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: 8396810
• 负责人: Matthew Ramsey
• 金额: $ 4.71万
• 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 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8396810
• 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. PUBLIC HEALTH RELEVANCE: Vancomycin resistance has transferred de novo from vancomycin resistant enterococci (VRE) into methicillin resistant S. aureus (MRSA) at least 12 times during the course of infection, resulting in VRSA. The emergence of vancomycin resistance in S. aureus compromises a key last line bactericidal drug for treating a very common cause of invasive bacterial infection. I will identify and characterize factors that contribute to he spread of vancomycin resistance into S. aureus, with the goal of developing new strategies for its containment. Vancomycin resistance is not yet firmly established in MRSA, and the results generated may lead to strategies to preserve the utility of an important last line drug.

性状（由申请方提供）：耐甲氧西林沙门氏菌。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MRSA质粒上，形成VRSA。在感染过程中，这种情况至少发生了12次，主要发生在糖尿病患者四肢的病变中。所有鼠伤寒沙门万古霉素抗性转座子的金黄色葡萄球菌受体是单一的S. aureus clade，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，以便发生转移。我推测，CC 5 MRSA和VRE表现出独特的相互作用相比，其他MRSA谱系，其中包括合作代谢能力，促进协同作用，与宿主衍生因子的共聚集，以及种内和种间细胞信号转导的调制。初步数据确定血清依赖性共聚集是CC 5-MRSA和VRE对所特有的。为了确定影响多物种结合的因素，将纯化血清组分加入共培养物中，并通过显微镜和光密度测定共聚集。水平传播的任何增强将通过与含有耐药质粒的肠球菌共培养后选择性接种MRSA受体来定量。我已经发现了下调VRE基因的信息素信号和fsr毒力操纵子的转录组反应的VRE /MRSA在共培养。细胞信号调制的影响将通过转录组学和我们的微阵列数据揭示的推定信息素信号的靶向诱变来研究。D-乳酸（dLac）通常由S.金黄色葡萄球菌。dLac也是VanA型万古霉素耐药性所必需的。由于只有在万古霉素存在时才能诱导VanA型耐药，我推测S.金黄色葡萄球菌dLac的产生可能为VRE与S.金黄色。这将通过测量万古霉素暴露后共培养物和单一培养物中两种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ST 5-MRSA和VRE特异性的多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。 公共卫生相关性：万古霉素耐药性已从万古霉素耐药肠球菌（VRE）重新转移到甲氧西林耐药链球菌。金黄色葡萄球菌（MRSA）在感染过程中至少12次，导致VRSA。S.金黄色葡萄球菌损害了用于治疗侵入性细菌感染的非常常见原因的关键的最后一线杀菌药物。我将确定和描述导致万古霉素耐药传播到沙门氏菌的因素。金黄色葡萄球菌，其目标是制定新的战略，其遏制。万古霉素耐药性尚未在MRSA中确立，产生的结果可能导致保留重要的最后一线药物效用的策略。