贵州省2株牛种布鲁氏菌分子流行病学特征分析

目的 分析贵州省牛种布鲁氏菌分子流行病学特征，为牛种布鲁氏菌病疫情的防控提供科学依据。方法 采用BCSP31-PCR及AMOS-PCR技术对经传统方法鉴定为牛种布鲁氏菌的2株分离株进行属/种复核，采用基于布鲁氏菌rpoB基因的单核苷酸多态性分析了解其rpoB基因型，采用MLVA-16技术进行MLVA分型，了解其与国内牛种布鲁氏菌的聚类关系，采用MLST技术分析其序列型及其与国内菌株间的遗传进化关系。结果 2株分离株经BCSP31-PCR和AMOS-PCR技术被鉴定为布鲁氏菌属细菌，未能明确其具体种型；其rpoB基因型相同；MLVA分型与新疆牛种布鲁氏菌共享同一MLVA-16型(4-5-3-12-2-2-3-1-6-43-8-5-5-5-3-3); MLST分析鉴定2株菌均为ST2型，最小间距图显示2株菌与布鲁氏菌属内的牛种布鲁氏菌遗传距离最近，属同一个遗传复合体。结论 贵州省2株牛种布鲁氏菌分离株间的遗传距离近，与新疆牛种3型布鲁氏菌为同一MLVA型，提示分离株引起的感染可能为外省输入。

Molecular epidemiological characterization of two strains of Brucella abortus in Guizhou Province

The molecular epidemiological characteristics of Brucella abortus (B. abortus) in Guizhou Province were studied to provide a scientific basis for the prevention and control of brucellosis. Two isolates were identified as Brucella spp. strains through BCSP31-PCR and AMOS-PCR techniques, but the specific species type could not be identified. In this study, MLVA, MLST, and rpoB genotyping techniques were used to study the molecular epidemiological characteristics of the two isolates. The rpoB genotypes of the two isolates were consistently based on single nucleotide polymorphism analysis of the Brucella rpoB gene. To understand the relationship between the isolates and domestic B. abortus, we clustered the isolates with representative strains of domestic B. abortus. Cluster analysis based on MLVA typing data indicated that two isolates shared an MLVA-16 type (4-5-3-12-2-2-3-1-6-43-8-5-5-5-3-3) with B. abortus from Xinjiang. These isolated strains were identified as type ST2 through MLST analysis. To understand the genetic relationship between the isolates and domestic B. abortus, we constructed a minimum spanning tree based on MLST typing data, which indicated the isolates were most closely related to B. abortus and belonged to the same genetic complex. Therefore, a close genetic distance was observed between the two isolates from Guizhou Province, and the isolates shared an MLVA type with B. abortus from Xinjiang, thus suggesting that the infection was caused by isolates that might have been introduced from outside the province.