The blp Locus of Streptococcus pneumoniae Plays a Limited Role in the Selection of Strains That Can Cocolonize the Human Nasopharynx.
The blp Locus of Streptococcus pneumoniae Plays a Limited Role in the Selection of Strains That Can Cocolonize the Human Nasopharynx.
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肺炎链球菌的 blp 基因座在选择可在人鼻咽部共生的菌株中发挥有限的作用。
DOI：
10.1128/aem.01048-16
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发表时间：
2016
影响因子：
4.4
通讯作者：
Sá-Leão,Raquel
中科院分区：
文献类型：
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作者：
Valente,Carina;Dawid,Suzanne;Pinto,FranciscoR;Hinds,Jason;Simões,AlexandraS;Gould,KatherineA;Mendes,LuísA;deLencastre,Hermínia;Sá-Leão,Raquel
鼻咽定植对于肺炎链球菌的进化很重要，当多个菌株共存时，鼻咽定植为水平基因转移提供了机会。虽然肺炎球菌多个菌株的定植很常见，但影响菌株共存能力的因素尚不清楚。在所有已测序的肺炎链球菌中都发现了一个高度可变的细菌素样肽(Blp)基因座。这个基因控制细菌素的调节和分泌，细菌素是一种针对其他细菌的小肽。在这项研究中，我们分析了一系列共定植分离株，以评估该斑点对人类定植的影响，以确定细菌素分泌的竞争表型是否限制了共定植。我们鉴定了135份鼻咽标本，与两个或更多的菌株共存，总计285个分离物。所有菌株的blocus在信息素类型、细菌素/免疫含量和潜在的座位功能方面进行了遗传特征分析。通过重叠分析评估细菌素分泌抑制表型和位点活性。单次定殖(n=298)的分离株用于比较。共克隆菌株具有高度的白细胞体多样性；约三分之一的菌株在体外表现出抑制表型。尽管竞争的体外证据表明，肺炎球菌与受试者共定植与细菌信息素类型(P=0.577)、细菌素/免疫含量、菌斑活性(P=0.798)和抑制表型(P=0.716)无关。此外，当比较单一和共生的菌株时，没有观察到显著的差异。尽管在实验模型中有明确的证据表明blp介导的竞争，但我们的研究结果表明blplocus在限制肺炎球菌在人类体内共定植方面的作用有限。肺炎链球菌(肺炎球菌)在鼻咽的定植对肺炎球菌的进化是重要的，因为当多个菌株共存时，鼻咽代表水平基因转移的主要部位，这种现象称为共定殖化。在肺炎球菌生态学的背景下，了解肺炎球菌菌株如何在鼻咽的竞争环境中相互作用是最重要的。在这项研究中，我们使用了一组自然共存的肺炎球菌菌株的公正收集，并表明细菌经常用于竞争的生物过程-细菌素生产-并不是肺炎球菌在宿主中共存的决定性因素，这与实验模型中所显示的相反。
Nasopharyngeal colonization is important for Streptococcus pneumoniae evolution, providing the opportunity for horizontal gene transfer when multiple strains co-occur. Although colonization with more than one strain of pneumococcus is common, the factors that influence the ability of strains to coexist are not known. A highly variableblp(bacteriocin-like peptide) locus has been identified in all sequenced strains of S. pneumoniae. This locus controls the regulation and secretion of bacteriocins, small peptides that target other bacteria. In this study, we analyzed a series of cocolonizing isolates to evaluate the impact of theblplocus on human colonization to determine whether competitive phenotypes of bacteriocin secretion restrict cocolonization. We identified a collection of 135 nasopharyngeal samples cocolonized with two or more strains, totaling 285 isolates. Theblplocus of all strains was characterized genetically with regard to pheromone type, bacteriocin/immunity content, and potential for locus functionality. Inhibitory phenotypes of bacteriocin secretion and locus activity were assessed through overlay assays. Isolates from single colonizations (n= 298) were characterized for comparison. Cocolonizing strains had a high diversity ofblpcassettes; approximately one-third displayed an inhibitory phenotypein vitro. Despitein vitroevidence of competition, pneumococci cocolonized the subjects independently ofblppheromone type (P= 0.577), bacteriocin/immunity content,blplocus activity (P= 0.798), and inhibitory phenotype (P= 0.716). In addition, no significant differences were observed when single and cocolonizing strains were compared. Despite clear evidence ofblp-mediated competition in experimental models, the results of our study suggest that theblplocus plays a limited role in restricting pneumococcal cocolonization in humans.IMPORTANCENasopharyngeal colonization with Streptococcus pneumoniae (pneumococcus) is important for pneumococcal evolution, as the nasopharynx represents the major site for horizontal gene transfer when multiple strains co-occur, a phenomenon known as cocolonization. Understanding how pneumococcal strains interact within the competitive environment of the nasopharynx is of chief importance in the context of pneumococcal ecology. In this study, we used an unbiased collection of naturally co-occurring pneumococcal strains and showed that a biological process frequently used by bacteria for competition—bacteriocin production—is not decisive in the coexistence of pneumococci in the host, in contrast to what has been shown in experimental models.