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Wesseling CJ, Martin NI. Synergy by Perturbing the Gram-Negative Outer Membrane: Opening the Door for Gram-Positive Specific Antibiotics. ACS Infect Dis 2022; 8:1731-1757. [PMID: 35946799 PMCID: PMC9469101 DOI: 10.1021/acsinfecdis.2c00193] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
New approaches to target antibacterial agents toward Gram-negative bacteria are key, given the rise of antibiotic resistance. Since the discovery of polymyxin B nonapeptide as a potent Gram-negative outer membrane (OM)-permeabilizing synergist in the early 1980s, a vast amount of literature on such synergists has been published. This Review addresses a range of peptide-based and small organic compounds that disrupt the OM to elicit a synergistic effect with antibiotics that are otherwise inactive toward Gram-negative bacteria, with synergy defined as a fractional inhibitory concentration index (FICI) of <0.5. Another requirement for the inclusion of the synergists here covered is their potentiation of a specific set of clinically used antibiotics: erythromycin, rifampicin, novobiocin, or vancomycin. In addition, we have focused on those synergists with reported activity against Gram-negative members of the ESKAPE family of pathogens namely, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and/or Acinetobacter baumannii. In cases where the FICI values were not directly reported in the primary literature but could be calculated from the published data, we have done so, allowing for more direct comparison of potency with other synergists. We also address the hemolytic activity of the various OM-disrupting synergists reported in the literature, an effect that is often downplayed but is of key importance in assessing the selectivity of such compounds for Gram-negative bacteria.
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Mmatli M, Mbelle NM, Osei Sekyere J. Global epidemiology, genetic environment, risk factors and therapeutic prospects of mcr genes: A current and emerging update. Front Cell Infect Microbiol 2022; 12:941358. [PMID: 36093193 PMCID: PMC9462459 DOI: 10.3389/fcimb.2022.941358] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/01/2022] [Indexed: 12/28/2022] Open
Abstract
Background Mobile colistin resistance (mcr) genes modify Lipid A molecules of the lipopolysaccharide, changing the overall charge of the outer membrane. Results and discussion Ten mcr genes have been described to date within eleven Enterobacteriaceae species, with Escherichia coli, Klebsiella pneumoniae, and Salmonella species being the most predominant. They are present worldwide in 72 countries, with animal specimens currently having the highest incidence, due to the use of colistin in poultry for promoting growth and treating intestinal infections. The wide dissemination of mcr from food animals to meat, manure, the environment, and wastewater samples has increased the risk of transmission to humans via foodborne and vector-borne routes. The stability and spread of mcr genes were mediated by mobile genetic elements such as the IncHI2 conjugative plasmid, which is associated with multiple mcr genes and other antibiotic resistance genes. The cost of acquiring mcr is reduced by compensatory adaptation mechanisms. MCR proteins are well conserved structurally and via enzymatic action. Thus, therapeutics found effective against MCR-1 should be tested against the remaining MCR proteins. Conclusion The dissemination of mcr genes into the clinical setting, is threatening public health by limiting therapeutics options available. Combination therapies are a promising option for managing and treating colistin-resistant Enterobacteriaceae infections whilst reducing the toxic effects of colistin.
