Candida albicans and Staphylococcus aureus dual species biofilms

描述(申请人提供)：金黄色葡萄球菌和人类真菌病原体白色念珠菌是血液和医院获得性感染的主要病原体。由这些不同的微生物引起的大多数感染都与生物膜有关，因为它们能够附着在各种表面上，导致持续和慢性感染。更重要的是，白色念珠菌和金黄色葡萄球菌经常从伤口、粘膜表面和宿主的不同部位共分离出来。尽管它们的流行率和它们在宿主中共存的临床推论，但在多菌感染的背景下探索它们相互作用的含义的研究一直缺乏。基于大量的体外和体内研究的初步发现，这一建议是为了验证这样的假设，即这些微生物在宿主中相互作用，因为它们共存于粘膜表面，对它们的致病潜力和感染过程产生重大影响。具体地说，使用这两个物种的临床菌株，这项建议的目的是证明感染协同作用和侵袭性系统性葡萄球菌感染由白色念珠菌和金黄色葡萄球菌双重物种生物膜引起。为此，我们建立了一种小鼠口腔黏膜混合感染模型，以确定高侵袭性白念珠菌菌丝侵入小鼠口腔黏膜是否会导致金黄色葡萄球菌的全身感染，这种金黄色葡萄球菌通常是非侵袭性的，但却是可躲避的。此外，由于初步数据似乎暗示双物种生物膜诱导的蛋白质表达参与了动物模型中的联合感染过程，因此计划进行全球蛋白质表达分析，以描述特定毒力因子的表达。随后，鉴定出的蛋白质对毒力增强的直接作用将通过基因敲除研究来阐明。综上所述，这些新的初步发现需要进一步深入研究白色念珠菌和金黄色葡萄球菌之间复杂的相互作用，因为这些常见病原体经常合并感染危重住院患者，导致显著的发病率和死亡率。我们期望这项提议的目标的实现将成为促进真菌-细菌相互作用和一般多菌疾病领域的范例。更重要的是，所产生的研究结果的传播将有助于设计新的治疗战略，旨在抗击真菌-细菌多菌感染。 公共卫生相关性：金黄色葡萄球菌和人类真菌病原体白色念珠菌能够附着在各种表面，导致严重的慢性生物被膜相关感染。这些微生物也是从感染患者的不同部位一起分离出来的。然而，尽管它们的流行率和发病机制都很普遍，但在多菌或混合感染的背景下探索它们相互作用的含义的研究一直很少。为此，使用小鼠感染模型，我们进行了广泛的初步研究，证明了当这些微生物共存于宿主中时，它们的毒力增强。在这项应用中，我们建议进行更深入的分子和动物研究，以确认我们的初步发现并产生数据，有助于我们理解导致多微生物感染的机制。我们期待这项工作的完成所产生的发现将有助于设计新的治疗策略来对抗多菌感染。

DESCRIPTION (provided by applicant): The bacterial species Staphylococcus aureus and the human fungal pathogen Candida albicans are among the leading pathogens in bloodstream and hospital-acquired infections. Most infections caused by these diverse organisms are biofilm-associated due to their ability to adhere to a variety of surfaces causing persistent and chronic infections. More importantly, C. albicans and S. aureus are often co-isolated from wounds, mucosal surfaces and various sites in the host. Despite their prevalence and the clinical inferences of their co-existence in a host, studies exploring the implications of their interaction within the context of polymicrobial infections have been lacking. Based on extensive preliminary findings from in vitro and in vivo studies, this proposal was formulated to validate the hypothesis that these organisms interact in the host as they co-exist on mucosal surfaces with significant impact on their pathogenic potential and the infectious process. Specifically, using clinical strains of both species, this proposal aims to demonstrate infectious synergism and invasive systemic staphylococcal infection due to C. albicans and S. aureus dual species biofilms. To that end, a murine model of oral mucosal co-infection was developed in order to determine whether the penetration of the mouse oral mucosa by the highly invasive C. albicans hyphae leads to systemic infection by the normally non-invasive yet evasive S. aureus. In addition, as preliminary data seem to implicate the involvement of dual-species biofilm-induced protein expression in the co-infectious process in the animal model, global protein expression analyses are planned in order to profile the expression of specific virulence factors. Subsequently, the direct effect of the identified proteins on virulence enhancement will be elucidated using gene knockout studies. Combined, these novel preliminary findings warrant further in depth investigations into the intricate interaction between C. albicans and S. aureus as these common pathogens frequently co-infect critically-ill hospitalized patients causing significant morbidity and mortality. We expect the fulfillment of the aims of this proposal to serve as a paradigm to further the field of fungal- bacterial interactions and polymicrobial diseases in general. More importantly, the dissemination of the findings generated will aid in the design of novel therapeutic strategies aimed at combating fungal-bacterial polymicrobial infections. PUBLIC HEALTH RELEVANCE: The bacterial species Staphylococcus aureus and the human fungal pathogen Candida albicans are capable of adhering on a variety of surfaces causing significant chronic biofilm-associated infections. These microbial species are also isolated together from various sites from infected patients. Yet despite their prevalence and pathogenesis, studies exploring the implications of their interaction within the context of polymicrobial or mixed infections have been lacking. To that end, using a mouse model of infection, we performed extensive preliminary studies which demonstrated enhanced virulence for these organisms when they co-exist in a host. In this application, we propose to perform additional in depth molecular and animal studies in order to confirm our preliminary findings and generate data to contribute to our understanding of the mechanisms leading to multi-microbial infections. We expect the findings generated from the accomplishment of this work to aid in the design of novel therapeutic strategies to combat polymicrobial infections.