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Greenwald MA, Meinig SL, Plott LM, Roca C, Higgs MG, Vitko NP, Markovetz MR, Rouillard KR, Carpenter J, Kesimer M, Hill DB, Schisler JC, Wolfgang MC. Mucus polymer concentration and in vivo adaptation converge to define the antibiotic response of Pseudomonas aeruginosa during chronic lung infection. mBio 2024; 15:e0345123. [PMID: 38651896 DOI: 10.1128/mbio.03451-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024] Open
Abstract
The airway milieu of individuals with muco-obstructive airway diseases (MADs) is defined by the accumulation of dehydrated mucus due to hyperabsorption of airway surface liquid and defective mucociliary clearance. Pathological mucus becomes progressively more viscous with age and disease severity due to the concentration and overproduction of mucin and accumulation of host-derived extracellular DNA (eDNA). Respiratory mucus of MADs provides a niche for recurrent and persistent colonization by respiratory pathogens, including Pseudomonas aeruginosa, which is responsible for the majority of morbidity and mortality in MADs. Despite high concentration inhaled antibiotic therapies and the absence of antibiotic resistance, antipseudomonal treatment failure in MADs remains a significant clinical challenge. Understanding the drivers of antibiotic tolerance is essential for developing more effective treatments that eradicate persistent infections. The complex and dynamic environment of diseased airways makes it difficult to model antibiotic efficacy in vitro. We aimed to understand how mucin and eDNA concentrations, the two dominant polymers in respiratory mucus, alter the antibiotic tolerance of P. aeruginosa. Our results demonstrate that polymer concentration and molecular weight affect P. aeruginosa survival post antibiotic challenge. Polymer-driven antibiotic tolerance was not explicitly associated with reduced antibiotic diffusion. Lastly, we established a robust and standardized in vitro model for recapitulating the ex vivo antibiotic tolerance of P. aeruginosa observed in expectorated sputum across age, underlying MAD etiology, and disease severity, which revealed the inherent variability in intrinsic antibiotic tolerance of host-evolved P. aeruginosa populations. IMPORTANCE Antibiotic treatment failure in Pseudomonas aeruginosa chronic lung infections is associated with increased morbidity and mortality, illustrating the clinical challenge of bacterial infection control. Understanding the underlying infection environment, as well as the host and bacterial factors driving antibiotic tolerance and the ability to accurately recapitulate these factors in vitro, is crucial for improving antibiotic treatment outcomes. Here, we demonstrate that increasing concentration and molecular weight of mucin and host eDNA drive increased antibiotic tolerance to tobramycin. Through systematic testing and modeling, we identified a biologically relevant in vitro condition that recapitulates antibiotic tolerance observed in ex vivo treated sputum. Ultimately, this study revealed a dominant effect of in vivo evolved bacterial populations in defining inter-subject ex vivo antibiotic tolerance and establishes a robust and translatable in vitro model for therapeutic development.
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Affiliation(s)
- Matthew A Greenwald
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Suzanne L Meinig
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Lucas M Plott
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Cristian Roca
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew G Higgs
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Nicholas P Vitko
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew R Markovetz
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Kaitlyn R Rouillard
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jerome Carpenter
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Mehmet Kesimer
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - David B Hill
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jonathan C Schisler
- Department of Pharmacology, The University of North Carolina, Chapel Hill, North Carolina, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew C Wolfgang
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
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Rouillard KR, Esther CP, Kissner WJ, Plott LM, Bowman DW, Markovetz MR, Hill DB. Combination treatment to improve mucociliary transport of Pseudomonas aeruginosa biofilms. PLoS One 2024; 19:e0294120. [PMID: 38394229 PMCID: PMC10890754 DOI: 10.1371/journal.pone.0294120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 10/25/2023] [Indexed: 02/25/2024] Open
Abstract
People with muco-obstructive pulmonary diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) often have acute or chronic respiratory infections that are difficult to treat due in part to the accumulation of hyperconcentrated mucus within the airway. Mucus accumulation and obstruction promote chronic inflammation and infection and reduce therapeutic efficacy. Bacterial aggregates in the form of biofilms exhibit increased resistance to mechanical stressors from the immune response (e.g., phagocytosis) and chemical treatments including antibiotics. Herein, combination treatments designed to disrupt the mechanical properties of biofilms and potentiate antibiotic efficacy are investigated against mucus-grown Pseudomonas aeruginosa biofilms and optimized to 1) alter biofilm viscoelastic properties, 2) increase mucociliary transport rates, and 3) reduce bacterial viability. A disulfide bond reducing agent (tris(2-carboxyethyl)phosphine, TCEP), a surfactant (NP40), a biopolymer (hyaluronic acid, HA), a DNA degradation enzyme (DNase), and an antibiotic (tobramycin) are tested in various combinations to maximize biofilm disruption. The viscoelastic properties of biofilms are quantified with particle tracking microrheology and transport rates are quantified in a mucociliary transport device comprised of fully differentiated primary human bronchial epithelial cells. The combination of the NP40 with hyaluronic acid and tobramycin was the most effective at increasing mucociliary transport rates, decreasing the viscoelastic properties of mucus, and reducing bacterial viability. Multimechanistic targeting of biofilm infections may ultimately result in improved clinical outcomes, and the results of this study may be translated into future in vivo infection models.
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Affiliation(s)
- Kaitlyn R. Rouillard
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | | | - William J. Kissner
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - Lucas M. Plott
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - Dean W. Bowman
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - Matthew R. Markovetz
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
| | - David B. Hill
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC, United States of America
- Joint Department of Biomedical Engineering, UNC Chapel Hill, Chapel Hill, NC, United States of America
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Greenwald MA, Meinig SL, Plott LM, Roca C, Higgs MG, Vitko NP, Markovetz MR, Rouillard KR, Carpenter J, Kesimer M, Hill DB, Schisler JC, Wolfgang MC. Mucus polymer concentration and in vivo adaptation converge to define the antibiotic response of Pseudomonas aeruginosa during chronic lung infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572620. [PMID: 38187602 PMCID: PMC10769284 DOI: 10.1101/2023.12.20.572620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The airway milieu of individuals with muco-obstructive airway diseases (MADs) is defined by the accumulation of dehydrated mucus due to hyperabsorption of airway surface liquid and defective mucociliary clearance. Pathological mucus becomes progressively more viscous with age and disease severity due to the concentration and overproduction of mucin and accumulation of host-derived extracellular DNA (eDNA). Respiratory mucus of MADs provides a niche for recurrent and persistent colonization by respiratory pathogens, including Pseudomonas aeruginosa , which is responsible for the majority of morbidity and mortality in MADs. Despite high concentration inhaled antibiotic therapies and the absence of antibiotic resistance, antipseudomonal treatment failure in MADs remains a significant clinical challenge. Understanding the drivers of antibiotic recalcitrance is essential for developing more effective treatments that eradicate persistent infections. The complex and dynamic environment of diseased airways makes it difficult to model antibiotic efficacy in vitro . We aimed to understand how mucin and eDNA concentrations, the two dominant polymers in respiratory mucus, alter the antibiotic tolerance of P. aeruginosa . Our results demonstrate that polymer concentration and molecular weight affect P. aeruginosa survival post antibiotic challenge. Polymer-driven antibiotic tolerance was not explicitly associated with reduced antibiotic diffusion. Lastly, we established a robust and standardized in vitro model for recapitulating the ex vivo antibiotic tolerance of P. aeruginosa observed in expectorated sputum across age, underlying MAD etiology, and disease severity, which revealed the inherent variability in intrinsic antibiotic tolerance of host-evolved P. aeruginosa populations. Importance Antibiotic treatment failure in Pseudomonas aeruginosa chronic lung infections is associated with increased morbidity and mortality, illustrating the clinical challenge of bacterial infection control. Understanding the underlying infection environment, as well as the host and bacterial factors driving antibiotic tolerance and the ability to accurately recapitulate these factors in vitro , is crucial for improving antibiotic treatment outcomes. Here, we demonstrate that increasing concentration and molecular weight of mucin and host eDNA drive increased antibiotic tolerance to tobramycin. Through systematic testing and modeling, we identified a biologically relevant in vitro condition that recapitulates antibiotic tolerance observed in ex vivo treated sputum. Ultimately, this study revealed a dominant effect of in vivo evolved bacterial populations in defining inter-subject ex vivo antibiotic tolerance and establishes a robust and translatable in vitro model for therapeutic development.
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Cholon DM, Greenwald MA, Higgs MG, Quinney NL, Boyles SE, Meinig SL, Minges JT, Chaubal A, Tarran R, Ribeiro CMP, Wolfgang MC, Gentzsch M. A Novel Co-Culture Model Reveals Enhanced CFTR Rescue in Primary Cystic Fibrosis Airway Epithelial Cultures with Persistent Pseudomonas aeruginosa Infection. Cells 2023; 12:2618. [PMID: 37998353 PMCID: PMC10670530 DOI: 10.3390/cells12222618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/31/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023] Open
Abstract
People with cystic fibrosis (pwCF) suffer from chronic and recurring bacterial lung infections that begin very early in life and contribute to progressive lung failure. CF is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which encodes an ion channel important for maintaining the proper hydration of pulmonary surfaces. When CFTR function is ablated or impaired, airways develop thickened, adherent mucus that contributes to a vicious cycle of infection and inflammation. Therapeutics for pwCF, called CFTR modulators, target the CFTR defect directly, restoring airway surface hydration and mucociliary clearance. However, even with CFTR modulator therapy, bacterial infections persist. To develop a relevant model of diseased airway epithelium, we established a primary human airway epithelium culture system with persistent Pseudomonas aeruginosa infection. We used this model to examine the effects of CFTR modulators on CFTR maturation, CFTR function, and bacterial persistence. We found that the presence of P. aeruginosa increased CFTR mRNA, protein, and function. We also found that CFTR modulators caused a decrease in P. aeruginosa burden. These results demonstrate the importance of including live bacteria to accurately model the CF lung, and that understanding the effects of infection on CFTR rescue by CFTR modulators is critical to evaluating and optimizing drug therapies for all pwCF.
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Affiliation(s)
- Deborah M. Cholon
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Matthew A. Greenwald
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Matthew G. Higgs
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nancy L. Quinney
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Susan E. Boyles
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Suzanne L. Meinig
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Pharmaceutical Product Development (PPD), Thermo Fisher Scientific, Morrisville, NC 27560, USA
| | - John T. Minges
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Ashlesha Chaubal
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Robert Tarran
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Division of Genetic, Department of Internal Medicine, Environmental and Inhalational Disease, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Carla M. P. Ribeiro
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Division of Pulmonary Diseases, Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Matthew C. Wolfgang
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Martina Gentzsch
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
- Division of Pediatric Pulmonology, Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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Agyeman AA, López-Causapé C, Rogers KE, Lucas DD, Cortés-Lara S, Gomis-Font MA, Fraile-Ribot P, Figuerola J, Lang Y, Franklyn ERT, Lee WL, Zhou J, Zhang Y, Bulitta JB, Boyce JD, Nation RL, Oliver A, Landersdorfer CB. Ceftolozane/tazobactam plus tobramycin against free-floating and biofilm bacteria of hypermutable Pseudomonas aeruginosa epidemic strains: Resistance mechanisms and synergistic activity. Int J Antimicrob Agents 2023; 62:106887. [PMID: 37315906 DOI: 10.1016/j.ijantimicag.2023.106887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/26/2023] [Accepted: 06/07/2023] [Indexed: 06/16/2023]
Abstract
OBJECTIVE Acute exacerbations of biofilm-associated Pseudomonas aeruginosa infections in cystic fibrosis (CF) have limited treatment options. Ceftolozane/tazobactam (alone and with a second antibiotic) has not yet been investigated against hypermutable clinical P. aeruginosa isolates in biofilm growth. This study aimed to evaluate, using an in vitro dynamic biofilm model, ceftolozane/tazobactam alone and in combination with tobramycin at simulated representative lung fluid pharmacokinetics against free-floating (planktonic) and biofilm states of two hypermutable P. aeruginosa epidemic strains (LES-1 and CC274) from adolescents with CF. METHODS Regimens were intravenous ceftolozane/tazobactam 4.5 g/day continuous infusion, inhaled tobramycin 300 mg 12-hourly, intravenous tobramycin 10 mg/kg 24-hourly, and both ceftolozane/tazobactam-tobramycin combinations. The isolates were susceptible to both antibiotics. Total and less-susceptible free-floating and biofilm bacteria were quantified over 120-168 h. Ceftolozane/tazobactam resistance mechanisms were investigated by whole-genome sequencing. Mechanism-based modelling of bacterial viable counts was performed. RESULTS Monotherapies of ceftolozane/tazobactam and tobramycin did not sufficiently suppress emergence of less-susceptible subpopulations, although inhaled tobramycin was more effective than intravenous tobramycin. Ceftolozane/tazobactam resistance development was associated with classical (AmpC overexpression plus structural modification) and novel (CpxR mutations) mechanisms depending on the strain. Against both isolates, combination regimens demonstrated synergy and completely suppressed the emergence of ceftolozane/tazobactam and tobramycin less-susceptible free-floating and biofilm bacterial subpopulations. CONCLUSION Mechanism-based modelling incorporating subpopulation and mechanistic synergy well described the antibacterial effects of all regimens against free-floating and biofilm bacterial states. These findings support further investigation of ceftolozane/tazobactam in combination with tobramycin against biofilm-associated P. aeruginosa infections in adolescents with CF.
