Modifiable Risk Factors for the Emergence of Resistance to Pseudomonas aeruginosa

项目摘要 碳青霉烯类耐药铜绿假单胞菌（CR-P. aeruginosa）可导致 住院病人。在美国，只有四种β-内酰胺类药物具有抗CR-P. aeruginosa的活性， 其中头孢洛扎-他唑巴坦（C-T）最常用于治疗CR-P. aeruginosa。临床前 研究表明C-T对>90%的铜绿假单胞菌分离株具有活性; 最初测试对C-T敏感但在治疗期间变得耐药的铜绿假单胞菌出现。 我们的初步数据表明，在28例连续感染CR-P.铜绿假单胞菌的患者中， 最初对C-T敏感的分离株，50%的患者随后有> 4倍的铜绿假单胞菌分离株 C-T暴露后30天内C-T最低抑制浓度（MIC）增加。我们确定 通过全基因组测序（WGS）促进抗性的遗传标记-特别是 ampC-ampR区域和PBP 3中。令人担忧的是，86%的铜绿假单胞菌分离株最初对另一种 新型抗生素头孢他啶-阿维巴坦（C-A）在C-T暴露后表现出对C-A的耐药性-在不存在 暴露于C-A。这是令人担忧的，因为对一种新药物的耐药性的出现可能会消除少数几种药物。 剩下的治疗方案。我们探讨了可改变的风险因素，这些因素可能会降低C-T的频率。 结果发现，接受C-T治疗超过1小时的患者中，有30%随后出现C-T耐药 然而，接受药物超过3小时的患者没有产生耐药菌株。我们想 重复这项探索性工作，并在260名患者的队列中进行实验验证研究， 七家医院将配对的铜绿假单胞菌临床分离株储存在-80 ° C下，并开具C-T处方。 在目标1中，WGS将鉴定与C-T抗性相关的遗传位点， C-T暴露前和暴露后30天内来自同一患者的分离株。验证将通过 克隆和定点突变工作。肉汤微量稀释法将确定以下药物的敏感性试验结果： 对CR-P. aeruginosa具有活性的其他三种β-内酰胺，以量化交叉耐药性的出现。 在目标2中，我们将在参与研究中心利用不同的C-T管理策略， 机器学习衍生的决策树，告知临床医生如何最有效地开C-T处方，以减少 获得性抵抗的可能性。以下是一些风险因素，将调查潜在的 包括：（1）C-T输注超过3小时，（2）大剂量C-T，（3）联合抗生素治疗，（4）透析 （5）传染源和传染源控制;（6）接触C-T天数。 这项工作将（1）通过高度识别细菌染色体的区域来告知未来的药物开发 容易产生阻力，需要额外的加强和（2）确定可以改变的风险因素， 临床医生使用，使新的抗生素保持有效的治疗选择，延长时间。

Project Summary Carbapenem-resistant Pseudomonas aeruginosa (CR-P. aeruginosa) contributes to significant mortality in hospitalized patients. Only four β-lactam agents with activity against CR-P. aeruginosa are available in the US, of which ceftolozane-tazobactam (C-T) is the most frequently used to treat CR-P. aeruginosa. Pre-clinical investigations indicate C-T had activity against >90% of P. aeruginosa isolates; after clinical use, reports of P. aeruginosa that initially tested susceptible to C-T but became resistant during therapy emerged. Our preliminary data indicate that amongst 28 consecutive patients infected with CR-P. aeruginosa with isolates initially susceptible to C-T, 50% of patients had subsequent P. aeruginosa isolates with > 4-fold increase in C-T minimum inhibitory concentrations (MICs) up to 30 days after C-T exposure. We identified genetic markers contributing to resistance through whole genome sequencing (WGS) – notably mutations in the ampC-ampR region and in PBP3. Alarmingly, 86% of P. aeruginosa isolates initially susceptible to another novel antibiotic, ceftazidime-avibactam (C-A), exhibited resistance to C-A after C-T exposure - in the absence of C-A exposure. This is concerning as the emergence of resistance to one novel agent could eliminate the few remaining treatment options. We explored modifiable risk factors that could reduce the frequency of C-T resistance and found that 30% of patients who received C-T over 1 hour had subsequent C-T resistant isolates, whereas no patients who received the drug over 3 hours developed resistant isolates. We would like to repeat this exploratory work and include experimental validation studies in a cohort of 260 patients across seven hospitals who have paired P. aeruginosa clinical isolates stored at -80°C and were prescribed C-T. In Aim 1, WGS will identify the genetic loci associated with C-T resistance comparing paired CR-P. aeruginosa isolates from the same patient before and up to 30 days after C-T exposure. Validation will occur through cloning and site-directed mutagenesis work. Broth microdilution will determine susceptibility testing results for the three other β-lactams with activity against CR-P. aeruginosa to quantify the emergence of cross-resistance. In Aim 2, we will capitalize on diverse C-T administration strategies at participating sites and develop a machine learning derived decision tree to inform clinicians how to prescribe C-T most effectively to reduce the likelihood of acquired resistance. The following are some risk factors that will be investigated for potential inclusion: (1) infusion of C-T over 3 hours, (2) high-dose C-T, (3) combination antibiotic therapy, (4) dialysis dependency, (5) source of infection and source control, (6) number of days of C-T exposure. This work will (1) inform future drug development by identifying areas of the bacterial chromosome highly prone to resistance and in need of additional reinforcement and (2) identify modifiable risk factors that can be used by clinicians to enable novel antibiotics to remain effective treatment options for extended periods of time.