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Velkov T, Gallardo-Godoy A, Swarbrick JD, Blaskovich MAT, Elliott AG, Han M, Thompson PE, Roberts KD, Huang JX, Becker B, Butler MS, Lash LH, Henriques ST, Nation RL, Sivanesan S, Sani MA, Separovic F, Mertens H, Bulach D, Seemann T, Owen J, Li J, Cooper MA. Structure, Function, and Biosynthetic Origin of Octapeptin Antibiotics Active against Extensively Drug-Resistant Gram-Negative Bacteria. Cell Chem Biol 2018; 25:380-391.e5. [PMID: 29396290 DOI: 10.1016/j.chembiol.2018.01.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 09/03/2017] [Accepted: 12/29/2017] [Indexed: 01/06/2023]
Abstract
Resistance to the last-resort antibiotic colistin is now widespread and new therapeutics are urgently required. We report the first in toto chemical synthesis and pre-clinical evaluation of octapeptins, a class of lipopeptides structurally related to colistin. The octapeptin biosynthetic cluster consisted of three non-ribosomal peptide synthetases (OctA, OctB, and OctC) that produced an amphiphilic antibiotic, octapeptin C4, which was shown to bind to and depolarize membranes. While active against multi-drug resistant (MDR) strains in vitro, octapeptin C4 displayed poor in vivo efficacy, most likely due to high plasma protein binding. Nuclear magnetic resonance solution structures, empirical structure-activity and structure-toxicity models were used to design synthetic octapeptins active against MDR and extensively drug-resistant (XDR) bacteria. The scaffold was then subtly altered to reduce plasma protein binding, while maintaining activity against MDR and XDR bacteria. In vivo efficacy was demonstrated in a murine bacteremia model with a colistin-resistant P. aeruginosa clinical isolate.
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Affiliation(s)
- Tony Velkov
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
| | | | - James D Swarbrick
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052 VIC, Australia
| | - Mark A T Blaskovich
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Alysha G Elliott
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Meiling Han
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052 VIC, Australia
| | - Philip E Thompson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052 VIC, Australia
| | - Kade D Roberts
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052 VIC, Australia
| | - Johnny X Huang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bernd Becker
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Mark S Butler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Lawrence H Lash
- Department of Pharmacology, Wayne State University, School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201, USA
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052 VIC, Australia
| | - Sivashangarie Sivanesan
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052 VIC, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | | | - Dieter Bulach
- Department of Immunology and Microbiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Torsten Seemann
- Department of Immunology and Microbiology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jeremy Owen
- School of Biological Sciences, Victoria University, Wellington 6012, New Zealand
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052 VIC, Australia.
| | - Matthew A Cooper
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
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Abstract
Covering: 1975 up to the end of 2016The decline in the discovery and development of novel antibiotics has resulted in the emergence of bacteria that are resistant to almost all available antibiotics. Currently, polymyxin B and E (colistin) are being used as the last-line therapy against life-threatening infections, unfortunately resistance to polymyxins in both the community and hospital setting is becoming more common. Octapeptins are structurally related non-ribosomal lipopeptide antibiotics that do not exhibit cross-resistance with polymyxins and have a broader spectrum of activity that includes Gram-positive bacteria. This makes them a precious and finite resource for the development of new antibiotics against these problematic polymyxin-resistant Gram-negative pathogens, in particular Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. This review surveys the progress in understanding octapeptin chemistry, mechanisms of antibacterial activity and biosynthesis. With the lack of cross-resistance and their broad antibacterial activity, the octapeptins represent ideal candidates for the development of a new generation of polymyxin-like lipopeptide antibiotics targeting polymyxin-resistant 'superbugs'.
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Affiliation(s)
- Tony Velkov
- Drug Development and Innovation, Drug Delivery, Disposition and Dynamics, Australia.
| | - Kade D Roberts
- Drug Development and Innovation, Drug Delivery, Disposition and Dynamics, Australia. and Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, VIC, 3800, Australia.
| | - Jian Li
- Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, VIC, 3800, Australia.
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Battacin (Octapeptin B5), a new cyclic lipopeptide antibiotic from Paenibacillus tianmuensis active against multidrug-resistant Gram-negative bacteria. Antimicrob Agents Chemother 2011; 56:1458-65. [PMID: 22183171 DOI: 10.1128/aac.05580-11] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hospital-acquired infections caused by drug-resistant bacteria are a significant challenge to patient safety. Numerous clinical isolates resistant to almost all commercially available antibiotics have emerged. Thus, novel antimicrobial agents, specifically those for multidrug-resistant Gram-negative bacteria, are urgently needed. In the current study, we report the isolation, structure elucidation, and preliminary biological characterization of a new cationic lipopeptide antibiotic, battacin or octapeptin B5, produced from a Paenibacillus tianmuensis soil isolate. Battacin kills bacteria in vitro and has potent activity against Gram-negative bacteria, including multidrug-resistant and extremely drug-resistant clinical isolates. Hospital strains of Escherichia coli and Pseudomonas aeruginosa are the pathogens most sensitive to battacin, with MICs of 2 to 4 μg/ml. The ability of battacin to disrupt the outer membrane of Gram-negative bacteria is comparable to that of polymyxin B, the last-line therapy for infections caused by antibiotic-resistant Gram-negative bacteria. However, the capacity of battacin to permeate bacterial plasma membranes is less extensive than that of polymyxin B. The bactericidal kinetics of battacin correlate with the depolarization of the cell membrane, suggesting that battacin kills bacteria by disrupting the cytoplasmic membrane. Other studies indicate that battacin is less acutely toxic than polymyxin B and has potent in vivo biological activity against E. coli. Based on the findings of the current study, battacin may be considered a potential therapeutic agent for the treatment of infections caused by antibiotic-resistant Gram-negative bacteria.
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