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Affiliation(s)
- Akosua A Agyeman
- Centre for Medicine Use and Safety, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Carla López-Causapé
- Servicio de Microbiología, Hospital Universitario Son Espases-IdISBa, Palma de Mallorca, Spain; CIBER Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Kate E Rogers
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Deanna Deveson Lucas
- Monash Bioinformatics Platform, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Sara Cortés-Lara
- Servicio de Microbiología, Hospital Universitario Son Espases-IdISBa, Palma de Mallorca, Spain; CIBER Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Maria A Gomis-Font
- Servicio de Microbiología, Hospital Universitario Son Espases-IdISBa, Palma de Mallorca, Spain; CIBER Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Pablo Fraile-Ribot
- Servicio de Microbiología, Hospital Universitario Son Espases-IdISBa, Palma de Mallorca, Spain; CIBER Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Joan Figuerola
- Servicio de Pediatría, Hospital Universitario Son Espases-IdISBa, Palma de Mallorca, Spain
| | - Yinzhi Lang
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Eva R T Franklyn
- Centre for Medicine Use and Safety, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Wee Leng Lee
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Jieqiang Zhou
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Yongzhen Zhang
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Jurgen B Bulitta
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - John D Boyce
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Universitario Son Espases-IdISBa, Palma de Mallorca, Spain; CIBER Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain.
| | - Cornelia B Landersdorfer
- Centre for Medicine Use and Safety, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
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6
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Rouillard KR, Esther CP, Kissner WJ, Plott LM, Bowman DW, Markovetz MR, Hill DB. Combination Treatment to Improve Mucociliary Transport of Pseudomonas aeruginosa Biofilms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553173. [PMID: 37645913 PMCID: PMC10461968 DOI: 10.1101/2023.08.14.553173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
People with muco-obstructive pulmonary diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) often have acute or chronic respiratory infections that are difficult to treat due in part to the accumulation of hyperconcentrated mucus within the airway. Mucus accumulation and obstruction promote chronic inflammation and infection and reduce therapeutic efficacy. Bacterial aggregates in the form of biofilms exhibit increased resistance to mechanical stressors from the immune response (e.g., phagocytosis) and chemical treatments including antibiotics. Herein, combination treatments designed to disrupt the mechanical properties of biofilms and potentiate antibiotic efficacy are investigated against mucus-grown Pseudomonas aeruginosa biofilms and optimized to 1) alter biofilm viscoelastic properties, 2) increase mucociliary transport rates, and 3) reduce bacterial viability. A disulfide bond reducing agent (tris(2-carboxyethyl)phosphine, TCEP), a surfactant (NP40), a biopolymer (hyaluronic acid, HA), a DNA degradation enzyme (DNase), and an antibiotic (tobramycin) are tested in various combinations to maximize biofilm disruption. The viscoelastic properties of biofilms are quantified with particle tracking microrheology and transport rates are quantified in a mucociliary transport device comprised of fully differentiated primary human bronchial epithelial cells. The combination of the NP40 with hyaluronic acid and tobramycin was the most effective at increasing mucociliary transport rates, decreasing the viscoelastic properties of mucus, and reducing bacterial viability. Multimechanistic targeting of biofilm infections may ultimately result in improved clinical outcomes, and the results of this study may be translated into future in vivo infection models.
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Affiliation(s)
| | | | | | - Lucas M Plott
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC 27599
| | - Dean W Bowman
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC 27599
| | | | - David B Hill
- Marsico Lung Institute, UNC Chapel Hill, Chapel Hill, NC 27599
- Joint Department of Biomedical Engineering, UNC Chapel Hill, NC 27599
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Langton Hewer SC, Smith S, Rowbotham NJ, Yule A, Smyth AR. Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis. Cochrane Database Syst Rev 2023; 6:CD004197. [PMID: 37268599 PMCID: PMC10237531 DOI: 10.1002/14651858.cd004197.pub6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
BACKGROUND Respiratory tract infections with Pseudomonas aeruginosa occur in most people with cystic fibrosis (CF). Established chronic P aeruginosa infection is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate. This is an updated review. OBJECTIVES Does giving antibiotics for P aeruginosa infection in people with CF at the time of new isolation improve clinical outcomes (e.g. mortality, quality of life and morbidity), eradicate P aeruginosa infection, and delay the onset of chronic infection, but without adverse effects, compared to usual treatment or an alternative antibiotic regimen? We also assessed cost-effectiveness. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and conference proceedings. Latest search: 24 March 2022. We searched ongoing trials registries. Latest search: 6 April 2022. SELECTION CRITERIA We included randomised controlled trials (RCTs) of people with CF, in whom P aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous (IV) antibiotics with placebo, usual treatment or other antibiotic combinations. We excluded non-randomised trials and cross-over trials. DATA COLLECTION AND ANALYSIS Two authors independently selected trials, assessed risk of bias and extracted data. We assessed the certainty of the evidence using GRADE. MAIN RESULTS We included 11 trials (1449 participants) lasting between 28 days and 27 months; some had few participants and most had relatively short follow-up periods. Antibiotics in this review are: oral - ciprofloxacin and azithromycin; inhaled - tobramycin nebuliser solution for inhalation (TNS), aztreonam lysine (AZLI) and colistin; IV - ceftazidime and tobramycin. There was generally a low risk of bias from missing data. In most trials it was difficult to blind participants and clinicians to treatment. Two trials were supported by the manufacturers of the antibiotic used. TNS versus placebo TNS may improve eradication; fewer participants were still positive for P aeruginosa at one month (odds ratio (OR) 0.06, 95% confidence interval (CI) 0.02 to 0.18; 3 trials, 89 participants; low-certainty evidence) and two months (OR 0.15, 95% CI 0.03 to 0.65; 2 trials, 38 participants). We are uncertain whether the odds of a positive culture decrease at 12 months (OR 0.02, 95% CI 0.00 to 0.67; 1 trial, 12 participants). TNS (28 days) versus TNS (56 days) One trial (88 participants) comparing 28 days to 56 days TNS treatment found duration of treatment may make little or no difference in time to next isolation (hazard ratio (HR) 0.81, 95% CI 0.37 to 1.76; low-certainty evidence). Cycled TNS versus culture-based TNS One trial (304 children, one to 12 years old) compared cycled TNS to culture-based therapy and also ciprofloxacin to placebo. We found moderate-certainty evidence of an effect favouring cycled TNS therapy (OR 0.51, 95% CI 0.31 to 0.82), although the trial publication reported age-adjusted OR and no difference between groups. Ciprofloxacin versus placebo added to cycled and culture-based TNS therapy One trial (296 participants) examined the effect of adding ciprofloxacin versus placebo to cycled and culture-based TNS therapy. There is probably no difference between ciprofloxacin and placebo in eradicating P aeruginosa (OR 0.89, 95% CI 0.55 to 1.44; moderate-certainty evidence). Ciprofloxacin and colistin versus TNS We are uncertain whether there is any difference between groups in eradication of P aeruginosa at up to six months (OR 0.43, 95% CI 0.15 to 1.23; 1 trial, 58 participants) or up to 24 months (OR 0.76, 95% CI 0.24 to 2.42; 1 trial, 47 participants); there was a low rate of short-term eradication in both groups. Ciprofloxacin plus colistin versus ciprofloxacin plus TNS One trial (223 participants) found there may be no difference in positive respiratory cultures at 16 months between ciprofloxacin with colistin versus TNS with ciprofloxacin (OR 1.28, 95% CI 0.72 to 2.29; low-certainty evidence). TNS plus azithromycin compared to TNS plus oral placebo Adding azithromycin may make no difference to the number of participants eradicating P aeruginosa after a three-month treatment phase (risk ratio (RR) 1.01, 95% CI 0.75 to 1.35; 1 trial, 91 participants; low-certainty evidence); there was also no evidence of any difference in the time to recurrence. Ciprofloxacin and colistin versus no treatment A single trial only reported one of our planned outcomes; there were no adverse effects in either group. AZLI for 14 days plus placebo for 14 days compared to AZLI for 28 days We are uncertain whether giving 14 or 28 days of AZLI makes any difference to the proportion of participants having a negative respiratory culture at 28 days (mean difference (MD) -7.50, 95% CI -24.80 to 9.80; 1 trial, 139 participants; very low-certainty evidence). Ceftazidime with IV tobramycin compared with ciprofloxacin (both regimens in conjunction with three months colistin) IV ceftazidime with tobramycin compared with ciprofloxacin may make little or no difference to eradication of P aeruginosa at three months, sustained to 15 months, provided that inhaled antibiotics are also used (RR 0.84, 95 % CI 0.65 to 1.09; P = 0.18; 1 trial, 255 participants; high-certainty evidence). The results do not support using IV antibiotics over oral therapy to eradicate P aeruginosa, based on both eradication rate and financial cost. AUTHORS' CONCLUSIONS We found that nebulised antibiotics, alone or with oral antibiotics, were better than no treatment for early infection with P aeruginosa. Eradication may be sustained in the short term. There is insufficient evidence to determine whether these antibiotic strategies decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment. Four trials comparing two active treatments have failed to show differences in rates of eradication of P aeruginosa. One large trial showed that intravenous ceftazidime with tobramycin is not superior to oral ciprofloxacin when inhaled antibiotics are also used. There is still insufficient evidence to state which antibiotic strategy should be used for the eradication of early P aeruginosa infection in CF, but there is now evidence that intravenous therapy is not superior to oral antibiotics.