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Affiliation(s)
- Masego Mmatli
- Department of Medical Microbiology, School of Medicine, University of Pretoria, Pretoria, South Africa
| | - Nontombi Marylucy Mbelle
- Department of Medical Microbiology, School of Medicine, University of Pretoria, Pretoria, South Africa
| | - John Osei Sekyere
- Department of Medical Microbiology, School of Medicine, University of Pretoria, Pretoria, South Africa
- Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, IN, United States
- Department of Dermatology, School of Medicine, University of Pretoria, Pretoria, South Africa
- *Correspondence: John Osei Sekyere, ;
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New potentiators of ineffective antibiotics: Targeting the Gram-negative outer membrane to overcome intrinsic resistance. Curr Opin Chem Biol 2021; 66:102099. [PMID: 34808425 DOI: 10.1016/j.cbpa.2021.102099] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 09/30/2021] [Accepted: 10/07/2021] [Indexed: 12/20/2022]
Abstract
Because of the rise in antibiotic resistance and the dwindling pipeline of effective antibiotics, it is imperative to explore avenues that breathe new life into existing drugs. This is particularly important for intrinsically resistant Gram-negative bacteria, which are exceedingly difficult to treat. The Gram-negative outer membrane (OM) prevents the entry of a plethora of antibiotics that are effective against Gram-positive bacteria, despite the presence of the targets of these drugs. Uncovering molecules that increase the permeability of the OM to sensitize Gram-negative bacteria to otherwise ineffective antibiotics is an approach that has recently garnered increased attention in the field. In this review, we survey chemical matter which has been shown to potentiate antibiotics against Gram-negative bacteria by perturbing the OM. These include peptides, nanoparticles, macromolecules, antibiotic conjugates, and small molecules.
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Mood EH, Goltermann L, Brolin C, Cavaco LM, Nejad AJ, Yavari N, Frederiksen N, Franzyk H, Nielsen PE. Antibiotic Potentiation in Multidrug-Resistant Gram-Negative Pathogenic Bacteria by a Synthetic Peptidomimetic. ACS Infect Dis 2021; 7:2152-2163. [PMID: 34227804 DOI: 10.1021/acsinfecdis.1c00147] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The peptidomimetic H-[NLys-tBuAla]6-NH2 (CEP-136), which exhibits low inherent antimicrobial activity against Gram-negative bacteria (MIC = 16-64 μM), was shown to significantly potentiate the antibacterial activity of several clinically important antibiotics against the human pathogens Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. Thus, the antibacterial spectrum of rifampicin, clarithromycin, and azithromycin could be extended to include also these Gram-negative bacteria. Additionally, the potentiation effect was demonstrated in a panel of clinically relevant multidrug-resistant isolates including extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing as well as colistin-resistant strains. For some peptidomimetic-antibiotic combinations, the strong synergy corresponded to a more than 50-fold reduction of the minimal inhibitory concentration of the antibiotic. Mechanistic studies indicate that the potentiation arises from a permeabilization effect exerted on the outer membrane lipopolysaccharide layer of the Gram-negative bacteria without significant disruption of the inner membrane. Furthermore, the peptidomimetic enhancer exhibited only a marginal effect on the viability of mammalian HepG2 cells even at concentrations 100-fold higher than that enabling the antibiotic enhancement. Also, a low hemolytic activity combined with limited in vivo acute toxicity of CEP-136 in healthy mice allowed in vivo validation of the potentiation effect on both rifampicin and azithromycin treatment in a murine peritonitis model. Thus, CEP-136 is an interesting hit compound for further development of effective adjuvants for repurposing antibiotics for use against infections by multidrug-resistant Gram-negative bacteria.
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Affiliation(s)
- Elnaz Harifi Mood
- Center for Peptide-based Antibiotics, Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Lise Goltermann
- Center for Peptide-based Antibiotics, Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Camilla Brolin
- Center for Peptide-based Antibiotics, Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Lina M. Cavaco
- Department for Bacteria Parasites and Fungi, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen, Denmark
| | - Alireza Japoni Nejad
- Center for Peptide-based Antibiotics, Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Niloofar Yavari
- Center for Peptide-based Antibiotics, Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Nicki Frederiksen
- Center for Peptide-based Antibiotics, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100 Copenhagen, Denmark
| | - Henrik Franzyk
- Center for Peptide-based Antibiotics, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100 Copenhagen, Denmark
| | - Peter E. Nielsen
- Center for Peptide-based Antibiotics, Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
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McCarthy MW. Clinical Pharmacokinetics and Pharmacodynamics of Lefamulin. Clin Pharmacokinet 2021; 60:1387-1394. [PMID: 34254252 DOI: 10.1007/s40262-021-01056-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2021] [Indexed: 11/29/2022]
Abstract
Lefamulin (Xenleta) has been approved by the US FDA for the treatment of community-acquired bacterial pneumonia (CABP). It may be taken intravenously or orally and has activity against a broad range of pulmonary pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydophila pneumonia, as well as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Lefamulin has an adverse effect profile that is similar to other antimicrobial agents commonly used to treat CABP. Despite these promising features, the use of lefamulin remains limited in clinical practice. However, given the rise of antibiotic-resistant organisms, this may soon change. This review examines what is known about the pharmacokinetics and pharmacodynamics of lefamulin and looks ahead to its potential applications in clinical practice, including the treatment of sexually transmitted infections such as multidrug-resistant Mycoplasma genitalium, as well as its role as a synergistic agent used in combination with other antimicrobials in the treatment of drug-resistant organisms.
