ABSTRACT
An Amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
There is an urgent need for new antibiotics against Gram-negative pathogens that are resistant to carbapenem and third-generation cephalosporins, against which antibiotics of last resort have lost most of their efficacy. Here we describe a class of synthetic antibiotics inspired by scaffolds derived from natural products. These chimeric antibiotics contain a ß-hairpin peptide macrocycle linked to the macrocycle found in the polymyxin and colistin family of natural products. They are bactericidal and have a mechanism of action that involves binding to both lipopolysaccharide and the main component (BamA) of the ß-barrel folding complex (BAM) that is required for the folding and insertion of ß-barrel proteins into the outer membrane of Gram-negative bacteria. Extensively optimized derivatives show potent activity against multidrug-resistant pathogens, including all of the Gram-negative members of the ESKAPE pathogens1. These derivatives also show favourable drug properties and overcome colistin resistance, both in vitro and in vivo. The lead candidate is currently in preclinical toxicology studies that-if successful-will allow progress into clinical studies that have the potential to address life-threatening infections by the Gram-negative pathogens, and thus to resolve a considerable unmet medical need.
Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Drug Resistance, Microbial , Gram-Negative Bacteria/drug effects , Peptidomimetics/chemistry , Peptidomimetics/pharmacology , Animals , Anti-Bacterial Agents/adverse effects , Bacterial Outer Membrane Proteins/chemistry , Bacterial Outer Membrane Proteins/genetics , Biological Products/chemistry , Drug Discovery , Drug Resistance, Microbial/drug effects , Escherichia coli Proteins/chemistry , Escherichia coli Proteins/genetics , Fluorescence , Gram-Negative Bacteria/genetics , Gram-Negative Bacteria/pathogenicity , Humans , Lipopolysaccharides/chemistry , Macrocyclic Compounds/adverse effects , Macrocyclic Compounds/chemistry , Macrocyclic Compounds/pharmacology , Male , Mice , Microbial Sensitivity Tests , Microbial Viability/drug effects , Microscopy, Electron, Transmission , Models, Molecular , Mutation , Peptidomimetics/adverse effects , Photoaffinity LabelsABSTRACT
Shigella flexneri proliferate in infected human epithelial cells at exceptionally high rates. This vigorous growth has important consequences for rapid progression to life-threatening bloody diarrhea, but the underlying metabolic mechanisms remain poorly understood. Here, we used metabolomics, proteomics, and genetic experiments to determine host and Shigella metabolism during infection in a cell culture model. The data suggest that infected host cells maintain largely normal fluxes through glycolytic pathways, but the entire output of these pathways is captured by Shigella, most likely in the form of pyruvate. This striking strategy provides Shigella with an abundant favorable energy source, while preserving host cell ATP generation, energy charge maintenance, and survival, despite ongoing vigorous exploitation. Shigella uses a simple three-step pathway to metabolize pyruvate at high rates with acetate as an excreted waste product. The crucial role of this pathway for Shigella intracellular growth suggests targets for antimicrobial chemotherapy of this devastating disease.