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Affiliation(s)
- Simon C Langton Hewer
- Paediatric Respiratory Medicine, Bristol Royal Hospital for Children, Bristol, UK
- Population Health Sciences, University of Bristol, Bristol, UK
| | - Sherie Smith
- Academic Unit of Lifespan and Population Health, School of Medicine, University of Nottingham, Nottingham, UK
| | - Nicola J Rowbotham
- Academic Unit of Lifespan and Population Health, School of Medicine, University of Nottingham, Nottingham, UK
| | - Alexander Yule
- Academic Unit of Lifespan and Population Health, School of Medicine, University of Nottingham, Nottingham, UK
| | - Alan R Smyth
- Academic Unit of Lifespan and Population Health, School of Medicine, University of Nottingham, Nottingham, UK
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Jean-Pierre F, Hampton TH, Schultz D, Hogan DA, Groleau MC, Déziel E, O'Toole GA. Community composition shapes microbial-specific phenotypes in a cystic fibrosis polymicrobial model system. eLife 2023; 12:81604. [PMID: 36661299 PMCID: PMC9897730 DOI: 10.7554/elife.81604] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 01/19/2023] [Indexed: 01/21/2023] Open
Abstract
Interspecies interactions can drive the emergence of unexpected microbial phenotypes that are not observed when studying monocultures. The cystic fibrosis (CF) lung consists of a complex environment where microbes, living as polymicrobial biofilm-like communities, are associated with negative clinical outcomes for persons with CF (pwCF). However, the current lack of in vitro models integrating the microbial diversity observed in the CF airway hampers our understanding of why polymicrobial communities are recalcitrant to therapy in this disease. Here, integrating computational approaches informed by clinical data, we built a mixed community of clinical relevance to the CF lung composed of Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus sanguinis, and Prevotella melaninogenica. We developed and validated this model biofilm community with multiple isolates of these four genera. When challenged with tobramycin, a front-line antimicrobial used to treat pwCF, the microorganisms in the polymicrobial community show altered sensitivity to this antibiotic compared to monospecies biofilms. We observed that wild-type P. aeruginosa is sensitized to tobramycin in a mixed community versus monoculture, and this observation holds across a range of community relative abundances. We also report that LasR loss-of-function, a variant frequently detected in the CF airway, drives tolerance of P. aeruginosa to tobramycin specifically in the mixed community. Our data suggest that the molecular basis of this community-specific recalcitrance to tobramycin for the P. aeruginosa lasR mutant is increased production of phenazines. Our work supports the importance of studying a clinically relevant model of polymicrobial biofilms to understand community-specific traits relevant to infections.
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Affiliation(s)
- Fabrice Jean-Pierre
- Department of Microbiology and Immunology, Geisel School of Medicine at DartmouthHanoverUnited States
| | - Thomas H Hampton
- Department of Microbiology and Immunology, Geisel School of Medicine at DartmouthHanoverUnited States
| | - Daniel Schultz
- Department of Microbiology and Immunology, Geisel School of Medicine at DartmouthHanoverUnited States
| | - Deborah A Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at DartmouthHanoverUnited States
| | - Marie-Christine Groleau
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche ScientifiqueLavalCanada
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche ScientifiqueLavalCanada
| | - George A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at DartmouthHanoverUnited States
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Smith S, Rowbotham NJ. Inhaled anti-pseudomonal antibiotics for long-term therapy in cystic fibrosis. Cochrane Database Syst Rev 2022; 11:CD001021. [PMID: 36373968 PMCID: PMC9662285 DOI: 10.1002/14651858.cd001021.pub4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inhaled antibiotics are commonly used to treat persistent airway infection with Pseudomonas aeruginosa that contributes to lung damage in people with cystic fibrosis. Current guidelines recommend inhaled tobramycin for individuals with cystic fibrosis and persistent Pseudomonas aeruginosa infection who are aged six years or older. The aim is to reduce bacterial load in the lungs so as to reduce inflammation and deterioration of lung function. This is an update of a previously published review. OBJECTIVES To evaluate the effects of long-term inhaled antibiotic therapy in people with cystic fibrosis on clinical outcomes (lung function, frequency of exacerbations and nutrition), quality of life and adverse events (including drug-sensitivity reactions and survival). SEARCH METHODS We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched ongoing trials registries. Date of last search: 28 June 2022. SELECTION CRITERIA We selected trials where people with cystic fibrosis received inhaled anti-pseudomonal antibiotic treatment for at least three months, treatment allocation was randomised or quasi-randomised, and there was a control group (either placebo, no placebo or another inhaled antibiotic). DATA COLLECTION AND ANALYSIS Two authors independently selected trials, judged the risk of bias, extracted data from these trials and judged the certainty of the evidence using the GRADE system. MAIN RESULTS The searches identified 410 citations to 125 trials; 18 trials (3042 participants aged between five and 45 years) met the inclusion criteria. Limited data were available for meta-analyses due to the variability of trial design and reporting of results. A total of 11 trials (1130 participants) compared an inhaled antibiotic to placebo or usual treatment for a duration between three and 33 months. Five trials (1255 participants) compared different antibiotics, two trials (585 participants) compared different regimens of tobramycin and one trial (90 participants) compared intermittent tobramycin with continuous tobramycin alternating with aztreonam. One trial (18 participants) compared an antibiotic to placebo and also to a different antibiotic and so fell into both groups. The most commonly studied antibiotic was tobramycin which was studied in 12 trials. Inhaled antibiotics compared to placebo We found that inhaled antibiotics may improve lung function measured in a variety of ways (4 trials, 814 participants). Compared to placebo, inhaled antibiotics may also reduce the frequency of exacerbations (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.47 to 0.93; 3 trials, 946 participants; low-certainty evidence). Inhaled antibiotics may lead to fewer days off school or work (quality of life measure) (mean difference (MD) -5.30 days, 95% CI -8.59 to -2.01; 1 trial, 245 participants; low-certainty evidence). There were insufficient data for us to be able to report an effect on nutritional outcomes and there was no effect on survival. There was no effect on antibiotic resistance seen in the two trials that were included in meta-analyses. We are uncertain of the effect of the intervention on adverse events (very low-certainty evidence), but tinnitus and voice alteration were the only events occurring more often in the inhaled antibiotics group. The overall certainty of evidence was deemed to be low for most outcomes due to risk of bias within the trials and imprecision due to low event rates. Different antibiotics or regimens compared Of the eight trials comparing different inhaled antibiotics or different antibiotic regimens, there was only one trial for each unique comparison. We found no differences between groups for any outcomes except for the following. Aztreonam lysine for inhalation probably improved forced expiratory volume at one second (FEV1) % predicted compared to tobramycin (MD -3.40%, 95% CI -6.63 to -0.17; 1 trial, 273 participants; moderate-certainty evidence). However, the method of defining the endpoint was different to the remaining trials and the participants were exposed to tobramycin for a long period making interpretation of the results problematic. We found no differences in any measure of lung function in the remaining comparisons. Trials measured pulmonary exacerbations in different ways and showed no differences between groups except for aztreonam lysine probably leading to fewer people needing treatment with additional antibiotics than with tobramycin (RR 0.66, 95% CI 0.51 to 0.86; 1 trial, 273 participants; moderate-certainty evidence); and there were fewer hospitalisations due to respiratory exacerbations with levofloxacin compared to tobramycin (RR 0.62, 95% CI 0.40 to 0.98; 1 trial, 282 participants; high-certainty evidence). Important treatment-related adverse events were not very common across comparisons, but were reported less often in the tobramycin group compared to both aztreonam lysine and colistimethate. We found the certainty of evidence for these comparisons to be directly related to the risk of bias within the individual trials and varied from low to high. AUTHORS' CONCLUSIONS Long-term treatment with inhaled anti-pseudomonal antibiotics probably improves lung function and reduces exacerbation rates, but pooled estimates of the level of benefit were very limited. The best evidence available is for inhaled tobramycin. More evidence from trials measuring similar outcomes in the same way is needed to determine a better measure of benefit. Longer-term trials are needed to look at the effect of inhaled antibiotics on quality of life, survival and nutritional outcomes.
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Affiliation(s)
- Sherie Smith
- Division of Child Health, Obstetrics & Gynaecology (COG), School of Medicine, University of Nottingham, Nottingham, UK
| | - Nicola J Rowbotham
- Division of Child Health, Obstetrics & Gynaecology (COG), School of Medicine, University of Nottingham, Nottingham, UK
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Antibiotics Drive Expansion of Rare Pathogens in a Chronic Infection Microbiome Model. mSphere 2022; 7:e0031822. [PMID: 35972133 PMCID: PMC9599657 DOI: 10.1128/msphere.00318-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chronic (long-lasting) infections are globally a major and rising cause of morbidity and mortality. Unlike typical acute infections, chronic infections are ecologically diverse, characterized by the presence of a polymicrobial mix of opportunistic pathogens and human-associated commensals. To address the challenge of chronic infection microbiomes, we focus on a particularly well-characterized disease, cystic fibrosis (CF), where polymicrobial lung infections persist for decades despite frequent exposure to antibiotics. Epidemiological analyses point to conflicting results on the benefits of antibiotic treatment yet are confounded by the dependency of antibiotic exposures on prior pathogen presence, limiting their ability to draw causal inferences on the relationships between antibiotic exposure and pathogen dynamics. To address this limitation, we develop a synthetic infection microbiome model representing CF metacommunity diversity and benchmark on clinical data. We show that in the absence of antibiotics, replicate microbiome structures in a synthetic sputum medium are highly repeatable and dominated by oral commensals. In contrast, challenge with physiologically relevant antibiotic doses leads to substantial community perturbation characterized by multiple alternate pathogen-dominant states and enrichment of drug-resistant species. These results provide evidence that antibiotics can drive the expansion (via competitive release) of previously rare opportunistic pathogens and offer a path toward microbiome-informed conditional treatment strategies. IMPORTANCE We develop and clinically benchmark an experimental model of the cystic fibrosis (CF) lung infection microbiome to investigate the impacts of antibiotic exposures on chronic, polymicrobial infections. We show that a single experimental model defined by metacommunity data can partially recapitulate the diversity of individual microbiome states observed across a population of people with CF. In the absence of antibiotics, we see highly repeatable community structures, dominated by oral microbes. Under clinically relevant antibiotic exposures, we see diverse and frequently pathogen-dominated communities, and a nonevolutionary enrichment of antimicrobial resistance on the community scale, mediated by competitive release. The results highlight the potential importance of nonevolutionary (community-ecological) processes in driving the growing global crisis of increasing antibiotic resistance.
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Abstract
BACKGROUND Cystic fibrosis is a genetic disorder in which abnormal mucus in the lungs is associated with susceptibility to persistent infection. Pulmonary exacerbations are when symptoms of infection become more severe. Antibiotics are an essential part of treatment for exacerbations and inhaled antibiotics may be used alone or in conjunction with oral antibiotics for milder exacerbations or with intravenous antibiotics for more severe infections. Inhaled antibiotics do not cause the same adverse effects as intravenous antibiotics and may prove an alternative in people with poor access to their veins. This is an update of a previously published review. OBJECTIVES To determine if treatment of pulmonary exacerbations with inhaled antibiotics in people with cystic fibrosis improves their quality of life, reduces time off school or work, and improves their long-term lung function. SEARCH METHODS We searched the Cochrane Cystic Fibrosis Group's Cystic Fibrosis Trials Register. Date of the last search: 7 March 2022. We also searched ClinicalTrials.gov, the Australia and New Zealand Clinical Trials Registry and WHO ICTRP for relevant trials. Date of last search: 3 May 2022. SELECTION CRITERIA Randomised controlled trials in people with cystic fibrosis with a pulmonary exacerbation in whom treatment with inhaled antibiotics was compared to placebo, standard treatment or another inhaled antibiotic for between one and four weeks. DATA COLLECTION AND ANALYSIS Two review authors independently selected eligible trials, assessed the risk of bias in each trial and extracted data. They assessed the certainty of the evidence using the GRADE criteria. Authors of the included trials were contacted for more information. MAIN RESULTS Five trials with 183 participants are included in the review. Two trials (77 participants) compared inhaled antibiotics alone to intravenous antibiotics alone and three trials (106 participants) compared a combination of inhaled and intravenous antibiotics to intravenous antibiotics alone. Trials were heterogenous in design and two were only available in abstract form. Risk of bias was difficult to assess in most trials but, for four out of five trials, we judged there to be a high risk from lack of blinding and an unclear risk with regards to randomisation. Results were not fully reported and only limited data were available for analysis. One trial was a cross-over design and we only included data from the first intervention arm. Inhaled antibiotics alone versus intravenous antibiotics alone Only one trial (18 participants) reported a perceived improvement in lifestyle (quality of life) in both groups (very low-certainty evidence). Neither trial reported on time off work or school. Both trials measured lung function, but there was no difference reported between treatment groups (very low-certainty evidence). With regards to our secondary outcomes, one trial (18 participants) reported no difference in the need for additional antibiotics and the second trial (59 participants) reported on the time to next exacerbation. In neither case was a difference between treatments identified (both very low-certainty evidence). The single trial (18 participants) measuring adverse events and sputum microbiology did not observe any in either treatment group for either outcome (very low-certainty evidence). Inhaled antibiotics plus intravenous antibiotics versus intravenous antibiotics alone Inhaled antibiotics plus intravenous antibiotics may make little or no difference to quality of life compared to intravenous antibiotics alone. None of the trials reported time off work or school. All three trials measured lung function, but found no difference between groups in forced expiratory volume in one second (two trials; 44 participants; very low-certainty evidence) or vital capacity (one trial; 62 participants). None of the trials reported on the need for additional antibiotics. Inhaled plus intravenous antibiotics may make little difference to the time to next exacerbation; however, one trial (28 participants) reported on hospital admissions and found no difference between groups. There is likely no difference between groups in adverse events (very low-certainty evidence) and one trial (62 participants) reported no difference in the emergence of antibiotic-resistant organisms (very low-certainty evidence). AUTHORS' CONCLUSIONS We identified only low- or very low-certainty evidence to judge the effectiveness of inhaled antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis. The included trials were not sufficiently powered to achieve their goals. Hence, we are unable to demonstrate whether one treatment was superior to the other or not. Further research is needed to establish whether inhaled tobramycin may be used as an alternative to intravenous tobramycin for some pulmonary exacerbations.
