Urovirulence and fimbrial regulation in Klebsiella quasipneumoniae

准肺炎克雷伯菌的尿毒力和菌毛调节

• 批准号: 10742629
• 负责人: Nicole Janell De Nisco
• 金额: $ 25.27万
• 依托单位: UNIVERSITY OF TEXAS DALLAS
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-18 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10742629
• 关键词: Acute; Acute Cystitis; Adult; Affect; Age; Animal Model; Antibiotic Resistance; Antimicrobial Resistance; Bacteria; Bacterial Adhesion; Bacterial Infections; Benchmarking; Binding; Biological Assay; Bladder; C-terminal; C3H/HeN Mouse; Clinical; Confocal Microscopy; Cystitis; DNA Binding Domain; Enterobacteriaceae; Epithelial Cells; Epithelium; Escherichia coli; Exhibits; Genes; Genome; Genomics; Gentamicins; Goals; Health; Hour; Human; Hybrids; In Vitro; Infection; Infective cystitis; Invaded; Kidney; Klebsiella; Klebsiella pneumoniae; Knowledge; Lung; Measurement; Measures; Mediating; Menopausal Status; Metabolic; Metadata; Methods; Mining; Mobile Genetic Elements; Modeling; Multi-Drug Resistance; Mus; N-terminal; Nucleic Acid Regulatory Sequences; Operon; Patients; Periodicity; Persons; Phenotype; Play; Prevalence; Publishing; Quality of life; Recurrence; Regulation; Role; Sequence Alignment; Sequence Analysis; Site; Structure; Surface; Surgical Wound Infection; System; Urethra; Urinary tract; Urinary tract infection; Urine; Uropathogen; Uropathogenic E. coli; Virulence; Virulence Factors; Woman; Work; bacterial community; biobank; defined contribution; experience; genome sequencing; human disease; human pathogen; mouse model; nanopore; phosphoric diester hydrolase; resistance gene; type 1 fimbriae; urovirulent isolates; whole genome

Project Summary Urinary tract infection (UTI) and recurrent UTI (rUTI) significantly reduces the quality of life of millions of women annually and poses a growing health threat due to the increasing prevalence of antibiotic resistant uropathogenic bacteria. Klebsiella spp. represent the second most common bacterial species isolated from the urine of women experiencing rUTI but have been largely understudied in the context of rUTI. Within the Klebsiella genus, Klebsiella pneumoniae is one of the most common human pathogens; however, genome sequence analysis has revealed that that K. pneumoniae isolates encompass at least three distinct species: K. pneumoniae, K. variicola and K. quasipneumoniae. Although K. quasipneumoniae strains are commonly isolated from patients with UTI and encode known virulence factors and antimicrobial resistance genes, no study has evaluated urovirulence phenotypes of K. quasipneumoniae in an animal model. Indeed, the clinical prevalence of K. quasipneumoniae in UTI remains unknown. Among the virulence factors that Klebsiella spp. possess, type 1 (fim operon) and type 3 (mrk operon) fimbriae play a crucial role in mediating bacterial adhesion and invasion of host epithelial surfaces. Type 1 fimbriae are widely conserved among Enterobacteriaceae, but the presence of the gene fimK differentiates the fim operons of Klebsiella spp. from Escherichia coli. In K. pneumoniae, FimK is a regulator of fim operon expression and is comprised of an N-terminal DNA binding domain that binds the fimS regulatory region and a conserved C-terminal EAL domain with phosphodiesterase activity. Through sequence alignment of the fim operons of sequenced K. quasipneumoniae and K. pneumoniae isolates, we have discovered that the fimK gene of K. quasipneumoniae is truncated and lacks the C-terminal EAL domain. This is important because not only is fimK a key regulator of fim operon expression, but it is also proposed to co-regulate mrk operon expression by modulation of cyclic di-GMP levels through its phosphodiesterase activity. We have found that FimK-mediated regulation of type 1 and type 3 fimbriae is distinct in K. quasipneumoniae due to the absence of the FimK EAL domain. We hypothesize that because of this regulatory difference, bladder infection dynamics and the requirement for type 1 versus type 3 fimbriae for bladder colonization may be distinct in K. quasipneumoniae. This proposal will address these hypotheses and produce foundational knowledge of K. quasipneumoniae bladder infection dynamics by i) defining the clinical prevalence of K. quasipneumoniae in UTI in women, ii) evaluating K. quasipneumoniae rUTI isolates in a mouse model of acute UTI, and iii) evaluating the role of K. quasipneumoniae type 1 versus type 3 fimbriae and FimK during acute UTI. Taken together, this work will produce the first foundational knowledge of clinical prevalence and bladder infection dynamics of the understudied human uropathogen K. quasipneumoniae and define the impact of the conserved truncation of the fimbrial regulator FimK on the regulation of type 1 and type 3 fimbriae and bladder colonization.