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Affiliation(s)
- Matthew William McCarthy
- Weill Cornell Medicine and NewYork-Presbyterian Hospital, 525 E. 68th Street, New York, NY, 10065, USA.
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Klobucar K, Côté JP, French S, Borrillo L, Guo ABY, Serrano-Wu MH, Lee KK, Hubbard B, Johnson JW, Gaulin JL, Magolan J, Hung DT, Brown ED. Chemical Screen for Vancomycin Antagonism Uncovers Probes of the Gram-Negative Outer Membrane. ACS Chem Biol 2021; 16:929-942. [PMID: 33974796 DOI: 10.1021/acschembio.1c00179] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The outer membrane of Gram-negative bacteria is a formidable permeability barrier which allows only a small subset of chemical matter to penetrate. This outer membrane barrier can hinder the study of cellular processes and compound mechanism of action, as many compounds including antibiotics are precluded from entry despite having intracellular targets. Consequently, outer membrane permeabilizing compounds are invaluable tools in such studies. Many existing compounds known to perturb the outer membrane also impact inner membrane integrity, such as polymyxins and their derivatives, making these probes nonspecific. We performed a screen of ∼140 000 diverse synthetic compounds, for those that antagonized the growth inhibitory activity of vancomycin at 15 °C in Escherichia coli, to enrich for chemicals capable of perturbing the outer membrane. This led to the discovery that liproxstatin-1, an inhibitor of ferroptosis in human cells, and MAC-0568743, a novel cationic amphiphile, could potentiate the activity of large-scaffold antibiotics with low permeation into Gram-negative bacteria at 37 °C. Liproxstatin-1 and MAC-0568743 were found to physically disrupt the integrity of the outer membrane through interactions with lipopolysaccharide in the outer leaflet of the outer membrane. We showed that these compounds selectively disrupt the outer membrane while minimally impacting inner membrane integrity, particularly at the concentrations needed to potentiate Gram-positive-targeting antibiotics. Further exploration of these molecules and their structural analogues is a promising avenue for the development of outer membrane specific probes.
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Affiliation(s)
- Kristina Klobucar
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Jean-Philippe Côté
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Shawn French
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Louis Borrillo
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Amelia Bing Ya Guo
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Michael H. Serrano-Wu
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Katie K. Lee
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Brian Hubbard
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Jarrod W. Johnson
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Jeffrey L. Gaulin
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Jakob Magolan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Deborah T. Hung
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
| | - Eric D. Brown
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
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Wesseling CMJ, Wood TM, Slingerland CJ, Bertheussen K, Lok S, Martin NI. Thrombin-Derived Peptides Potentiate the Activity of Gram-Positive-Specific Antibiotics against Gram-Negative Bacteria. Molecules 2021; 26:molecules26071954. [PMID: 33808488 PMCID: PMC8037310 DOI: 10.3390/molecules26071954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 12/13/2022] Open
Abstract
The continued rise of antibiotic resistance threatens to undermine the utility of the world’s current antibiotic arsenal. This problem is particularly troubling when it comes to Gram-negative pathogens for which there are inherently fewer antibiotics available. To address this challenge, recent attention has been focused on finding compounds capable of disrupting the Gram-negative outer membrane as a means of potentiating otherwise Gram-positive-specific antibiotics. In this regard, agents capable of binding to the lipopolysaccharide (LPS) present in the Gram-negative outer membrane are of particular interest as synergists. Recently, thrombin-derived C-terminal peptides (TCPs) were reported to exhibit unique LPS-binding properties. We here describe investigations establishing the capacity of TCPs to act as synergists with the antibiotics erythromycin, rifampicin, novobiocin, and vancomycin against multiple Gram-negative strains including polymyxin-resistant clinical isolates. We further assessed the structural features most important for the observed synergy and characterized the outer membrane permeabilizing activity of the most potent synergists. Our investigations highlight the potential for such peptides in expanding the therapeutic range of antibiotics typically only used to treat Gram-positive infections.