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Affiliation(s)
- Sherie Smith
- Division of Child Health, Obstetrics & Gynaecology (COG), School of Medicine, University of Nottingham, Nottingham, UK
| | - Nicola J Rowbotham
- Division of Child Health, Obstetrics & Gynaecology, School of Medicine, The University of Nottingham, Nottingham, UK
| | - Edward Charbek
- Division of Pulmonary, Critical Care and Sleep Medicine, St Louis University School of Medicine, St Louis, MO, USA
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Simulated intravenous versus inhaled tobramycin with and without intravenous ceftazidime evaluated against hypermutable Pseudomonas aeruginosa via a dynamic biofilm model and mechanism-based modeling. Antimicrob Agents Chemother 2022; 66:e0220321. [PMID: 35041509 DOI: 10.1128/aac.02203-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acute exacerbations of chronic respiratory infections in patients with cystic fibrosis are highly challenging due to hypermutable Pseudomonas aeruginosa, biofilm formation and resistance emergence. We aimed to systematically evaluate the effects of intravenous versus inhaled tobramycin with and without intravenous ceftazidime. Two hypermutable P. aeruginosa isolates, CW30 (MICCAZ 0.5mg/L, MICTOB 2mg/L) and CW8 (MICCAZ 2mg/L, MICTOB 8mg/L), were investigated for 120h in dynamic in vitro biofilm studies. Treatments were: intravenous ceftazidime 9g/day (33% lung fluid penetration); intravenous tobramycin 10mg/kg 24-hourly (50% lung fluid penetration); inhaled tobramycin 300mg 12-hourly, and both ceftazidime-tobramycin combinations. Total and less-susceptible planktonic and biofilm bacteria were quantified over 120h. Mechanism-based modeling was performed. All monotherapies were ineffective for both isolates, with regrowth of planktonic (≥4.7log10 CFU/mL) and biofilm (>3.8log10 CFU/cm2) bacteria, and resistance amplification by 120h. Both combination treatments demonstrated synergistic or enhanced bacterial killing of planktonic and biofilm bacteria. With the combination simulating tobramycin inhalation, planktonic bacterial counts of the two isolates at 120h were 0.47% and 36% of those for the combination with intravenous tobramycin; for biofilm bacteria the corresponding values were 8.2% and 13%. Combination regimens achieved substantial suppression of resistance of planktonic and biofilm bacteria compared to each antibiotic in monotherapy for both isolates. Mechanism-based modeling well described all planktonic and biofilm counts, and indicated synergy of the combination regimens despite reduced activity of tobramycin in biofilm. Combination regimens of inhaled tobramycin with ceftazidime hold promise to treat acute exacerbations caused by hypermutable P. aeruginosa strains and warrant further investigation.
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Computationally designed pyocyanin demethylase acts synergistically with tobramycin to kill recalcitrant Pseudomonas aeruginosa biofilms. Proc Natl Acad Sci U S A 2021; 118:2022012118. [PMID: 33723058 DOI: 10.1073/pnas.2022012118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that develops difficult-to-treat biofilms in immunocompromised individuals, cystic fibrosis patients, and in chronic wounds. P. aeruginosa has an arsenal of physiological attributes that enable it to evade standard antibiotic treatments, particularly in the context of biofilms where it grows slowly and becomes tolerant to many drugs. One of its survival strategies involves the production of the redox-active phenazine, pyocyanin, which promotes biofilm development. We previously identified an enzyme, PodA, that demethylated pyocyanin and disrupted P. aeruginosa biofilm development in vitro. Here, we asked if this protein could be used as a potential therapeutic for P. aeruginosa infections together with tobramycin, an antibiotic typically used in the clinic. A major roadblock to answering this question was the poor yield and stability of wild-type PodA purified from standard Escherichia coli overexpression systems. We hypothesized that the insufficient yields were due to poor packing within PodA's obligatory homotrimeric interfaces. We therefore applied the protein design algorithm, AffiLib, to optimize the symmetric core of this interface, resulting in a design that incorporated five mutations leading to a 20-fold increase in protein yield from heterologous expression and purification and a substantial increase in stability to environmental conditions. The addition of the designed PodA with tobramycin led to increased killing of P. aeruginosa cultures under oxic and hypoxic conditions in both the planktonic and biofilm states. This study highlights the potential for targeting extracellular metabolites to assist the control of P. aeruginosa biofilms that tolerate conventional antibiotic treatment.
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Pourtois JD, Kratochvil MJ, Chen Q, Haddock NL, Burgener EB, De Leo GA, Bollyky PL. Filamentous Bacteriophages and the Competitive Interaction between Pseudomonas aeruginosa Strains under Antibiotic Treatment: a Modeling Study. mSystems 2021; 6:e0019321. [PMID: 34156288 PMCID: PMC8269214 DOI: 10.1128/msystems.00193-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/24/2021] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa (Pa) is a major bacterial pathogen responsible for chronic lung infections in cystic fibrosis patients. Recent work has implicated Pf bacteriophages, nonlytic filamentous viruses produced by Pa, in the chronicity and severity of Pa infections. Pf phages act as structural elements in Pa biofilms and sequester aerosolized antibiotics, thereby contributing to antibiotic tolerance. Consistent with a selective advantage in this setting, the prevalence of Pf-positive (Pf+) bacteria increases over time in these patients. However, the production of Pf phages comes at a metabolic cost to bacteria, such that Pf+ strains grow more slowly than Pf-negative (Pf-) strains in vitro. Here, we use a mathematical model to investigate how these competing pressures might influence the relative abundance of Pf+ versus Pf- strains in different settings. Our model suggests that Pf+ strains of Pa cannot outcompete Pf- strains if the benefits of phage production falls onto both Pf+ and Pf- strains for a majority of parameter combinations. Further, phage production leads to a net positive gain in fitness only at antibiotic concentrations slightly above the MIC (i.e., concentrations for which the benefits of antibiotic sequestration outweigh the metabolic cost of phage production) but which are not lethal for Pf+ strains. As a result, our model suggests that frequent administration of intermediate doses of antibiotics with low decay rates and high killing rates favors Pf+ over Pf- strains. These models inform our understanding of the ecology of Pf phages and suggest potential treatment strategies for Pf+ Pa infections. IMPORTANCE Filamentous phages are a frontier in bacterial pathogenesis, but the impact of these phages on bacterial fitness is unclear. In particular, Pf phages produced by Pa promote antibiotic tolerance but are metabolically expensive to produce, suggesting that competing pressures may influence the prevalence of Pf+ versus Pf- strains of Pa in different settings. Our results identify conditions likely to favor Pf+ strains and thus antibiotic tolerance. This study contributes to a better understanding of the unique ecology of filamentous phages in both environmental and clinical settings and may facilitate improved treatment strategies for combating antibiotic tolerance.
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Affiliation(s)
- Julie D. Pourtois
- Department of Biology, Stanford University, Stanford, California, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Michael J. Kratochvil
- Department of Materials Science and Engineering, Stanford University, Stanford, California, USA
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Qingquan Chen
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Naomi L. Haddock
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Elizabeth B. Burgener
- Center for Excellence in Pulmonary Biology, Department of Pediatrics, Stanford University, Stanford, California, USA
| | - Giulio A. De Leo
- Department of Biology, Stanford University, Stanford, California, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
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The Quorum-Sensing Inhibitor Furanone C-30 Rapidly Loses Its Tobramycin-Potentiating Activity against Pseudomonas aeruginosa Biofilms during Experimental Evolution. Antimicrob Agents Chemother 2021; 65:e0041321. [PMID: 33903100 DOI: 10.1128/aac.00413-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The use of quorum-sensing inhibitors (QSI) has been proposed as an alternative strategy to combat antibiotic resistance. QSI reduce the virulence of a pathogen without killing it and it is claimed that resistance to such compounds is less likely to develop, although there is a lack of experimental data supporting this hypothesis. Additionally, such studies are often carried out in conditions that do not mimic the in vivo situation. In the present study, we evaluated whether a combination of the QSI furanone C-30 and the aminoglycoside antibiotic tobramycin would be "evolution-proof" when used to eradicate Pseudomonas aeruginosa biofilms grown in a synthetic cystic fibrosis sputum medium. We found that the biofilm-eradicating activity of the tobramycin/furanone C-30 combination already decreased after 5 treatment cycles. The antimicrobial susceptibility of P. aeruginosa to tobramycin decreased 8-fold after 16 cycles of treatment with the tobramycin/furanone C-30 combination. Furthermore, microcalorimetry revealed changes in the metabolic activity of P. aeruginosa exposed to furanone C-30, tobramycin, and the combination. Whole-genome sequencing analysis of the evolved strains exposed to the combination identified mutations in mexT, fusA1, and parS, genes known to be involved in antibiotic resistance. In P. aeruginosa treated with furanone C-30 alone, a deletion in mexT was also observed. Our data indicate that furanone C-30 is not "evolution-proof" and quickly becomes ineffective as a tobramycin potentiator.
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16
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Pharmacokinetic and Pharmacodynamic Optimization of Antibiotic Therapy in Cystic Fibrosis Patients: Current Evidences, Gaps in Knowledge and Future Directions. Clin Pharmacokinet 2021; 60:409-445. [PMID: 33486720 DOI: 10.1007/s40262-020-00981-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2020] [Indexed: 10/22/2022]
Abstract
Antibiotic therapy is one of the main treatments for cystic fibrosis (CF). It aims to eradicate bacteria during early infection, calms down the inflammatory process, and leads to symptom resolution of pulmonary exacerbations. CF can modify both the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of antibiotics, therefore specific PK/PD endpoints should be determined in the context of CF. Currently available data suggest that optimal PK/PD targets cannot be attained in sputum with intravenous aminoglycosides. Continuous infusion appears preferable for β-lactam antibiotics, but optimal concentrations in sputum are unlikely to be reached, with some possible exceptions such as meropenem and ceftolozane. Usual doses are likely suboptimal for fluoroquinolones and linezolid, whereas daily doses of 45-60 mg/kg and 200 mg could be convenient for vancomycin and doxycycline, respectively. Weekly azithromycin doses of 22-30 mg/kg could also be appropriate for its anti-inflammatory effect. The difficulty with achieving optimal concentrations supports the use of combined treatments and the inhaled administration route, as very high local concentrations, concomitantly with low systemic exposure, can be obtained with the inhaled route for aminoglycosides, colistin, and fluoroquinolones, thus minimizing the risk of toxicity.
