内蒙古布鲁氏菌临床分离株多位点序列分型研究

目的探讨临床分离布鲁氏菌的种群结构和遗传进化特征。方法布鲁氏菌标准参考菌株羊种16M,牛种544A和猪种1 330 S作为对照菌株,采用多位点序列分型(Multiple locus sequence typing,MLST)方法对内蒙古地区分离的116株羊种布鲁氏菌进行分析,确定待测菌株的序列型(STs),用软件BioNumerics(Version 5.0)构建菌株的最小生成树。结果116株羊种布鲁氏菌全部为ST8型,9个MLST位点的变异完全相同,分离株种群结构单一;羊种菌的生物型与ST型无明显关联,ST8型菌系该地区的主要流行菌种,并与内蒙古地区先前分离羊种布鲁氏菌进化程度相同,且有密切的亲缘关系。结论羊种布鲁氏菌的序列分型(ST)与常规生物分型存在差异,ST8型菌可能具有较强的环境适应性和致病性。MLST是一种较好的羊布鲁氏菌种群和进化关系研究方法,但更适合于具有较大时间跨度和地理分布菌株间的流行病学调查。

Multilocus sequence typing of Brucella clinical isolated strains in Inner Mongolia

We aimed to investigate the clinical isolates of Brucella melitensis characteristic of population structure and genetic evolution. Brucella standard reference strains of B. abortus 544A, B. melitensis 16M and B. suis 1 330 S were used as test control. A total 116 strains from Ulanqab of Inner Mongolia were analyzed by MLST to determine sequences types of strains; software BioNumerics was used to constructed minimum spanning tree. Results showed that 116 isolates of B. melitensis were all ST 8, the variation of the 9 MLST loci was exactly the same, and the population structure of B. melitensis isolates was a single. There was no obviously relationship between biovar and ST in the case of B. melitensis, isolates belong to ST8 was major epidemic isolates in this region, and had closely genetic relationship and the same degree of evolution with strains from other district previously isolates of Inner Mongolia. The sequence typing of B. melitensis is different from conventional biotyping. ST8 Brucella may have strong ability to adapting environmental and pathogenicity; MLST is a helpful tool for B. melitensis species construction and evolutionary research, but it is more suitable to epidemiological survey for strains from larger span of time and widely geographical distribution.