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Affiliation(s)
- Charlotte M. J. Wesseling
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 Leiden, The Netherlands; (C.M.J.W.); (T.M.W.); (C.J.S.); (K.B.); (S.L.)
| | - Thomas M. Wood
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 Leiden, The Netherlands; (C.M.J.W.); (T.M.W.); (C.J.S.); (K.B.); (S.L.)
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 Utrecht, The Netherlands
| | - Cornelis J. Slingerland
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 Leiden, The Netherlands; (C.M.J.W.); (T.M.W.); (C.J.S.); (K.B.); (S.L.)
| | - Kristine Bertheussen
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 Leiden, The Netherlands; (C.M.J.W.); (T.M.W.); (C.J.S.); (K.B.); (S.L.)
- Bio-Organic Synthesis Group, Leiden Institute of Chemistry, Leiden University, 2333 Leiden, The Netherlands
| | - Samantha Lok
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 Leiden, The Netherlands; (C.M.J.W.); (T.M.W.); (C.J.S.); (K.B.); (S.L.)
| | - Nathaniel I. Martin
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 Leiden, The Netherlands; (C.M.J.W.); (T.M.W.); (C.J.S.); (K.B.); (S.L.)
- Correspondence:
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Excretion of the Polymyxin Derivative NAB739 in Murine Urine. Antibiotics (Basel) 2020; 9:antibiotics9040143. [PMID: 32230751 PMCID: PMC7235871 DOI: 10.3390/antibiotics9040143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/19/2020] [Accepted: 03/25/2020] [Indexed: 11/18/2022] Open
Abstract
Extremely multiresistant strains of Enterobacteriaceae are emerging and spreading at a worrisome pace. Polymyxins are used as the last-resort therapy against such strains, in spite of their nephrotoxicity. We have previously shown that novel polymyxin derivatives NAB739 and NAB815 are less nephrotoxic in cynomolgus monkeys than polymyxin B and are therapeutic in murine Escherichia coli pyelonephritis at doses only one-tenth of that needed for polymyxin B. Here we evaluated whether the increased efficacy is due to increased excretion of NAB739 in urine. Mice were treated with NAB739 and polymyxin B four times subcutaneously at doses of 0.25, 0.5, 1, 2, and 4 mg/kg. In plasma, a clear dose–response relationship was observed. The linearity of Cmax with the dose was 0.9987 for NAB739 and 0.975 for polymyxin B. After administration of NAB739 at a dose of 0.25 mg/kg, its plasma concentrations at all tested time points were above 0.5 µg/mL while after administration at a dose of 0.5 mg/kg its plasma concentrations exceeded 1 µg/mL. The Cmax of NAB739 in plasma was up to 1.5-times higher after single (first) administration and up to two-times higher after the last administration when compared to polymyxin B. Polymyxin B was not detected in urine samples even when administered at 4 mg/kg. In contrast, the concentration of NAB739 in urine after single administration at a dose of 0.25 mg/kg was above 1 µg/mL and after administration of 0.5 mg/kg its average urine concentration exceeded 2 µg/mL. At the NAB739 dose of 4 mg/kg, the urinary concentrations were higher than 35 µg/mL. These differences explain our previous finding that NAB739 is much more efficacious than polymyxin B in the therapy of murine E. coli pyelonephritis.
