RESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Among the most urgent public health threats is the worldwide emergence of carbapenem-resistant Enterobacteriaceae1-4, which are resistant to the antibiotic class of 'last resort'. In the United States and Europe, carbapenem-resistant strains of the Klebsiella pneumoniae ST258 (ref. 5) sequence type are dominant, endemic6-8 and associated with high mortality6,9,10. We report the global evolution of pathogenicity in carbapenem-resistant K. pneumoniae, resulting in the repeated convergence of virulence and carbapenem resistance in the United States and Europe, dating back to as early as 2009. We demonstrate that K. pneumoniae can enhance its pathogenicity by adopting two opposing infection programs through easily acquired gain- and loss-of-function mutations. Single-nucleotide polymorphisms in the capsule biosynthesis gene wzc lead to hypercapsule production, which confers phagocytosis resistance, enhanced dissemination and increased mortality in animal models. In contrast, mutations disrupting capsule biosynthesis genes impair capsule production, which enhances epithelial cell invasion, in vitro biofilm formation and persistence in urinary tract infections. These two types of capsule mutants have emerged repeatedly and independently in Europe and the United States, with hypercapsule mutants associated with bloodstream infections and capsule-deficient mutants associated with urinary tract infections. In the latter case, drug-tolerant K. pneumoniae can persist to yield potentially untreatable, persistent infection.
Assuntos
Adaptação Biológica/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Evolução Molecular , Klebsiella pneumoniae/genética , Virulência/genética , Resistência beta-Lactâmica/genética , Adulto , Animais , Cápsulas Bacterianas/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/classificação , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Enterobacteriáceas Resistentes a Carbapenêmicos/patogenicidade , Carbapenêmicos/uso terapêutico , Células Cultivadas , Feminino , Genoma Bacteriano , Humanos , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/urina , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/patogenicidade , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Transgênicos , Filogenia , Polimorfismo de Nucleotídeo Único , Infecções Urinárias/microbiologia , Infecções Urinárias/urina , Peixe-ZebraRESUMO
Compartmentalization of metabolism into specific regions of the cell, tissue, and organ is critical to life for all organisms. Mass spectrometric imaging techniques have been valuable in identifying and quantifying concentrations of metabolites in specific locations of cells and tissues, but a true understanding of metabolism requires measurement of metabolite flux on a spatially resolved basis. Here, we utilize desorption ESI-MS (DESI-MS) to measure lipid turnover in the brains of mice. We show that anatomically distinct regions of the brain have distinct lipid turnover rates. These turnover measurements, in conjunction with relative concentration, will enable calculation of regiospecific synthesis rates for individual lipid species in vivo. Monitoring spatially dependent changes in metabolism has the potential to significantly facilitate research in many areas, such as brain development, cancer, and neurodegeneration.
