嗜热链球菌多位点序列分型及其特性测定

Multilocus Sequence Typing and Determining the Characteristics of Streptococcus thermophilus

本文旨在研究嗜热链球菌多位点序列分型方法的可行性。利用多位点序列分型技术,对实验室保藏的8株和全基因组公布的6株嗜热链球菌进行基因分型,并分析菌株的同源性,最后测定8株嗜热链球菌的产酸速率和蛋白质水解等表型特征。结果显示8株实验室菌株分属于4种基因型,6株全基因组菌株分属于5个基因型;菌株亲缘关系远近不一,其中分离自中国的ND03、MN-ZLW-002和0#具有较高同源性,分离自新疆酸奶的09086、09087和09088具有较高同源性,分离自内蒙古酸奶的菌株09067、09078和09079与分离自法国酸奶的JIM8232具有较高同源性,分离自法国发酵剂的s4与分离自法国酸奶的CNRZ1066具有较高同源性;8株实验室菌株的产酸速率和蛋白质水解具有菌株特异性,且表型特性与基因分型基本一致。多位点序列分型可对嗜热链球菌进行有效分型。

The aim of this study was to investigate the feasibility of multilocus sequence typing for Streptococcus thermophilus. Multilocus sequence typing technology was used to genotype eight in-house S. thermophilus strains and an additional six S. thermophilus strains for which whole-genome sequences have been published. The homology of these strains was also analyzed. Phenotypic characteristics including acid production rate and protein hydrolysis were determined for the eight in-house S. thermophilus strains. The results showed that these eight strains belonged to four genotypes, whereas the other six strains belonged to five genotypes. The phylogenetic relationships among all strains varied. Among them, ND03, MN-ZLW-002, and 0#, isolated from China, had relatively high homology; 09086, 09087, and 09088, isolated from Xinjiang yogurt, had relatively high homology; 09067, 09078, and 09079, isolated from Inner Mongolia yogurt, and JIM8232, isolated from French yogurt, had relatively high homology; and s4, isolated from a French fermentation agent, and CNRZ1066, isolated from French yogurt, had relatively high homology. The acid production rates and protein hydrolysis of the eight in-house strains were strain specific, and the phenotypic properties were largely in accord with the genotypes. In summary, multilocus sequence typing is effective for the genotyping of S. thermophilus strains.