Antibiotic resistance among hypermutator carbapenem resistant Klebsiella pneumoniae

超突变碳青霉烯类耐药肺炎克雷伯菌的抗生素耐药性

• 批准号: 10532461
• 负责人: M. Hong Thi NGUYEN
• 金额: $ 26.02万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-21 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10532461
• 关键词: Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacteria; Biological; Ceftazidime; Chronic; Clinical; Clinical Microbiology; DNA; DNA biosynthesis; Data; Defect; Development; Enterobacteriaceae Infections; Exhibits; Future; Gastrointestinal tract structure; Gene Mutation; Genes; Genetic Recombination; Genomics; Horizontal Gene Transfer; Human; In Vitro; Infection; Intravenous; Investigation; Klebsiella pneumoniae; Laboratories; Link; Literature; Mediating; Meropenem; Microbiology; Mismatch Repair; Molecular; Mus; Mutation; Organ; Organ Transplantation; Outcome; Patients; Phenotype; Plasmids; Population; Prospective Studies; Public Health; Resistance; Resistance development; Role; Sampling; Sepsis; Solid; Stress; Survivors; Testing; Tissues; United States; Validation; carbapenem resistance; carbapenem-resistant Enterobacteriaceae; carbapenemase; chronic infection; colistin resistance; effective therapy; emerging antibiotic resistance; environmental change; experimental study; fitness; gastrointestinal; gene repair; genome sequencing; gut colonization; improved; improved outcome; innovation; insight; molecular sequence database; mortality; mouse model; mutant; novel; organ transplant recipient; pathogen; promoter; recurrent infection; repository; resistance gene; resistant Klebsiella pneumoniae; response; screening; stem; success; tool; transmission process; treatment strategy; whole genome

Project Summary Carbapenem resistant Enterobacteriaceae (CRE) are major public health threats. CR-Klebsiella pneumoniae (CRKP) are the most common CRE globally. Treatment of CRKP and other CRE infections with new antibiotics like ceftazidime-avibactam (CZA) and meropenem-vaborbactam (MVB) has improved survival, but recurrent infections are common and emergent resistance is problematic. CRE infections are usually due to strains that colonize the GI tract. Among other bacteria, it is now apparent that GI colonization is caused by a population of closely related, but genetically distinct strains. These strains can exhibit a range of antibiotic resistance and biologic attributes, which are often not appreciated by studying single colonies from microbiologic cultures. In studies of natural bacterial populations, ~1 to 5% of isolates exhibit high spontaneous mutation rates, which may confer selective advantages under environmental stress and increase diversity within the population. Such hypermutation (HM) strains are most prevalent in humans during chronic colonization and recurrent infections, and they most often stem from mutations to DNA mismatch repair (MMR) genes like mutS, mutL or mutH. There are few studies of HM among CRKP or CRE. We believe that HM is under-recognized in these bacteria because studies have not assessed long-term GI colonization, recurrent infections, or populations of strains from clinical samples. In this project, we hypothesize that 1) HM CRKP can be recovered from patients with chronic GI colonization and persistent/recurrent infections; 2) MMR and other gene mutations promote HM in vitro, and CZA and MVB resistance in vitro and within infected organs; and 3) these mutations promote transmission and receipt of antibiotic resistance gene (ARG)-bearing plasmids by CRKP in vitro and during GI colonization. In pilot screening studies, we recovered HM CRKP from ~30% of patients with chronic GI colonization, or persistent or recurrent infections. MMR gene mutations were identified in most HM CRKP strains. One of these mutations (MutH V76G) was proven to contribute to HM, MVB and CZA resistance, and enhanced transfer and acceptance of plasmids containing ARGs in vitro, and to CRKP tissue burdens and emergence of MVB resistance within infected organs of intravenously (IV)-infected mice. In aim 1 of this proposal, we will continue to screen clinical CRKP isolates for HM phenotype. We will perform whole genome sequencing on HM isolates, and create isogenic mutant strains to determine if certain mutations contribute to HM. In aim 2, we will evaluate the role of HM mutations in emergence of CZA, MVB and colistin resistance in vitro and within mouse organs following IV infection. Then, we will determine impact of HM mutations on transfer of ARG-bearing plasmids in vitro and during mouse GI colonization. This project will mark the first systematic investigations of CRE clinical isolates for HM phenotypes. If successful, experiments will provide new understanding of HM and its crucial roles in regulating CRKP antibiotic resistance. Isogenic HM strains created here will also be powerful tools for assessing resistance barriers for novel antibiotics and new targets of antibiotic discovery.

项目摘要 抗碳青霉烯型肠杆菌科（CRE）是主要的公共卫生威胁。 Cr-klebsiella肺炎 （CRKP）是全球最常见的CRE。用新抗生素治疗CRKP和其他CRE感染 像Ceftazidime-avibactam（CZA）和Meropenem-vaborbactam（MVB）的生存率有所提高，但经常性 感染很常见，紧急阻力是有问题的。 CRE感染通常是由于菌株 殖民地胃肠道。在其他细菌中，现在显然是由 密切相关，但遗传上不同的菌株。这些菌株可以表现出一系列抗生素耐药性和 生物学属性通常不会通过研究微生物培养物中的单个菌落来理解。在 天然细菌种群的研究，〜1至5％的分离株表现出高自发突变率，这可能 在环境压力下赋予选择性优势，并增加人口内部的多样性。这样的 在慢性定殖和复发感染期间，超突击（​​HM）菌株在人类中最普遍， 它们通常源自突变到DNA不匹配修复（MMR）基因，例如MUTS，MUTL或Muth。那里 在CRKP或CRE中对HM的研究很少。我们认为，在这些细菌中，HM被低估了，因为 研究尚未评估长期的胃肠道定殖，复发感染或临床菌株种群 样品。在这个项目中，我们假设1）可以从慢性GI患者中回收HM CRKP 定植和持续/复发感染； 2）MMR和其他基因突变在体外促进HM，CZA 体外和感染器官内的MVB耐药性； 3）这些突变促进传播和收据 CRKP在体外和GI定殖过程中通过抗生素耐药性基因（ARG）的质粒。在飞行员中 筛选研究，我们从约30％的慢性GI定殖患者或持续或持续或 复发感染。在大多数HM CRKP菌株中鉴定了MMR基因突变。这些突变之一 （Muth V76G）被证明有助于HM，MVB和CZA耐药性，并增强了转移和接受 在体外含有ARG的质粒，以及CRKP组织负担和MVB耐药性的出现 静脉内感染的器官（IV）感染的小鼠。在本提案的目标1中，我们将继续筛选临床 HM表型的CRKP分离株。我们将对HM分离株进行整个基因组测序，并创建 等生突变菌株以确定某些突变是否有助于HM。在AIM 2中，我们将评估 CZA，MVB和COLISTIN耐药性的HM突变在体外以及小鼠器官内IV后发生 感染。然后，我们将确定HM突变对体外和 在小鼠GI定殖期间。该项目将标志着CRE临床分离株的首次系统研究 用于HM表型。如果成功的话，实验将提供对HM及其至关重要的作用的新理解。 调节CRKP抗生素耐药性。在这里创建的等生HM菌株也将是评估的强大工具 新型抗生素和抗生素发现的新靶标的抗性障碍。