项目摘要 尿路感染(UTI)和复发性尿路感染(RUTI)显著降低了数百万人的生活质量 由于抗生素耐药性的增加，对妇女的健康构成了越来越大的威胁 泌尿系致病菌。克雷伯氏菌代表第二种最常见的细菌种类，分离自 在Ruti的背景下，对经历Ruti的妇女的尿液进行了很大程度上的研究不足。在克雷伯氏菌中 肺炎克雷伯菌属是人类最常见的病原体之一；然而，基因组序列 分析表明，肺炎克雷伯菌分离株至少包括三个不同的种类：K. 肺炎克雷伯菌、花斑克雷伯氏菌和拟肺炎克雷伯氏菌。虽然准肺炎克雷伯菌菌株通常是分离出来的 来自尿路感染患者，并编码已知的毒力因子和抗菌素耐药基因，目前还没有研究 在动物模型中评估拟肺炎克雷伯菌的尿毒力表型。事实上，临床流行率 准肺炎克雷伯菌在尿路感染中的感染情况尚不清楚。 在克雷伯氏菌的毒力因子中，Klebsiella spp.拥有，类型1(fim操纵子)和类型3(mrk操纵子) 菌毛在介导细菌对宿主上皮细胞表面的黏附和侵袭中起着至关重要的作用。类型1 菌毛在肠杆菌科中广泛保守，但fimK基因的存在区分了 克雷伯氏菌的FIM操纵子。从大肠杆菌中分离出来。在肺炎克雷伯菌中，FimK是fim操纵子的调节因子。 它由结合FIMS调节区的N-末端DNA结合域和 保守的具有磷酸二酯酶活性的C-末端EAL结构域。通过FIM的序列比对 对测序的准肺炎克雷伯菌和肺炎克雷伯菌的操纵子，我们发现fimK基因 准肺炎克雷伯菌的EAL结构域被截短，并且缺少EAL结构域。这一点很重要，因为不仅是 FIMK是FIM操纵子表达的关键调节因子，但也被认为通过以下方式共同调节MRK操纵子的表达 通过其磷酸二酯酶活性调节环状双GMP水平。我们发现FimK介导的 由于缺乏FimK EAL，准肺炎克雷伯菌对1型和3型菌毛的调节明显不同 域。我们假设，由于这种调节差异，膀胱感染动力学和 准肺炎克雷伯菌对膀胱定植的1型菌毛和3型菌毛的需求可能不同。 这项提议将解决这些假设，并产生关于K。 准肺炎克雷伯菌膀胱感染动力学研究：I)确定泌尿系感染中准肺炎克雷伯菌的临床流行 在女性中，ii)在急性尿路感染的小鼠模型中评估准肺炎克雷伯菌分离株，以及iii)评估 准肺炎克雷伯菌1型与3型菌毛和FimK在急性尿路感染中的作用。总而言之，这是 这项工作将产生临床流行率和膀胱感染动力学的第一个基础知识。 未被充分研究的人类泌尿系统病原体准肺炎克雷伯氏菌，并定义保守截断的影响。 研究菌毛调节因子FimK对1型和3型菌毛和膀胱定植的调节作用。