江西省致病性钩端螺旋体血清学和分子流行病学研究

目的 对2013年以来江西省致病性钩端螺旋体进行血清学、基因分型分析,以了解江西省钩端螺旋体血清学和分子流行病学特征。方法 对27株钩端螺旋体进行暗视野显微镜凝集试验确定血清群。PCR扩增16S rRNA基因、测序,确定基因种。利用MLST(multilocus sequence typing)研究进行基因分型分析,并应用BioNumerics (Version5.10)软件进行聚类分析。结果 血清群鉴定:27株菌株隶属于4个血清群,其中黄疸出血群为主要优势血清群,占59.26%,其次依次是爪哇群25.92%、澳洲群7.41%和巴达维亚群7.41%。基因种鉴定:27株菌株隶属于L. interrogans和L. borgpetersenii 2个致病性基因种,L. interrogans为江西省主要优势型别,占77.78%。MLST研究显示27株菌株隶属于5个ST型别,其中ST1为主要基因型,占59.26%。BioNumerics软件分析:27株菌株分为5个Clusters对应于5个ST型,MLST基因型别具有明显的地域性特征,而年代间变化不明显。结论 黄疸出血群为江西省主要流行血清群,L. interrogan为主要致病基因种,ST1为主要基因型,充分了解江西省钩体病血清学和分子流行病学特征将对钩体病防控和疫苗制备有一定的指导意义。

Molecular and serological characterization of pathogenic Leptospira in Jiangxi Province,China

In order to explore the molecular and serological characterization of pathogenic Leptospira in Jiangxi Province, a collection of 27 strains isolated from Jiangxi Province in China since 2013 were analyzed using Serogroup identification, 16S rRNA gene sequencing and multilocus sequence typing (MLST) in this study. Seven loci were chosen for genotyping in MLST analysis and the results were analyzed by BioNumerics (Version 5.10) softwares. Microscopic agglutination test (MAT) was conducted and a total of four serogroups were identified among 27 Leptospira strains. Serogroup Icterohaemorrhagiae was the most frequent serogroup, accounting for 59.26%, followed by Javanica 25.92%, Australis 7.41% and Bataviae 7.41%, respectively. 16S rRNA sequencing was conducted and two pathogenic species of L. interrogans and L. borgpetersenii were identified among the 27 isolates. L. interrogans was the most prevalence species, accounting for 77.78%, while the remaining 6 isolates were identified as pathogenic L. borgpetersenii. Five different sequence types (STs) were obtained By MLST. ST1 accounted for 59.26% and was the major genotype in Jiangxi Province in China. Phylogenetic analysis using BioNumerics softwares revealed that five major clusters (Cluster1 to Cluster5) corresponding to five ST types was identified among 27 isolates. Obvious epidemiological relationship was found between the distributions of STs and isolated location, but not across years. In this work, the results revealed that MLST analysis could be used to explore the genetic diversity and population structures of Leptospira. In this work, the results revealed that Serogroup Icterohaemorrhagiae was the most frequent serogroup, L. interrogans was the most prevalence species, and ST1 was the major genotype in Jiangxi Province in China. The detailed serological and molecular characteristics circulating in this region may provide new insights into the epidemiology of leptospirosis and vaccine design in China.