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17
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Liquid Chromatography Mass Spectrometry Detection of Antibiotic Agents in Sputum from Persons with Cystic Fibrosis. Antimicrob Agents Chemother 2021; 65:AAC.00927-20. [PMID: 33139284 DOI: 10.1128/aac.00927-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/12/2020] [Indexed: 11/20/2022] Open
Abstract
Antibiotic therapy is expected to impact host microbial communities considerably, yet many studies focused on microbiome and health are often confounded by limited information about antibiotic exposure. Given that antibiotics have diverse pharmacokinetic and antimicrobial properties, investigating the type and concentration of these agents in specific host specimens would provide much needed insight into their impact on the microbes therein. Here, we developed liquid chromatography mass spectrometry (LC-MS) methods to detect 18 antibiotic agents in sputum from persons with cystic fibrosis. Antibiotic spike-in control samples were used to compare three liquid extraction methods on the Waters Acquity Quattro Premier XE. Extraction with dithiothreitol captured the most antibiotics and was used to detect antibiotics in sputum samples from 11 people with cystic fibrosis, with results being compared to the individuals' self-reported antibiotic use. For the sputum samples, two LC-MS assays were used; the Quattro Premier detected nanomolar or micromolar concentrations of 16 antibiotics, whereas the Xevo TQ-XS detected all 18 antibiotics, most at subnanomolar levels. In 45% of tested sputum samples (71/158), at least one antibiotic that was not reported by the subject was detected by both LC-MS methods, a discordance largely explained by the thrice weekly administration and long half-life of azithromycin. For ∼37% of samples, antibiotics reported as taken by the individual were not detected by either instrument. Our results provide an approach for detecting a variety of antibiotics at the site of infection, thereby providing a means to include antibiotic usage data into microbiome studies.
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18
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Rouillard KR, Novak OP, Pistiolis AM, Yang L, Ahonen MJR, McDonald RA, Schoenfisch MH. Exogenous Nitric Oxide Improves Antibiotic Susceptibility in Resistant Bacteria. ACS Infect Dis 2021; 7:23-33. [PMID: 33291868 DOI: 10.1021/acsinfecdis.0c00337] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Antibiotic resistance in bacteria is a major global threat and a leading cause for healthcare-related morbidity and mortality. Resistant biofilm infections are particularly difficult to treat owing to the protective biofilm matrix, which decreases both antibiotic efficacy and clearance by the host. Novel antimicrobial agents that are capable of eradicating resistant infections are greatly needed to combat the rise of antibiotic-resistant bacteria, particularly in patients with cystic fibrosis who are frequently colonized by multidrug-resistant species. Our research group has developed nitric oxide-releasing biopolymers as alternatives to conventional antibiotics. Here, we show that nitric oxide acts as a broad-spectrum antibacterial agent while also improving the efficacy of conventional antibiotics when delivered sequentially. Alone, nitric oxide kills a broad range of bacteria in planktonic and biofilm form without engendering resistance. In combination with conventional antibiotics, nitric oxide increases bacterial susceptibility to multiple classes of antibiotics and slows the development of antibiotic resistance. We anticipate that the use of nitric oxide in combination with antibiotics may improve the outcome of patients with refractory infections, particularly those that are multidrug-resistant.
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Affiliation(s)
- Kaitlyn R. Rouillard
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Olivia P. Novak
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Alex M. Pistiolis
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Lei Yang
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Mona J. R. Ahonen
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Vast Therapeutics, Durham, North Carolina 27703, United States
| | | | - Mark H. Schoenfisch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Vast Therapeutics, Durham, North Carolina 27703, United States
- Division of Pharmacoengineering and Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, Chapel Hill, North Carolina 27599, United States
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Soares A, Alexandre K, Etienne M. Tolerance and Persistence of Pseudomonas aeruginosa in Biofilms Exposed to Antibiotics: Molecular Mechanisms, Antibiotic Strategies and Therapeutic Perspectives. Front Microbiol 2020; 11:2057. [PMID: 32973737 PMCID: PMC7481396 DOI: 10.3389/fmicb.2020.02057] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/05/2020] [Indexed: 01/19/2023] Open
Abstract
Pseudomonas aeruginosa biofilm-related infections are difficult to treat with antibiotics. Along the different layers of the biofilm, the P. aeruginosa population is heterogeneous, exhibiting an extreme ability to adapt his metabolic activity to the local microenvironment. At the deepest layers of the biofilm is a subset of dormant cells, called persister cells. Though antimicrobial failure might be multifactorial, it is now demonstrated that these persister cells, genetically identical to a fully susceptible strain, but phenotypically divergent, are highly tolerant to antibiotics, and contribute to antimicrobial failure. By eradicating susceptible, metabolically active cells, antibiotics bring out pre-existing persister cells. The biofilm mode of growth creates microenvironment conditions that activate stringent response mechanisms, SOS response and toxin-antitoxin systems that render the bacterial population highly tolerant to antibiotics. Using diverse, not standardized, models of biofilm infection, a large panel of antibiotic regimen has been evaluated. They demonstrated that biofilm growth had an unequal impact of antibiotic activity, colistin and meropenem being the less impacted antibiotics. Different combination and sequential antimicrobial therapies were also evaluated, and could be partially efficient, but none succeeded in eradicating persister cells, so that non-antibiotic alternative strategies are currently under development. This article reviews the molecular mechanisms involved in antibiotic tolerance and persistence in P. aeruginosa biofilm infections. A review of the antimicrobial regimen evaluated for the treatment of P. aeruginosa biofilm infection is also presented. While tremendous progress has been made in the understanding of biofilm-related infections, alternative non-antibiotic strategies are now urgently needed.
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Affiliation(s)
- Anaïs Soares
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France
| | - Kévin Alexandre
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
| | - Manuel Etienne
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
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20
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Abstract
BACKGROUND Cystic fibrosis is a genetic disorder in which abnormal mucus in the lungs is associated with susceptibility to persistent infection. Pulmonary exacerbations are when symptoms of infection become more severe. Antibiotics are an essential part of treatment for exacerbations and inhaled antibiotics may be used alone or in conjunction with oral antibiotics for milder exacerbations or with intravenous antibiotics for more severe infections. Inhaled antibiotics do not cause the same adverse effects as intravenous antibiotics and may prove an alternative in people with poor access to their veins. This is an update of a previously published review. OBJECTIVES To determine if treatment of pulmonary exacerbations with inhaled antibiotics in people with cystic fibrosis improves their quality of life, reduces time off school or work and improves their long-term survival. SEARCH METHODS We searched the Cochrane Cystic Fibrosis Group's Cystic Fibrosis Trials Register. Date of the last search: 03 October 2018.We searched ClinicalTrials.gov, the Australia and New Zealand Clinical Trials Registry and WHO ICTRP for relevant trials. Date of last search: 09 October 2018. SELECTION CRITERIA Randomised controlled trials in people with cystic fibrosis with a pulmonary exacerbation in whom treatment with inhaled antibiotics was compared to placebo, standard treatment or another inhaled antibiotic for between one and four weeks. DATA COLLECTION AND ANALYSIS Two review authors independently selected eligible trials, assessed the risk of bias in each trial and extracted data. They assessed the quality of the evidence using the GRADE criteria. Authors of the included trials were contacted for more information. MAIN RESULTS Four trials with 167 participants are included in the review. Two trials (77 participants) compared inhaled antibiotics alone to intravenous antibiotics alone and two trials (90 participants) compared a combination of inhaled and intravenous antibiotics to intravenous antibiotics alone. Trials were heterogenous in design and two were only available in abstract form. Risk of bias was difficult to assess in most trials, but for all trials we judged there to be a high risk from lack of blinding and an unclear risk with regards to randomisation. Results were not fully reported and only limited data were available for analysis.Inhaled antibiotics alone versus intravenous antibiotics aloneOnly one trial (n = 18) reported a perceived improvement in lifestyle (quality of life) in both groups (very low-quality of evidence). Neither trial reported on time off work or school. Both trials measured lung function, but there was no difference reported between treatment groups (very low-quality evidence). With regards to our secondary outcomes, one trial (n = 18) reported no difference in the need for additional antibiotics and the second trial (n = 59) reported on the time to next exacerbation. In neither case was a difference between treatments identified (both very low-quality evidence). The single trial (n = 18) measuring adverse events and sputum microbiology did not observe any in either treatment group for either outcome (very low-quality evidence).Inhaled antibiotics plus intravenous antibiotics versus intravenous antibiotics aloneNeither trial reported on quality of life or time off work or school. Both trials measured lung function, but found no difference between groups in forced expiratory volume in one second (one trial, n = 28, very low-quality evidence) or vital capacity (one trial, n = 62). Neither trial reported on the need for additional antibiotics or the time to the next exacerbation; however, one trial (n = 28) reported on hospital admissions and found no difference between groups. Both trials reported no difference between groups in adverse events (very low-quality evidence) and one trial (n = 62) reported no difference in the emergence of antibiotic-resistant organisms (very low-quality evidence). AUTHORS' CONCLUSIONS There is little useful high-level evidence to judge the effectiveness of inhaled antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis. The included trials were not sufficiently powered to achieve their goals. Hence, we are unable to demonstrate whether one treatment was superior to the other or not. Further research is needed to establish whether inhaled tobramycin may be used as an alternative to intravenous tobramycin for some pulmonary exacerbations.
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Affiliation(s)
- Sherie Smith
- The University of NottinghamDivision of Child Health, Obstetrics & Gynaecology, School of Medicine1701 E FloorEast Block Queens Medical CentreNottinghamNG7 2UHUK
| | - Nicola J Rowbotham
- The University of NottinghamDivision of Child Health, Obstetrics & Gynaecology, School of Medicine1701 E FloorEast Block Queens Medical CentreNottinghamNG7 2UHUK
| | - Edward Charbek
- St Louis University School of MedicineDivision of Pulmonary, Critical Care and Sleep Medicine1402 S. Grand Ave, 7‐S‐FDTSt LouisMOUSA63104‐1004
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Bos AC, Mouton JW, van Westreenen M, Andrinopoulou ER, Janssens HM, Tiddens HAWM. Patient-specific modelling of regional tobramycin concentration levels in airways of patients with cystic fibrosis: can we dose once daily? J Antimicrob Chemother 2018; 72:3435-3442. [PMID: 29029057 DOI: 10.1093/jac/dkx293] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 07/18/2017] [Indexed: 01/28/2023] Open
Abstract
Background Inhaled tobramycin is important in the treatment of Pseudomonas aeruginosa (Pa) infections in cystic fibrosis (CF). However, despite its use it fails to attenuate the clinical progression of CF lung disease. The bactericidal efficacy of tobramycin is known to be concentration-dependent and hence changing the dosing regimen from a twice-daily (q12h) inhalation to a once-daily (q24h) inhaled double dose could improve treatment outcomes. Objectives To predict local concentrations of nebulized tobramycin in the airways of patients with CF, delivered with the small airway-targeting Akita® system or standard PARI-LC® Plus system, with different inspiratory flow profiles. Methods Computational fluid dynamic (CFD) methods were applied to patient-specific airway models reconstructed from chest CT scans. The following q12h and q24h dosing regimens were evaluated: Akita® (150 and 300 mg) and PARI-LC® Plus (300 and 600 mg). Site-specific concentrations were calculated. Results Twelve CT scans from patients aged 12-17 years (median = 15.7) were selected. Small airway concentrations were 762-2999 mg/L for the q12h dosing regimen and 1523-5997 mg/L for the q24h dosing regimen, well above the MIC for WT Pa strains. Importantly, the q24h regimen appeared to be more suitable than the q12h regimen against more resistant Pa strains and the inhibitory effects of sputum on tobramycin activity. Conclusions CFD modelling showed that high concentrations of inhaled tobramycin are indeed delivered to the airways, with the Akita® system being twice as efficient as the PARI-LC® system. Ultimately, the q24h dosing regimen appears more effective against subpopulations with high MICs (i.e. more resistant strains).