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Paenipeptin Analogues Potentiate Clarithromycin and Rifampin against mcr-1-Mediated Polymyxin-Resistant Escherichia coli In Vivo. Antimicrob Agents Chemother 2020; 64:AAC.02045-19. [PMID: 32015033 DOI: 10.1128/aac.02045-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/24/2020] [Indexed: 12/20/2022] Open
Abstract
Polymyxin resistance mediated by the mcr-1 gene threatens the last-resort antibiotics. Linear lipopeptide paenipeptin analogues 1 and 15 disrupted the outer membrane of Gram-negative pathogens and potentiated clarithromycin and rifampin against mcr-1-positive Escherichia coli from the FDA-CDC Antimicrobial Resistance Isolate Bank. In the presence of paenipeptin, clarithromycin and rifampin resulted in over 3-log reduction of E. coli in vitro Moreover, paenipeptin-antibiotic combinations significantly reduced E. coli in a murine thigh infection model.
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Vaara M. Polymyxins and Their Potential Next Generation as Therapeutic Antibiotics. Front Microbiol 2019; 10:1689. [PMID: 31404242 PMCID: PMC6671869 DOI: 10.3389/fmicb.2019.01689] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/09/2019] [Indexed: 01/10/2023] Open
Abstract
The discovery of polymyxins, highly basic lipodecapeptides, was published independently by three laboratories in 1947. Their clinical use, however, was abandoned in the sixties because of nephrotoxicity and because better-tolerated drugs belonging to other antibiotic classes were discovered. Now polymyxins have resurged as the last-resort drugs against extremely multi-resistant strains, even though their nephrotoxicity forces clinicians to administer them at doses that are lower than those required for optimal efficacy. As their therapeutic windows are very narrow, the use of polymyxins has received lots of justified criticism. To address this criticism, consensus guidelines for the optimal use of polymyxins have just been published. Quite obviously, too, improved polymyxins with increased efficacy and lowered nephrotoxicity would be more than welcome. Over the last few years, more than USD 40 million of public money has been used in programs that aim at the design of novel polymyxin derivatives. This perspective article points out that polymyxins do have potential for further development and that the novel derivatives already now at hand might offer major advantages over the old polymyxins.
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Affiliation(s)
- Martti Vaara
- Northern Antibiotics Ltd., Espoo, Finland
- Department of Bacteriology and Immunology, Helsinki University Medical School, Helsinki, Finland
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Polymyxin Derivatives that Sensitize Gram-Negative Bacteria to Other Antibiotics. Molecules 2019; 24:molecules24020249. [PMID: 30641878 PMCID: PMC6359160 DOI: 10.3390/molecules24020249] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 12/27/2018] [Accepted: 01/07/2019] [Indexed: 01/11/2023] Open
Abstract
Polymyxins (polymyxin B (PMB) and polymyxin E (colistin)) are cyclic lipodecapeptide antibiotics, highly basic due to five free amino groups, and rapidly bactericidal against Gram-negative bacteria, such as the majority of Enterobacteriaceae as well as Acinetobacter baumannii and Pseudomonas aeruginosa. Their clinical use was abandoned in the 1960s because of nephrotoxicity and because better-tolerated drugs belonging to other antibiotic classes were introduced. Now, due to the global dissemination of extremely-drug resistant Gram-negative bacterial strains, polymyxins have resurged as the last-line drugs against those strains. Novel derivatives that are less toxic and/or more effective at tolerable doses are currently under preclinical development and their properties have recently been described in several extensive reviews. Other derivatives lack any direct bactericidal activity but damage the outermost permeability barrier, the outer membrane, of the target bacteria and make it more permeable to many other antibiotics. This review describes the properties of three thus far best-characterized “permeabilizer” derivatives, i.e., the classic permeabilizer polymyxin B nonapeptide (PMBN), NAB7061, and SPR741/NAB741, a compound that recently successfully passed the clinical phase 1. Also, a few other permeabilizer compounds are brought up.
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