Comparative Genome Analyses of Streptococcus suis Isolates from Endocarditis Demonstrate Persistence of Dual Phenotypic Clones.
Comparative Genome Analyses of Streptococcus suis Isolates from Endocarditis Demonstrate Persistence of Dual Phenotypic Clones.
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DOI：
10.1371/journal.pone.0159558
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Sekizaki T
中科院分区：
文献类型：
--
作者：
Tohya M;Watanabe T;Maruyama F;Arai S;Ota A;Athey TB;Fittipaldi N;Nakagawa I;Sekizaki T
许多细菌物种作为具有不同表型的异质克隆共存于同一生态位中;然而，对多表型细菌引起的感染性疾病的理解仍然有限。在本研究中，包囊在分离的猪病原体猪链球菌持续性心内膜炎病变进行了检查。包封和未包封的S.在59份心内膜炎样本中，有26份发现了suis分离株。分离株为血清2型，属于两种不同的序列类型（ST），ST 1和ST 28。对来自26个样品的26对包封和未包封的分离株中的每一个的基因组进行测序。数据显示，每对分离物在cps基因中具有一个或多个独特的非同义突变，并且来自相同样品的封装和未封装的分离物彼此最接近。成对比较的CPS基因的序列在7对封装和未封装的分离株确定插入/缺失（indels）范围从1到104 bp的未封装的分离株的不同CPS基因。通过与cps表达载体反式互补，在未包封的分离物的子集中恢复了荚膜表达。对分离株共有基因含量的检测表明，ST 28对的突变频率高于ST 1对。ST 28菌株中移动的遗传元件内的基因是突变热点。综上所述，我们的研究结果表明，双表型（封装和未封装）细菌克隆的共存，并表明，双表型出现在每个农场独立的CPS基因的自发突变的手段。
Many bacterial species coexist in the same niche as heterogeneous clones with different phenotypes; however, understanding of infectious diseases by polyphenotypic bacteria is still limited. In the present study, encapsulation in isolates of the porcine pathogen Streptococcus suis from persistent endocarditis lesions was examined. Coexistence of both encapsulated and unencapsulated S. suis isolates was found in 26 out of 59 endocarditis samples. The isolates were serotype 2, and belonged to two different sequence types (STs), ST1 and ST28. The genomes of each of the 26 pairs of encapsulated and unencapsulated isolates from the 26 samples were sequenced. The data showed that each pair of isolates had one or more unique nonsynonymous mutations in the cps gene, and the encapsulated and unencapsulated isolates from the same samples were closest to each other. Pairwise comparisons of the sequences of cps genes in 7 pairs of encapsulated and unencapsulated isolates identified insertion/deletions (indels) ranging from one to 104 bp in different cps genes of unencapsulated isolates. Capsule expression was restored in a subset of unencapsulated isolates by complementation in trans with cps expression vectors. Examination of gene content common to isolates indicated that mutation frequency was higher in ST28 pairs than in ST1 pairs. Genes within mobile genetic elements were mutation hot spots among ST28 isolates. Taken all together, our results demonstrate the coexistence of dual phenotype (encapsulated and unencapsulated) bacterial clones and suggest that the dual phenotypes arose independently in each farm by means of spontaneous mutations in cps genes.