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Affiliation(s)
- Aukje C Bos
- Department of Pediatric Pulmonology, Erasmus Medical Centre (MC)-Sophia Children's Hospital, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands.,Department of Radiology, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Mireille van Westreenen
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | | | - Hettie M Janssens
- Department of Pediatric Pulmonology, Erasmus Medical Centre (MC)-Sophia Children's Hospital, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Harm A W M Tiddens
- Department of Pediatric Pulmonology, Erasmus Medical Centre (MC)-Sophia Children's Hospital, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands.,Department of Radiology, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
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22
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Smith S, Rowbotham NJ, Regan KH. Inhaled anti-pseudomonal antibiotics for long-term therapy in cystic fibrosis. Cochrane Database Syst Rev 2018; 3:CD001021. [PMID: 29607494 PMCID: PMC8407188 DOI: 10.1002/14651858.cd001021.pub3] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Inhaled antibiotics are commonly used to treat persistent airway infection with Pseudomonas aeruginosa that contributes to lung damage in people with cystic fibrosis. Current guidelines recommend inhaled tobramycin for individuals with cystic fibrosis and persistent Pseudomonas aeruginosa infection who are aged six years or older. The aim is to reduce bacterial load in the lungs so as to reduce inflammation and deterioration of lung function. This is an update of a previously published review. OBJECTIVES To evaluate the effects long-term inhaled antibiotic therapy in people with cystic fibrosis on clinical outcomes (lung function, frequency of exacerbations and nutrition), quality of life and adverse events (including drug sensitivity reactions and survival). SEARCH METHODS We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched ongoing trials registries.Date of last search: 13 February 2018. SELECTION CRITERIA We selected trials if inhaled anti-pseudomonal antibiotic treatment was used for at least three months in people with cystic fibrosis, treatment allocation was randomised or quasi-randomised, and there was a control group (either placebo, no placebo or another inhaled antibiotic). DATA COLLECTION AND ANALYSIS Two authors independently selected trials, judged the risk of bias, extracted data from these trials and judged the quality of the evidence using the GRADE system. MAIN RESULTS The searches identified 333 citations to 98 trials; 18 trials (3042 participants aged between five and 56 years) met the inclusion criteria. Limited data were available for meta-analyses due to the variability of trial design and reporting of results. A total of 11 trials (1130 participants) compared an inhaled antibiotic to placebo or usual treatment for a duration between three and 33 months. Five trials (1255 participants) compared different antibiotics, two trials (585 participants) compared different regimens of tobramycin and one trial (90 participants) compared intermittent tobramycin with continuous tobramycin alternating with aztreonam. One of the trials (18 participants) compared to placebo and a different antibiotic and so fell into both groups. The most commonly studied antibiotic was tobramycin which was studied in 12 trials.We found limited evidence that inhaled antibiotics improved lung function (four of the 11 placebo-controlled trials, n = 814). Compared to placebo, inhaled antibiotics also reduced the frequency of exacerbations (three trials, n = 946), risk ratio 0.66 (95% confidence interval (CI) 0.47 to 0.93). There were insufficient data for us to be able to report an effect on nutritional outcomes or survival and there were insufficient data for us to ascertain the effect on quality of life. There was no significant effect on antibiotic resistance seen in the two trials that were included in meta-analyses. Tinnitus and voice alteration were the only adverse events significantly more common in the inhaled antibiotics group. The overall quality of evidence was deemed to be low for most outcomes due to risk of bias within the trials and imprecision due to low event rates.Of the eight trials that compared different inhaled antibiotics or different antibiotic regimens, there was only one trial in each comparison. Forced expiratory volume at one second (FEV1) % predicted was only found to be significantly improved with aztreonam lysine for inhalation compared to tobramycin (n = 273), mean difference -3.40% (95% CI -6.63 to -0.17). However, the method of defining the endpoint was different to the remaining trials and the participants were exposed to tobramycin for a long period making interpretation of the results problematic. No significant differences were found in the remaining comparisons with regard to lung function. Pulmonary exacerbations were measured in different ways, but one trial (n = 273) found that the number of people treated with antibiotics was lower in those receiving aztreonam than tobramycin, risk ratio 0.66 (95% CI 0.51 to 0.86). We found the quality of evidence for these comparisons to be directly related to the risk of bias within the individual trials and varied from low to high. AUTHORS' CONCLUSIONS Inhaled anti-pseudomonal antibiotic treatment probably improves lung function and reduces exacerbation rate, but pooled estimates of the level of benefit were very limited. The best evidence is for inhaled tobramycin. More evidence from trials measuring similar outcomes in the same way is needed to determine a better measure of benefit. Longer-term trials are needed to look at the effect of inhaled antibiotics on quality of life, survival and nutritional outcomes.
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Affiliation(s)
- Sherie Smith
- The University of NottinghamDivision of Child Health, Obstetrics & Gynaecology, School of Medicine1701 E FloorEast Block Queens Medical CentreNottinghamNG7 2UHUK
| | - Nicola J Rowbotham
- The University of NottinghamDivision of Child Health, Obstetrics & Gynaecology, School of Medicine1701 E FloorEast Block Queens Medical CentreNottinghamNG7 2UHUK
| | - Kate H Regan
- NHS LothianRoyal Infirmary of Edinburgh51 Little France CrescentEdinburghUKEH16 4SA
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23
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Antimicrobial molecules in the lung: formulation challenges and future directions for innovation. Future Med Chem 2018; 10:575-604. [PMID: 29473765 DOI: 10.4155/fmc-2017-0162] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Inhaled antimicrobials have been extremely beneficial in treating respiratory infections, particularly chronic infections in a lung with cystic fibrosis. The pulmonary delivery of antibiotics has been demonstrated to improve treatment efficacy, reduce systemic side effects and, critically, reduce drug exposure to commensal bacteria compared with systemic administration, reducing selective pressure for antimicrobial resistance. This review will explore the specific challenges of pulmonary delivery of a number of differing antimicrobial molecules, and the formulation and technological approaches that have been used to overcome these difficulties. It will also explore the future challenges being faced in the development of inhaled products and respiratory infection treatment, and identify future directions of innovation, with a particular focus on respiratory infections caused by multiple drug-resistant pathogens.
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An Antipersister Strategy for Treatment of Chronic Pseudomonas aeruginosa Infections. Antimicrob Agents Chemother 2017; 61:AAC.00987-17. [PMID: 28923873 DOI: 10.1128/aac.00987-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 09/08/2017] [Indexed: 12/21/2022] Open
Abstract
Bacterial persisters are a quasidormant subpopulation of cells that are tolerant to antibiotic treatment. The combination of the aminoglycoside tobramycin with fumarate as an antibacterial potentiator utilizes an antipersister strategy that is aimed at reducing recurrent Pseudomonas aeruginosa infections by enhancing the killing of P. aeruginosa persisters. Stationary-phase cultures of P. aeruginosa were used to generate persister cells. A range of tobramycin concentrations was tested with a range of metabolite concentrations to determine the potentiation effect of the metabolite under a variety of conditions, including a range of pH values and in the presence of azithromycin or cystic fibrosis (CF) patient sputum. In addition, 96-well dish biofilm and colony biofilm assays were performed, and the cytotoxicity of the tobramycin-fumarate combination was determined utilizing a lactate dehydrogenase (LDH) assay. Enhanced killing of up to 6 orders of magnitude of P. aeruginosa persisters over a range of CF isolates, including mucoid and nonmucoid strains, was observed for the tobramycin-fumarate combination compared to killing with tobramycin alone. Furthermore, significant fumarate-mediated potentiation was seen in the presence of azithromycin or CF patient sputum. Fumarate also reduced the cytotoxicity of tobramycin-treated P. aeruginosa to human epithelial airway cells. Finally, in mucoid and nonmucoid CF isolates, complete eradication of P. aeruginosa biofilm was observed in the colony biofilm assay due to fumarate potentiation. These data suggest that a combination of tobramycin with fumarate as an antibacterial potentiator may be an attractive therapeutic for eliminating recurrent P. aeruginosa infections in CF patients through the eradication of bacterial persisters.
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25
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Radlinski L, Rowe SE, Kartchner LB, Maile R, Cairns BA, Vitko NP, Gode CJ, Lachiewicz AM, Wolfgang MC, Conlon BP. Pseudomonas aeruginosa exoproducts determine antibiotic efficacy against Staphylococcus aureus. PLoS Biol 2017; 15:e2003981. [PMID: 29176757 PMCID: PMC5720819 DOI: 10.1371/journal.pbio.2003981] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 12/07/2017] [Accepted: 11/08/2017] [Indexed: 12/12/2022] Open
Abstract
Chronic coinfections of Staphylococcus aureus and Pseudomonas aeruginosa frequently fail to respond to antibiotic treatment, leading to significant patient morbidity and mortality. Currently, the impact of interspecies interaction on S. aureus antibiotic susceptibility remains poorly understood. In this study, we utilize a panel of P. aeruginosa burn wound and cystic fibrosis (CF) lung isolates to demonstrate that P. aeruginosa alters S. aureus susceptibility to bactericidal antibiotics in a variable, strain-dependent manner and further identify 3 independent interactions responsible for antagonizing or potentiating antibiotic activity against S. aureus. We find that P. aeruginosa LasA endopeptidase potentiates lysis of S. aureus by vancomycin, rhamnolipids facilitate proton-motive force-independent tobramycin uptake, and 2-heptyl-4-hydroxyquinoline N-oxide (HQNO) induces multidrug tolerance in S. aureus through respiratory inhibition and reduction of cellular ATP. We find that the production of each of these factors varies between clinical isolates and corresponds to the capacity of each isolate to alter S. aureus antibiotic susceptibility. Furthermore, we demonstrate that vancomycin treatment of a S. aureus mouse burn infection is potentiated by the presence of a LasA-producing P. aeruginosa population. These findings demonstrate that antibiotic susceptibility is complex and dependent not only upon the genotype of the pathogen being targeted, but also on interactions with other microorganisms in the infection environment. Consideration of these interactions will improve the treatment of polymicrobial infections.
