Polymicrobial dynamics in transfer of vancomycin resistance to MRSA

万古霉素耐药性向 MRSA 转移的多微生物动力学

• 批准号: 8519048
• 负责人: Matthew Ramsey
• 金额: $ 0.41万
• 依托单位: MASSACHUSETTS EYE AND EAR INFIRMARY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2013-07-05
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8519048
• 关键词: Affect; Antibiotic Resistance; Bacterial Infections; Binding; Biological Assay; Cell Wall; Cells; Coculture Techniques; Code; Communication; Containment; DNA; Data; Detection; Down-Regulation; Enterococcus; Enterococcus faecalis; Environment; Exhibits; Fermentation; Gene Expression Profile; Genes; Goals; Horizontal Disease Transmission; Horizontal Gene Transfer; In Situ; In Vitro; Incubated; Infection; Integration Host Factors; Lead; Lesion; Limb structure; Measures; Mediating; Metabolic; Metabolism; Microbial Biofilms; Microscopy; Mono-S; Mutagenesis; Nature; Nutrient; Oligopeptides; Operon; Optics; Partner in relationship; Peptidoglycan; Pharmaceutical Preparations; Phenotype; Pheromone; Physiology; Plasmids; Positioning Attribute; Production; Proteins; Repression; Research; Resistance; Role; ST5 gene; Serum; Signal Pathway; Signal Transduction; Site; Staphylococcus aureus; Testing; Time; Vancomycin; Vancomycin Resistance; Vancomycin resistant enterococcus; Vancomycin-resistant S. aureus; Virulence; Virulent; bactericide; density; diabetic; in vivo; loss of function; methicillin resistant Staphylococcus aureus; mutant; response; stem; transcriptomics

DESCRIPTION (provided by applicant): Methicillin resistant S. aureus (MRSA) are leading causes of antibiotic resistant infection, treated mainly with vancomycin. Since 2002, VanA-type vancomycin resistance has moved on plasmids from vancomycin resistant enterococci (VRE) to MRSA, forming VRSA. This has happened at least 12 times independently during the course of infection, mainly in lesions on the extremities of diabetics. All S. aureus recipients of the vancomycin resistance transposon have been of a single S. aureus clade, CC5. For horizontal transmission to occur, VRE and MRSA must occupy the same environment in sufficient number and proximity for transfer to occur. I hypothesize that CC5 MRSA and VRE exhibit unique interactions compared to other MRSA lineages, which include cooperative metabolic abilities promoting synergy, co-aggregation with host-derived factors, and modulation of intra- and interspecies cell signaling. Preliminary data identified serum-dependent co-aggregation as being unique to CC5-MRSA and VRE pairs. To determine what affects multi-species binding, purified serum components will be added to co-cultures and co-aggregation will be assayed by microscopy and optical density. Any enhancement of horizontal transmission will be quantified by selective plating of MRSA recipients after co-culture with enterococci containing a resistance plasmid. I have found down-regulation of VRE genes for pheromone signaling and the fsr virulence operon in the transcriptome responses of VRE /MRSA in co-culture. The impact of cell signaling modulation will be studied by transcriptomics and targeted mutagenesis of the putative pheromone signal revealed by our microarray data. D-lactate (dLac) is commonly produced by S. aureus during fermentation. dLac is also necessary for VanA-type vancomycin resistance. As VanA type resistance is induced only when vancomycin is present, I hypothesize that S. aureus dLac production may provide an advantage to VRE in co-culture with S. aureus. This will be tested by measuring survival of both species in co- and mono-culture after vancomycin exposure as well as VRE in mono-culture incubated with dLac prior to vancomycin treatment. These results will ultimately reveal the nature of polymicrobial interactions specific to ST5-MRSA and VRE and how they lead to vancomycin resistance transfer.

描述（由申请人提供）：耐甲氧西林金黄色葡萄球菌（MRSA）是抗生素耐药性感染的主要原因，主要用万古霉素治疗。自2002年以来，VanA型万古霉素耐药性已从万古霉素耐药肠球菌（VRE）转移到质粒上，形成MRSA，形成VRSA。这种情况在感染过程中至少独立发生过12次，主要发生在糖尿病患者四肢的病变部位。万古霉素抗性转座子的所有金黄色葡萄球菌受体均属于单一金黄色葡萄球菌进化枝CC5。为了发生水平传播，VRE 和 MRSA 必须以足够的数量和距离占据相同的环境，才能发生传播。我假设与其他 MRSA 谱系相比，CC5 MRSA 和 VRE 表现出独特的相互作用，其中包括促进协同作用的协作代谢能力、与宿主衍生因子的共聚集以及物种内和物种间细胞信号传导的调节。初步数据表明，血清依赖性共聚集是 CC5-MRSA 和 VRE 对所独有的。为了确定影响多物种结合的因素，将纯化的血清成分添加到共培养物中，并通过显微镜和光密度分析共聚集。与含有抗性质粒的肠球菌共培养后，通过选择性平板接种 MRSA 受体来量化水平传播的任何增强。我发现在共培养的 VRE /MRSA 转录组反应中，信息素信号传导的 VRE 基因和 fsr 毒力操纵子的下调。细胞信号调节的影响将通过转录组学和我们的微阵列数据揭示的假定信息素信号的定向诱变来研究。 D-乳酸 (dLac) 通常由金黄色葡萄球菌在发酵过程中产生。 dLac 对于 VanA 型万古霉素耐药性也是必需的。由于仅当万古霉素存在时才会诱导 VanA 型耐药性，因此我推测金黄色葡萄球菌 dLac 的产生可能为与金黄色葡萄球菌共培养的 VRE 提供优势。这将通过测量万古霉素暴露后共培养和单一培养物中两个物种的存活率以及万古霉素处理前与 dLac 孵育的单一培养物中的 VRE 来进行测试。这些结果将最终揭示 ST5-MRSA 和 VRE 特有的多种微生物相互作用的性质，以及它们如何导致万古霉素耐药性转移。