fell into one of the nine MOMP genetic clades, while 62 (31.0%) isolates belonged to no PFGE cluster. MOMP genetic clade Ia and PFGE cluster HS1 were the major groups, and all HS1 isolates possessed the clade Ia MOMP gene. Isolates from TEME cases were significantly associated with these major groups (chi-square test, p < 0.0001), as 88.2% of the TEME isolates belonged to MOMP genetic clade Ia and PFGE cluster HS1, which formed the most predominant clonal group. After an inactivated vaccine using an HS1 strain with the clade Ia MOMP gene was introduced in Japan in late 1989, the number of TEME cases and isolates assigned into the clonal group decreased simultaneously. However, the proportions of clade Ia and cluster HS1 isolates from TEME cases remained high after 1990. These results suggest a close association of TEME with PFGE cluster HS1 and MOMP genetic clade Ia, and imply the presence of factors or characteristics commonly possessed by those strains that contribute to the development of TEME.

睡眠嗜血杆菌（Histophilus somni）隶属于巴斯德菌科（Pasteurellaceae），可引发血栓栓塞性脑膜脑炎（thromboembolic meningoencephalitis, TEME）、呼吸系统疾病等多种病症，给牛、羊养殖业造成了显著的经济损失。本研究采用主要外膜蛋白（major outer membrane protein, MOMP）基因测序与脉冲场凝胶电泳（pulsed-field gel electrophoresis, PFGE）分析技术，对132株采自日本牛群、涵盖不同年代的分离株，以及68株来自其他国家的分离株（其中49株源自牛、19株源自羊）进行了分型鉴定。结果显示，睡眠嗜血杆菌分离株共形成9个MOMP遗传进化枝（进化枝Ia、Ib及II~VIII）与10个PFGE聚类群（HS1~HS10）。除2株（占比1.0%）外，其余所有分离株均归入上述9个MOMP遗传进化枝之一；但有62株（占比31.0%）未归入任何PFGE聚类群。MOMP遗传进化枝Ia与PFGE聚类群HS1为优势类群，且所有HS1菌株均携带Ia型MOMP基因。来自TEME病例的分离株与这两类优势类群显著相关（卡方检验，chi-square test，p < 0.0001）：88.2%的TEME分离株属于MOMP遗传进化枝Ia与PFGE聚类群HS1，该类群构成了最主要的克隆群。1989年末日本引入搭载Ia型MOMP基因的HS1株灭活疫苗后，TEME病例数与归入该克隆群的分离株数量同步下降。但1990年后，TEME病例中进化枝Ia与聚类群HS1分离株的占比仍维持在较高水平。上述结果表明，TEME与PFGE聚类群HS1及MOMP遗传进化枝Ia存在紧密关联，提示该类菌株所共有的特征或因子可促进TEME的发生发展。