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Affiliation(s)
- Lauren Radlinski
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Sarah E. Rowe
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Laurel B. Kartchner
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States of America
- North Carolina Jaycee Burn Center, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Robert Maile
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States of America
- North Carolina Jaycee Burn Center, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Bruce A. Cairns
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States of America
- North Carolina Jaycee Burn Center, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Nicholas P. Vitko
- Marsico Lung Institute, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Cindy J. Gode
- Marsico Lung Institute, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Anne M. Lachiewicz
- North Carolina Jaycee Burn Center, University of North Carolina at Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Matthew C. Wolfgang
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States of America
- Marsico Lung Institute, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Brian P. Conlon
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States of America
- Marsico Lung Institute, University of North Carolina at Chapel Hill, North Carolina, United States of America
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26
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Langton Hewer SC, Smyth AR. Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis. Cochrane Database Syst Rev 2017; 4:CD004197. [PMID: 28440853 PMCID: PMC6478104 DOI: 10.1002/14651858.cd004197.pub5] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Respiratory tract infection with Pseudomonas aeruginosa occurs in most people with cystic fibrosis. Once chronic infection is established, Pseudomonas aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate.This is an update of a Cochrane review first published in 2003, and previously updated in 2006, 2009 and 2014. OBJECTIVES To determine whether antibiotic treatment of early Pseudomonas aeruginosa infection in children and adults with cystic fibrosis eradicates the organism, delays the onset of chronic infection, and results in clinical improvement. To evaluate whether there is evidence that a particular antibiotic strategy is superior to or more cost-effective than other strategies and to compare the adverse effects of different antibiotic strategies (including respiratory infection with other micro-organisms). SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 10 October 2016. SELECTION CRITERIA We included randomised controlled trials of people with cystic fibrosis, in whom Pseudomonas aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous antibiotics with placebo, usual treatment or other combinations of inhaled, oral or intravenous antibiotics. We excluded non-randomised trials, cross-over trials, and those utilising historical controls. DATA COLLECTION AND ANALYSIS Both authors independently selected trials, assessed risk of bias and extracted data. MAIN RESULTS The search identified 60 trials; seven trials (744 participants) with a duration between 28 days and 27 months were eligible for inclusion. Three of the trials are over 10 years old and their results may be less applicable today given the changes in standard treatment. Some of the trials had low numbers of participants and most had relatively short follow-up periods; however, there was generally a low risk of bias from missing data. In most trials it was difficult to blind participants and clinicians to treatment given the interventions and comparators used. Two trials were supported by the manufacturers of the antibiotic used.Evidence from two trials (38 participants) at the two-month time-point showed treatment of early Pseudomonas aeruginosa infection with inhaled tobramycin results in microbiological eradication of the organism from respiratory secretions more often than placebo, odds ratio 0.15 (95% confidence interval (CI) 0.03 to 0.65) and data from one of these trials, with longer follow up, suggested that this effect may persist for up to 12 months.One randomised controlled trial (26 participants) compared oral ciprofloxacin and nebulised colistin versus usual treatment. Results after two years suggested treatment of early infection results in microbiological eradication of Pseudomonas aeruginosa more often than no anti-pseudomonal treatment, odds ratio 0.12 (95% CI 0.02 to 0.79).One trial comparing 28 days to 56 days treatment with nebulised tobramycin solution for inhalation in 88 participants showed that both treatments were effective and well-tolerated, with no notable additional improvement with longer over shorter duration of therapy. However, this trial was not powered to detect non-inferiority or equivalence .A trial of oral ciprofloxacin with inhaled colistin versus nebulised tobramycin solution for inhalation alone (223 participants) failed to show a difference between the two strategies, although it was underpowered to show this. A further trial of inhaled colistin with oral ciprofloxacin versus nebulised tobramycin solution for inhalation with oral ciprofloxacin also showed no superiority of the former, with increased isolation of Stenotrophomonas maltophilia in both groups.A recent, large trial in 306 children aged between one and 12 years compared cycled nebulised tobramycin solution for inhalation to culture-based therapy and also ciprofloxacin to placebo. The primary analysis showed no difference in time to pulmonary exacerbation or proportion of Pseudomonas aeruginosa positive cultures. An analysis performed in this review (not adjusted for age) showed fewer participants in the cycled therapy group with one or more isolates of Pseudomonas aeruginosa, odds ratio 0.51 (95% CI 0.31 to 0.28). Using GRADE, the quality of evidence for outcomes was downgraded to moderate to very low. Downgrading decisions for Pseudomonas aeruginosa eradication and lung function were based on applicability (participants mostly children) and limitations in study design, with imprecision an additional limitation for lung function, growth parameters and adverse effects. AUTHORS' CONCLUSIONS We found that nebulised antibiotics, alone or in combination with oral antibiotics, were better than no treatment for early infection with Pseudomonas aeruginosa. Eradication may be sustained for up to two years. There is insufficient evidence to determine whether antibiotic strategies for the eradication of early Pseudomonas aeruginosa decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment. Four trials comparing two active treatments have failed to show differences in rates of eradication of Pseudomonas aeruginosa. There have been no published randomised controlled trials that investigate the efficacy of intravenous antibiotics to eradicate Pseudomonas aeruginosa in cystic fibrosis. Overall, there is still insufficient evidence from this review to state which antibiotic strategy should be used for the eradication of early Pseudomonas aeruginosa infection in cystic fibrosis.
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Affiliation(s)
- Simon C Langton Hewer
- Bristol Royal Hospital for ChildrenPaediatric Respiratory MedicineUpper Maudlin StreetBristolAvonUKBS2 8BJ
| | - Alan R Smyth
- School of Medicine, University of NottinghamDivision of Child Health, Obstetrics & Gynaecology (COG)Queens Medical CentreDerby RoadNottinghamUKNG7 2UH
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Meylan S, Porter CBM, Yang JH, Belenky P, Gutierrez A, Lobritz MA, Park J, Kim SH, Moskowitz SM, Collins JJ. Carbon Sources Tune Antibiotic Susceptibility in Pseudomonas aeruginosa via Tricarboxylic Acid Cycle Control. Cell Chem Biol 2017; 24:195-206. [PMID: 28111098 DOI: 10.1016/j.chembiol.2016.12.015] [Citation(s) in RCA: 232] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 11/21/2016] [Accepted: 12/28/2016] [Indexed: 10/20/2022]
Abstract
Metabolically dormant bacteria present a critical challenge to effective antimicrobial therapy because these bacteria are genetically susceptible to antibiotic treatment but phenotypically tolerant. Such tolerance has been attributed to impaired drug uptake, which can be reversed by metabolic stimulation. Here, we evaluate the effects of central carbon metabolite stimulations on aminoglycoside sensitivity in the pathogen Pseudomonas aeruginosa. We identify fumarate as a tobramycin potentiator that activates cellular respiration and generates a proton motive force by stimulating the tricarboxylic acid (TCA) cycle. In contrast, we find that glyoxylate induces phenotypic tolerance by inhibiting cellular respiration with acetyl-coenzyme A diversion through the glyoxylate shunt, despite drug import. Collectively, this work demonstrates that TCA cycle activity is important for both aminoglycoside uptake and downstream lethality and identifies a potential strategy for potentiating aminoglycoside treatment of P. aeruginosa infections.
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Affiliation(s)
- Sylvain Meylan
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA; Department of Biological Engineering, Institute for Medical Engineering & Science, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA; Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Caroline B M Porter
- Department of Biological Engineering, Institute for Medical Engineering & Science, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jason H Yang
- Department of Biological Engineering, Institute for Medical Engineering & Science, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Peter Belenky
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Arnaud Gutierrez
- Department of Biological Engineering, Institute for Medical Engineering & Science, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Michael A Lobritz
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA; Department of Biological Engineering, Institute for Medical Engineering & Science, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Jihye Park
- Department of Pediatrics, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Sun H Kim
- Department of Pediatrics, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Samuel M Moskowitz
- Department of Pediatrics, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - James J Collins
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA; Department of Biological Engineering, Institute for Medical Engineering & Science, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard-MIT Program, Health Sciences and Technology, Cambridge, MA 02139, USA.
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Stenvang M, Dueholm MS, Vad BS, Seviour T, Zeng G, Geifman-Shochat S, Søndergaard MT, Christiansen G, Meyer RL, Kjelleberg S, Nielsen PH, Otzen DE. Epigallocatechin Gallate Remodels Overexpressed Functional Amyloids in Pseudomonas aeruginosa and Increases Biofilm Susceptibility to Antibiotic Treatment. J Biol Chem 2016; 291:26540-26553. [PMID: 27784787 DOI: 10.1074/jbc.m116.739953] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/07/2016] [Indexed: 01/09/2023] Open
Abstract
Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. It has antimicrobial properties and disrupts the ordered structure of amyloid fibrils involved in human disease. The antimicrobial effect of EGCG against the opportunistic pathogen Pseudomonas aeruginosa has been shown to involve disruption of quorum sensing (QS). Functional amyloid fibrils in P. aeruginosa (Fap) are able to bind and retain quorum-sensing molecules, suggesting that EGCG interferes with QS through structural remodeling of amyloid fibrils. Here we show that EGCG inhibits the ability of Fap to form fibrils; instead, EGCG stabilizes protein oligomers. Existing fibrils are remodeled by EGCG into non-amyloid aggregates. This fibril remodeling increases the binding of pyocyanin, demonstrating a mechanism by which EGCG can affect the QS function of functional amyloid. EGCG reduced the amyloid-specific fluorescent thioflavin T signal in P. aeruginosa biofilms at concentrations known to exert an antimicrobial effect. Nanoindentation studies showed that EGCG reduced the stiffness of biofilm containing Fap fibrils but not in biofilm with little Fap. In a combination treatment with EGCG and tobramycin, EGCG had a moderate effect on the minimum bactericidal eradication concentration against wild-type P. aeruginosa biofilms, whereas EGCG had a more pronounced effect when Fap was overexpressed. Our results provide a direct molecular explanation for the ability of EGCG to disrupt P. aeruginosa QS and modify its biofilm and strengthens the case for EGCG as a candidate in multidrug treatment of persistent biofilm infections.
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Affiliation(s)
- Marcel Stenvang
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN).,the Sino-Danish Centre for Education and Research (SDC), 8000 Aarhus C, Denmark
| | - Morten S Dueholm
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | - Brian S Vad
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
| | - Thomas Seviour
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | | | - Susana Geifman-Shochat
- the School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore, and
| | - Mads T Søndergaard
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | | | - Rikke Louise Meyer
- From the Interdisciplinary Nanoscience Center (iNANO).,the Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Staffan Kjelleberg
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore.,the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia
| | - Per Halkjær Nielsen
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark.,the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | - Daniel E Otzen
- From the Interdisciplinary Nanoscience Center (iNANO), .,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
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Khanal A, Sharma R, Corcoran TE, Garoff S, Przybycien TM, Tilton RD. Surfactant Driven Post-Deposition Spreading of Aerosols on Complex Aqueous Subphases. 1: High Deposition Flux Representative of Aerosol Delivery to Large Airways. J Aerosol Med Pulm Drug Deliv 2015; 28:382-93. [PMID: 25723759 DOI: 10.1089/jamp.2014.1168] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Aerosol drug delivery is a viable option for treating diseased airways, but airway obstructions associated with diseases such as cystic fibrosis cause non-uniform drug distribution and limit efficacy. Marangoni stresses produced by surfactant addition to aerosol formulations may enhance delivery uniformity by post-deposition spreading of medications over the airway surface, improving access to poorly ventilated regions. We examine the roles of different variables affecting the maximum post-deposition spreading of a dye (drug mimic). METHODS Entangled aqueous solutions of either poly(acrylamide) (PA) or porcine gastric mucin (PGM) serve as airway surface liquid (ASL) mimicking subphases for in vitro models of aerosol deposition. Measured aerosol deposition fluxes indicate that the experimental delivery conditions are representative of aerosol delivery to the conducting airways. Post-deposition spreading beyond the locale of direct aerosol deposition is tracked by fluorescence microscopy. Aqueous aerosols formulated with either nonionic surfactant (tyloxapol) or fluorosurfactant (FS-3100) are compared with surfactant-free control aerosols. RESULTS Significant enhancement of post-deposition spreading is observed with surfactant solutions relative to surfactant-free control solutions, provided the surfactant solution surface tension is less than that of the subphase. Amongst the variables considered--surfactant concentration, aerosol flow-rate, total deposited volume, time of delivery, and total deposited surfactant mass--surfactant mass is the primary predictor of maximum spread distance. This dependence is also observed for solutions deposited as a single, microliter-scale drop with a volume comparable to the total volume of deposited aerosol. CONCLUSIONS Marangoni stress-assisted spreading after surfactant-laden aerosol deposition at high fluxes on a complex fluid subphase is capable of driving aerosol contents over significantly greater distances compared to surfactant-free controls. Total delivered surfactant mass is the primary determinant of the extent of spreading, suggesting a great potential to extend the reach of aerosolized medication in partially obstructed airways via a purely physical mechanism.
