Disappearance of rifampin resistance in MRSA foreign body osteomyelitis

MRSA异物骨髓炎利福平耐药性消失

• 批准号: 9165887
• 负责人: Robin Patel
• 金额: $ 19.88万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9165887
• 关键词: Affect; Animal Model; Animals; Antibiotics; Bacteria; Base Pairing; Clinical Treatment; Combined Modality Therapy; Data; Debridement; Disadvantaged; Ensure; Evolution; Experimental Models; Exposure to; Foreign Bodies; Frequencies; Future; Gene Targeting; Genes; Genomics; Genus staphylococcus; Implant; In Vitro; Infection; Joint Prosthesis; Kinetics; Mediating; Medical Technology; Microbial Biofilms; Modeling; Monitor; Mutation; Operative Surgical Procedures; Orthopedics; Osteomyelitis; Outcome; Patients; Pharmaceutical Preparations; Play; Population; Rattus; Regimen; Resistance; Rifampicin resistance; Rifampin; Rifamycins; Role; Sampling; Site; Staphylococcus aureus; Staphylococcus epidermidis; Testing; Time; Treatment Protocols; Treatment outcome; Withholding Treatment; aging population; antimicrobial; antimicrobial drug; base; fitness; genome sequencing; in vivo; joint infection; methicillin resistant Staphylococcus aureus; microbial; microorganism; novel; pathogen; research study; retention rate; time use; whole genome

Project Summary Due to an aging population and advances in medical technology, prosthetic joint placement is increasing in frequency. Prosthetic joint infection (PJI) affects up to 2% of prosthetic joints. Staphylococci are the most common causes of PJI, with Staphylococcus aureus being the most common pathogen overall and Staphylococcus epidermidis being the second most common staphylococcal species involved. Treatment of PJI is problematic due to the limited activity of most antimicrobial agents against microbial biofilms. Rifampin, however, has anti-biofilm activity, and is a cornerstone drug in the management of staphylococcal PJI, when managed with débridement and implant retention (DAIR). Unfortunately, resistance to rifampin, mediated by single base pair mutations in the target gene, is readily selected and would be expected to compromise management of staphylococcal PJI using a DAIR strategy. Our preliminary data surprisingly suggest, however, that selected rifampin resistance may not necessarily negatively impact future treatment using rifampin-based therapy. Specifically, we have shown that, as expected, rifampin resistance is selected following rifampin monotherapy in a rat model of methicillin-resistant S. aureus foreign body osteomyelitis (FBO). But, surprisingly, rifampin resistance “disappears” two weeks following cessation of treatment, with only rifampin susceptible S. aureus being detectable. We have shown that rifampin resistance does not confer decreased fitness when bacteria are grown alone in vitro or in vivo; however, rifampin-resistant bacteria are out-competed by rifampin-susceptible bacteria when grown together in vitro and in vivo. And, when treating FBO with two rounds of rifampin monotherapy, resistance is observed at a lower frequency following the second than the first round of rifampin exposure. These observations suggest that rifampin may be a usable agent in biofilm- associated infections in which rifampin resistance has been previously selected. The central hypothesis of our proposed studies is therefore that in experimental FBO, treatment with rifampin can be successful even if rifampin resistance has been previously selected. Our objectives are to develop an experimental FBO model that allows sampling of bacteria in real time from the same animal and to use the model to define the kinetics of selection and disappearance of rifampin resistance. Whereas in traditional osteomyelitis models, microorganisms are analyzed at single time-points (i.e., when animals are sacrificed), the proposed model will allow analysis of bacteria from the same animal over time. We will perform whole genome sequencing on bacteria recovered at multiple time-points during and following one and two rounds of rifampin treatment. This will allow definition of rifampin resistance- and fitness-associated mutations that emerge during and following initial rifampin treatment, and subsequent re-exposure to rifampin. This approach will pinpoint mutations that may occur in rifampin-susceptible bacteria allowing their persistence or conferring upon them a selective advantage over their rifampin-resistant counterparts, even when challenged with rifampin. Finally, we will compare outcomes of FBO treated with either rifampin monotherapy followed by rifampin combination therapy or rifampin combination therapy alone. This will allow us to determine whether rifampin-containing regimens may be an option in the treatment of PJI in which rifampin resistance has been previously selected. Results of the proposed studies will define the kinetics of in vivo selection of rifampin resistance and identify mutations that play a role in out-competition of rifampin-resistant bacteria by those that are rifampin-susceptible. Additionally, our studies will inform clinical treatment options in the scenario of selected rifampin resistance and lay the groundwork for future experiments defining optimal therapy following selection of rifampin resistance.

项目摘要 由于人口老龄化和医疗技术的进步，假体联合安置正在增加 频率。假体关节感染（PJI）最多影响2％的假体关节。葡萄球菌是最大的 PJI的常见原因，金黄色葡萄球菌是总体上最常见的病原体， 表皮葡萄球菌是涉及第二大最常见的葡萄球菌物种。处理 由于大多数抗菌剂对微生物生物膜的活性有限，因此PJI是有问题的。利福平， 但是，具有抗生物膜活性，并且是葡萄球菌PJI治疗的基石药物，当 通过缩写和植入物保留（DAIR）进行管理。不幸的是，对利福平的抵抗，由 靶基因中的单基对突变很容易选择，并有望妥协 使用DAIR策略对葡萄球菌PJI进行管理。但是，我们的初步数据令人惊讶地表明 选定的利福平耐药性可能不一定会对未来的利福平对未来治疗产生负面影响 疗法。特别是，我们已经表明，正如预期的那样，利福平在利福平之后选择 耐甲氧西林的大鼠模型中的单一疗法抗甲氧西林链球菌异物骨髓炎（FBO）。但， 出乎意料的是，在停止治疗后两周里，利福平耐药性“消失”，仅利福平 检测到敏感的金黄色葡萄球菌。我们已经表明，利福平抗性不会降低 当细菌在体外或体内单独生长时适合；但是，抗利福平的细菌是远远的 在体外和体内一起生长时，可通过利福平敏感细菌。而且，用两个治疗FBO 利福平单一疗法的一轮，第二次在第二个频率之后观察到抗性。 利福平的圆形暴露。这些观察结果表明，利福平可能是生物膜中的可用剂 先前选择了利福平抗性的相关感染。 因此，我们提出的研究的中心假设是在实验FBO中，利福平治疗 即使先前选择了利福平抗性，也可以成功。我们的目标是发展 实验FBO模型，该模型允许从同一动物实时对细菌进行取样并使用 定义利福平耐药性选择和消失动力学的模型。而传统 骨髓炎模型，微生物在单个时间点（即，处死动物时）， 提出的模型将随着时间的推移分析来自同一动物的细菌。我们将表现完整 在一轮和两轮之后以多个时间点恢复的细菌上的基因组测序 利福平治疗。这将允许定义利福平抗性和与健身相关的突变 在初次利福平治疗期间和之后出现，随后重新暴露于利福平。这种方法 将确定可能发生在利福平的细菌中可能发生的突变，以使其持久或会议 在他们身上，即使受到挑战， 利福平。最后，我们将比较用利福平单一疗法治疗的FBO的结果，然后比较 利福平联合疗法或利福平联合疗法。这将使我们能够确定是否 在Rifampin的PJI治疗中，可能是利福平耐药性的一种选择 先前选择的。拟议的研究的结果将定义体内选择利福平的动力学 抗性和识别突变在抗利福平的细菌中发挥作用的突变 是可振兴的。此外，我们的研究将为临床治疗方案提供信息 选定的利福平耐药性，并为未来定义最佳治疗的实验奠定基础 利福平抗性的选择。