食源性空肠弯曲菌的分子分型及其遗传多样性分析

Molecular Typing of Foodborne Campylobacter jejuni and Analysis of Its Genetic Diversity

为了解在2012~2014年从中国不同城市分离到的食源性空肠弯曲菌的遗传多样性特征,本研究采用多序列位点分型(multilocus sequencing typing,MLST)的方法对分离到的33株食源性空肠弯曲菌进行分子分型。研究中,对33株菌株的管家基因使用7对不同的引物进行PCR扩增,并对扩增的产物使用凝胶电泳鉴定后进行测序。将测序结果同Pub MLST中Campylobacter数据库进行比对,以获得对应菌株ST型,并提交新的ST型数据。利用其MLST数据构建进化树和最小生成树。结果显示33株食源性空肠弯曲菌可以分为27个ST型,其中有14种为新的ST型,可形成11种克隆复合体,优势克隆复合体为CC22和CC45,部分菌株的CC型也曾在临床上发现。共存在91种核苷酸多态性位点,部分等位基因之间存在重组。这表明在2012-2014年间分离得到的菌株具有丰富的遗传多样性,并且有潜在致病风险。

In order to understand the genetic diversity of food-borne Campylobacter jejuni isolated in 2012~2014 from different cities of China, multilocus sequencing typing(MLST) was used for molecular typing of the 33 isolated strains. In the study, the housekeeping genes of 33 strains were amplified by PCR using 7 different pairs of primers, and the amplified products were identified by gel electrophoresis and sequenced. The sequencing results were compared with the Campylobacter database of PubMLST to obtain the corresponding sequence types, and the data of the new sequence type were submitted to the curator. A phylogenetic tree and minimum spanning tree were constructed according to MLST data. The results showed that 33 food-borne C. jejuni strains could be divided into 27 STs, of which 14 were new STs. They could form 11 clonal complexes, with the dominant clonal complexes being CC22 and CC45, and some CC-types were found clinically. There were 91 nucleotide polymorphism sites, with some alleles being recombined. These results demonstrate the genetic diversity of the strains isolated between 2012 and 2014 and their potential pathogen risks.