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Affiliation(s)
- Amsul Khanal
- 1 Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,2 Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Ramankur Sharma
- 2 Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,3 Department of Chemical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Timothy E Corcoran
- 1 Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,4 Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Stephen Garoff
- 2 Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,5 Department of Physics, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Todd M Przybycien
- 1 Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,2 Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,3 Department of Chemical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Robert D Tilton
- 1 Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,2 Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,3 Department of Chemical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
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Azithromycin may antagonize inhaled tobramycin when targeting Pseudomonas aeruginosa in cystic fibrosis. Ann Am Thorac Soc 2014; 11:342-50. [PMID: 24476418 DOI: 10.1513/annalsats.201310-352oc] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RATIONALE Recent studies of inhaled tobramycin in subjects with cystic fibrosis (CF) find less clinical improvement than previously observed. Nonhuman data suggest that in some strains of Pseudomonas aeruginosa, azithromycin can antagonize tobramycin. OBJECTIVES We tested the hypothesis that concomitant azithromycin use correlates with less improvement in key outcome measures in subjects receiving inhaled tobramycin while not affecting those receiving a comparative, nonaminoglycoside inhaled antibiotic. METHODS We studied a cohort of 263 subjects with CF enrolled in a recent clinical trial comparing inhaled tobramycin with aztreonam lysine. We performed a secondary analysis to examine key clinical and microbiologic outcomes based on concomitant, chronic azithromycin use at enrollment. MEASUREMENTS AND MAIN RESULTS The cohort randomized to inhaled tobramycin and reporting azithromycin use showed a significant decrease in the percent predicted FEV1 after one and three courses of inhaled tobramycin when compared with those not reporting azithromycin use (28 d: -0.51 vs. 3.43%, P < 0.01; 140 d: -1.87 vs. 6.07%, P < 0.01). Combined azithromycin and inhaled tobramycin use was also associated with earlier need for additional antibiotics, lesser improvement in disease-related quality of life, and a trend toward less reduction in sputum P. aeruginosa density. Subjects randomized to inhaled aztreonam lysine had significantly greater improvement in these outcome measures, which were unaffected by concomitant azithromycin use. Outcomes in those not using azithromycin who received inhaled tobramycin were not significantly different from subjects receiving aztreonam lysine. Azithromycin also antagonized tobramycin but not aztreonam lysine in 40% of P. aeruginosa clinical isolates tested in vitro. CONCLUSIONS Oral azithromycin may antagonize the therapeutic benefits of inhaled tobramycin in subjects with CF with P. aeruginosa airway infection.
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Caceres SM, Malcolm KC, Taylor-Cousar JL, Nichols DP, Saavedra MT, Bratton DL, Moskowitz SM, Burns JL, Nick JA. Enhanced in vitro formation and antibiotic resistance of nonattached Pseudomonas aeruginosa aggregates through incorporation of neutrophil products. Antimicrob Agents Chemother 2014; 58:6851-60. [PMID: 25182651 PMCID: PMC4249413 DOI: 10.1128/aac.03514-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 08/28/2014] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a major pathogen in cystic fibrosis (CF) lung disease. Children with CF are routinely exposed to P. aeruginosa from the natural environment, and by adulthood, 80% of patients are chronically infected. P. aeruginosa in the CF airway exhibits a unique biofilm-like structure, where it grows in small clusters or aggregates of bacteria in association with abundant polymers of neutrophil-derived components F-actin and DNA, among other components. These aggregates differ substantially in size and appearance compared to surface-attached in vitro biofilm models classically utilized for studies but are believed to share properties of surface-attached biofilms, including antibiotic resistance. However, little is known about the formation and function of surface-independent modes of biofilm growth, how they might be eradicated, and quorum sensing communication. To address these issues, we developed a novel in vitro model of P. aeruginosa aggregates incorporating human neutrophil-derived products. Aggregates grown in vitro and those found in CF patients' sputum samples were morphologically similar; viable bacteria were distributed in small pockets throughout the aggregate. The lasA quorum sensing gene was differentially expressed in the presence of neutrophil products. Importantly, aggregates formed in the presence of neutrophils acquired resistance to tobramycin, which was lost when the aggregates were dispersed with DNase, and antagonism of tobramycin and azithromycin was observed. This novel yet simple in vitro system advances our ability to model infection of the CF airway and will be an important tool to study virulence and test alternative eradication strategies against P. aeruginosa.
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Affiliation(s)
- Silvia M Caceres
- Department of Medicine, National Jewish Health, Denver, Colorado, USA
| | - Kenneth C Malcolm
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - Jennifer L Taylor-Cousar
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - David P Nichols
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Pediatrics, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - Milene T Saavedra
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - Donna L Bratton
- Department of Pediatrics, National Jewish Health, Denver, Colorado, USA
| | - Samuel M Moskowitz
- Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jane L Burns
- Division of Pediatric Infectious Disease, Department of Pediatrics, Seattle Children's Hospital, University of Washington School of Medicine, Seattle, Washington, USA
| | - Jerry A Nick
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
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Zhang S, Blount AC, McNicholas CM, Skinner DF, Chestnut M, Kappes JC, Sorscher EJ, Woodworth BA. Resveratrol enhances airway surface liquid depth in sinonasal epithelium by increasing cystic fibrosis transmembrane conductance regulator open probability. PLoS One 2013; 8:e81589. [PMID: 24282612 PMCID: PMC3839872 DOI: 10.1371/journal.pone.0081589] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 10/23/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Chronic rhinosinusitis engenders enormous morbidity in the general population, and is often refractory to medical intervention. Compounds that augment mucociliary clearance in airway epithelia represent a novel treatment strategy for diseases of mucus stasis. A dominant fluid and electrolyte secretory pathway in the nasal airways is governed by the cystic fibrosis transmembrane conductance regulator (CFTR). The objectives of the present study were to test resveratrol, a strong potentiator of CFTR channel open probability, in preparation for a clinical trial of mucociliary activators in human sinus disease. METHODS Primary sinonasal epithelial cells, immortalized bronchoepithelial cells (wild type and F508del CFTR), and HEK293 cells expressing exogenous human CFTR were investigated by Ussing chamber as well as patch clamp technique under non-phosphorylating conditions. Effects on airway surface liquid depth were measured using confocal laser scanning microscopy. Impact on CFTR gene expression was measured by quantitative reverse transcriptase polymerase chain reaction. RESULTS Resveratrol is a robust CFTR channel potentiator in numerous mammalian species. The compound also activated temperature corrected F508del CFTR and enhanced CFTR-dependent chloride secretion in human sinus epithelium ex vivo to an extent comparable to the recently approved CFTR potentiator, ivacaftor. Using inside out patches from apical membranes of murine cells, resveratrol stimulated an ~8 picosiemens chloride channel consistent with CFTR. This observation was confirmed in HEK293 cells expressing exogenous CFTR. Treatment of sinonasal epithelium resulted in a significant increase in airway surface liquid depth (in µm: 8.08+/-1.68 vs. 6.11+/-0.47,control,p<0.05). There was no increase CFTR mRNA. CONCLUSION Resveratrol is a potent chloride secretagogue from the mucosal surface of sinonasal epithelium, and hydrates airway surface liquid by increasing CFTR channel open probability. The foundation for a clinical trial utilizing resveratrol as a therapeutic intervention to increase mucociliary transport and airway surface liquid hydration in sinus disease is strongly supported by these findings.
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Affiliation(s)
- Shaoyan Zhang
- Department of Surgery/Division of Otolaryngology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Angela C. Blount
- Department of Surgery/Division of Otolaryngology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Carmel M. McNicholas
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Daniel F. Skinner
- Department of Surgery/Division of Otolaryngology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Michael Chestnut
- Department of Surgery/Division of Otolaryngology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - John C. Kappes
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Eric J. Sorscher
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Bradford A. Woodworth
- Department of Surgery/Division of Otolaryngology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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Tobramycin Inhalation Powder: A Review of Its Use in the Treatment of Chronic Pseudomonas aeruginosa Infection in Patients with Cystic Fibrosis. Drugs 2013; 73:1815-27. [DOI: 10.1007/s40265-013-0141-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Zarogoulidis P, Kioumis I, Porpodis K, Spyratos D, Tsakiridis K, Huang H, Li Q, Turner JF, Browning R, Hohenforst-Schmidt W, Zarogoulidis K. Clinical experimentation with aerosol antibiotics: current and future methods of administration. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:1115-34. [PMID: 24115836 PMCID: PMC3793595 DOI: 10.2147/dddt.s51303] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Currently almost all antibiotics are administered by the intravenous route. Since several systems and situations require more efficient methods of administration, investigation and experimentation in drug design has produced local treatment modalities. Administration of antibiotics in aerosol form is one of the treatment methods of increasing interest. As the field of drug nanotechnology grows, new molecules have been produced and combined with aerosol production systems. In the current review, we discuss the efficiency of aerosol antibiotic studies along with aerosol production systems. The different parts of the aerosol antibiotic methodology are presented. Additionally, information regarding the drug molecules used is presented and future applications of this method are discussed.
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Affiliation(s)
- Paul Zarogoulidis
- Pulmonary Department, G Papanikolaou General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece ; Department of Interventional Pneumology, Ruhrlandklinik, West German Lung Center, University Hospital, University Duisburg-Essen, Essen, Germany
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Pharmacokinetic and tolerability profiles of tobramycin nebuliser solution 300 mg/4 ml administered by PARI eFlow(®) rapid and PARI LC Plus(®) nebulisers in cystic fibrosis patients. Pulm Pharmacol Ther 2012; 26:249-55. [PMID: 23232039 DOI: 10.1016/j.pupt.2012.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 11/30/2012] [Accepted: 12/02/2012] [Indexed: 11/21/2022]
Abstract
BACKGROUND Tobramycin nebuliser solution (TNS) is indicated for maintenance therapy in cystic fibrosis (CF) patients with chronic Pseudomonas aeruginosa (PA) infections. Adherence to recommended therapy in CF has always been a challenge and new generation nebulisers are increasingly used "off label" to reduce the time required for inhalation, potentially improving patient compliance. METHODS In this open-label, randomised, multi-centre, two-period crossover study, 27 CF patients with PA infection received TNS 300 mg/4 mL (TNS4) via the PARI eFlow(®) rapid or PARI LC Plus(®) nebuliser twice daily for 28 days in two study periods separated by a 4-week washout. The pharmacokinetic profile in plasma and sputum were determined after single and multiple dose administration on Day 1 and Day 28, respectively. Nebulisation times and general safety and tolerability profiles were evaluated throughout the study. RESULTS Plasma tobramycin pharmacokinetic profiles were similar for the eFlow and LC Plus nebulisers both on Day 1 and Day 28. After multiple dose administration for 28 days, the eFlow/LC Plus ratio of geometric means for plasma C(max) and AUC(0-t), were 85.32 (90% CI, 61.24-118.86) and 87.44 (90% CI, 64.87-117.87), respectively. Despite the high variability, sputum tobramycin C(max) and AUC(0-t) for the eFlow on Day 28 tended to be higher than for the LC Plus (90% CI for the ratio, 86.11-226.45 and 81.81-236.71), respectively. Nebulisation times were significantly shorter for the eFlow with a median time for nebulisation of 5 min in comparison to 13 min for the LC Plus. Safety data confirmed a favourable safety profile for TNS4, with the majority of the findings being related to the underlying CF disease. CONCLUSIONS Plasma and sputum pharmacokinetic data in CF patients with chronic PA infection support comparable pulmonary delivery and safety of TNS4 administered using different nebulisers, with a significantly shorter nebulisation time for the eFlow.
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