Streptococcus pneumoniae biofilm formation is strain dependent, multifactorial, and associated with reduced invasiveness and immunoreactivity during colonization.
Streptococcus pneumoniae biofilm formation is strain dependent, multifactorial, and associated with reduced invasiveness and immunoreactivity during colonization.
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DOI：
10.1128/mbio.00745-13
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发表时间：
2013-10-15
期刊：
影响因子：
6.4
通讯作者：
Orihuela CJ
中科院分区：
文献类型：
--
作者：
Blanchette-Cain K;Hinojosa CA;Akula Suresh Babu R;Lizcano A;Gonzalez-Juarbe N;Munoz-Almagro C;Sanchez CJ;Bergman MA;Orihuela CJ
生物膜被认为在肺炎链球菌在鼻咽部的定殖过程中起重要作用，但它们在体内如何形成以及负责的决定因素仍然未知。使用扫描电子显微镜，我们表明，生物膜聚集体的复杂性增加，形成小鼠鼻隔鼻内接种。这些生物膜与体外生物膜高度不同，因为它们是不连续的，并且似乎包含非细菌组分，例如完整的宿主细胞。生物膜最初形成于纤毛上皮细胞的表面，随着细胞脱落，在基底膜上被发现。对鼻灌洗液中生物膜聚集体的大小和数量进行数字定量，并揭示了与形成稳健的体外生物膜的能力松散相关的菌株特异性能力。我们测试了CbpA、肺炎球菌溶血素、过氧化氢、LytA、LuxS、CiaR/H和PsrP缺陷的同基因突变体在鼻咽内形成生物膜的能力。该分析表明，CiaR/H是绝对需要的殖民化，PsrP和SpxB强烈影响聚集体的形成，和其他决定因素影响聚集体形态在一个温和的方式。我们确定，与野生型对照组相比，ΔpsrP突变体定殖的小鼠鼻灌洗液中促炎细胞因子肿瘤坏死因子α（TNF-α）、白细胞介素-6（IL-6）、IL-1β和KC的水平更高。这种表型与生物膜肺炎球菌在体外侵入宿主细胞的能力减弱相关，尽管附着增强。我们的研究结果表明，生物膜形成殖民过程中，并表明，他们可能有助于持久性通过一个超粘附，非侵入性的状态，eleventa抑制细胞因子的反应。这项工作证明了肺炎链球菌生物膜形成在体内的第一个时间表征。我们的研究结果表明，侵入性和非侵入性的临床分离株在体内形成的生物膜的形态是不同的，在体外形成的生物膜，但倾向于在体内形成生物膜松散相关的程度在微量滴定板上的体外生物膜形成。我们表明，宿主成分，包括完整的宿主细胞，影响体内结构的形成。我们还发现，体内有效的生物膜形成需要多种细菌决定簇。虽然一些因子对于体内生物膜形成是必需的（CiaRH、PsrP和SpxB），但其他因子不太重要（CbpA、LytA、LuxS和肺炎球菌溶血素）。与它们的促炎性对应物相比，生物膜肺炎球菌是高度粘附的，但侵袭性较小，并且引起较弱的促炎性细胞因子反应。这些发现提供了深入了解的要求和潜在的作用，生物膜在长期无症状的殖民。
Biofilms are thought to play an important role during colonization of the nasopharynx by Streptococcus pneumoniae, yet how they form in vivo and the determinants responsible remain unknown. Using scanning electron microscopy, we show that biofilm aggregates of increasing complexity form on murine nasal septa following intranasal inoculation. These biofilms were highly distinct from in vitro biofilms, as they were discontiguous and appeared to incorporate nonbacterial components such as intact host cells. Biofilms initially formed on the surface of ciliated epithelial cells and, as cells were sloughed off, were found on the basement membrane. The size and number of biofilm aggregates within nasal lavage fluid were digitally quantitated and revealed strain-specific capabilities that loosely correlated with the ability to form robust in vitro biofilms. We tested the ability of isogenic mutants deficient in CbpA, pneumolysin, hydrogen peroxide, LytA, LuxS, CiaR/H, and PsrP to form biofilms within the nasopharynx. This analysis revealed that CiaR/H was absolutely required for colonization, that PsrP and SpxB strongly impacted aggregate formation, and that other determinants affected aggregate morphology in a modest fashion. We determined that mice colonized with ΔpsrP mutants had greater levels of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-1β, and KC in nasal lavage fluid than did mice colonized with wild-type controls. This phenotype correlated with a diminished capacity of biofilm pneumococci to invade host cells in vitro despite enhanced attachment. Our results show that biofilms form during colonization and suggest that they may contribute to persistence through a hyperadhesive, noninvasive state that elicits a dampened cytokine response. This work demonstrates the first temporal characterization of Streptococcus pneumoniae biofilm formation in vivo. Our results show that the morphology of biofilms formed by both invasive and noninvasive clinical isolates in vivo is distinct from that of formed biofilms in vitro, yet propensity to form biofilms in vivo loosely correlates with the degree of in vitro biofilm formation on a microtiter plate. We show that host components, including intact host cells, influence the formation of in vivo structures. We also found that efficient biofilm formation in vivo requires multiple bacterial determinants. While some factors are essential for in vivo biofilm formation (CiaRH, PsrP, and SpxB), other factors are less critical (CbpA, LytA, LuxS, and pneumolysin). In comparison to their planktonic counterparts, biofilm pneumococci are hyperadhesive but less invasive and elicit a weaker proinflammatory cytokine response. These findings give insight into the requirements for and potential role of biofilms during prolonged asymptomatic colonization.