1
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Bonfield TL, Zuckerman ST, Sutton MT, Korley JN, von Recum HA. Polymerized cyclodextrin microparticles for sustained antibiotic delivery in lung infections. J Biomed Mater Res A 2024; 112:1305-1316. [PMID: 38380736 PMCID: PMC11187681 DOI: 10.1002/jbm.a.37680] [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: 07/07/2023] [Revised: 01/12/2024] [Accepted: 01/19/2024] [Indexed: 02/22/2024]
Abstract
Pulmonary infections complicate chronic lung diseases requiring attention to both the pathophysiology and complexity associated with infection management. Patients with cystic fibrosis (CF) struggle with continuous bouts of pulmonary infections, contributing to lung destruction and eventual mortality. Additionally, CF patients struggle with airways that are highly viscous, with accumulated mucus creating optimal environments for bacteria colonization. The unique physiology and altered airway environment provide an ideal niche for bacteria to change their phenotype often becoming resistant to current treatments. Colonization with multiple pathogens at the same time further complicate treatment algorithms, requiring drug combinations that can challenge CF patient tolerance to treatment. The goal of this research initiative was to explore the utilization of a microparticle antibiotic delivery system, which could provide localized and sustained antibiotic dosing. The outcome of this work demonstrates the feasibility of providing efficient localized delivery of antibiotics to manage infection using both preclinical in vitro and in vivo CF infection models. The studies outlined in this manuscript demonstrate the proof-of-concept and unique capacity of polymerized cyclodextrin microparticles to provide site-directed management of pulmonary infections.
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Affiliation(s)
- Tracey L. Bonfield
- Department of Genetics and Genome Sciences, Case Western Reserve University
| | - Sean T. Zuckerman
- Affinity Therapeutics, Cleveland Ohio, United States
- Department of Biomedical Engineering, Case Western Reserve University
| | - Morgan T. Sutton
- Department of Genetics and Genome Sciences, Case Western Reserve University
- Saint Jude Children Research Hospital Graduate School of Biomedical Sciences, Memphis Tennessee
| | | | - Horst A. von Recum
- Affinity Therapeutics, Cleveland Ohio, United States
- Department of Biomedical Engineering, Case Western Reserve University
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2
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Wells M, Mikesh M, Gordon V. Structure-preserving fixation allows scanning electron microscopy to reveal biofilm microstructure and interactions with immune cells. J Microsc 2024; 293:59-68. [PMID: 38098170 PMCID: PMC10764082 DOI: 10.1111/jmi.13252] [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: 08/31/2023] [Revised: 11/27/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
Pseudomonas aeruginosa is a pathogen that forms robust biofilms which are commonly associated with chronic infections and cannot be successfully cleared by the immune system. Neutrophils, the most common white blood cells, target infections with pathogen-killing mechanisms that are rendered largely ineffective by the protective physicochemical structure of a biofilm. Visualisation of the complex interactions between immune cells and biofilms will advance understanding of how biofilms evade the immune system and could aid in developing treatment methods that promote immune clearance with minimal harm to the host. Scanning electron microscopy (SEM) distinguishes itself as a powerful, high-resolution tool for obtaining strikingly clear and detailed topographical images. However, taking full advantage of SEM's potential for high-resolution imaging requires that the fixation process simultaneously preserve both intricate biofilm architecture and the morphologies and structural signatures characterising neutrophils responses at an infection site. Standard aldehyde-based fixation techniques result in significant loss of biofilm matrix material and morphologies of responding immune cells, thereby obscuring the details of immune interactions with the biofilm matrix. Here we show an improved fixation technique using the cationic dye alcian blue to preserve and visualise neutrophil interactions with the three-dimensional architecture of P. aeruginosa biofilms. We also demonstrate that this technique better preserves structures of biofilms grown from two other bacterial species, Klebsiella pneumoniae and Burkholderia thailandensis.
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Affiliation(s)
- Marilyn Wells
- Department of Physics, The University of Texas at Austin, Austin, Texas, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, Texas, USA
| | - Michelle Mikesh
- Center for Biomedical Research Support, The University of Texas at Austin, Austin, Texas, USA
| | - Vernita Gordon
- Department of Physics, The University of Texas at Austin, Austin, Texas, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, Texas, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Austin, Texas, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, Texas, USA
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3
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Wells MJ, Currie H, Gordon VD. Physiological Concentrations of Calcium Interact with Alginate and Extracellular DNA in the Matrices of Pseudomonas aeruginosa Biofilms to Impede Phagocytosis by Neutrophils. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17050-17058. [PMID: 37972353 PMCID: PMC10764079 DOI: 10.1021/acs.langmuir.3c01637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Biofilms are communities of interacting microbes embedded in a matrix of polymer, protein, and other materials. Biofilms develop distinct mechanical characteristics that depend on their predominant matrix components. These matrix components may be produced by microbes themselves or, for infections in vivo, incorporated from the host environment. Pseudomonas aeruginosa (P. aeruginosa) is a human pathogen that forms robust biofilms that extensively tolerate antibiotics and effectively evade clearance by the immune system. Two of the important bacterial-produced polymers in the matrices of P. aeruginosa biofilms are alginate and extracellular DNA (eDNA), both of which are anionic and therefore have the potential to interact electrostatically with cations. Many physiological sites of infection contain significant concentrations of the calcium ion (Ca2+). In this study, we investigate the structural and mechanical impacts of Ca2+ supplementation in alginate-dominated biofilms grown in vitro, and we evaluate the impact of targeted enzyme treatments on clearance by immune cells. We use multiple-particle tracking microrheology to evaluate the changes in biofilm viscoelasticity caused by treatment with alginate lyase or DNase I. For biofilms grown without Ca2+, we correlate a decrease in relative elasticity with increased phagocytic success. However, we find that growth with Ca2+ supplementation disrupts this correlation except in the case where both enzymes are applied. This suggests that the calcium cation may be impacting the microstructure of the biofilm in nontrivial ways. Indeed, confocal laser scanning fluorescence microscopy and scanning electron microscopy reveal unique Ca2+-dependent eDNA and alginate microstructures. Our results suggest that the presence of Ca2+ drives the formation of structurally and compositionally discrete microdomains within the biofilm through electrostatic interactions with the anionic matrix components eDNA and alginate. Further, we observe that these structures serve a protective function as the dissolution of both components is required to render biofilm bacteria vulnerable to phagocytosis by neutrophils.
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Affiliation(s)
- Marilyn J. Wells
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Hailey Currie
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Vernita D. Gordon
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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4
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Dolan JP, Ahmadipour S, Wahart AJC, Cheallaigh AN, Sari S, Eurtivong C, Lima MA, Skidmore MA, Volcho KP, Reynisson J, Field RA, Miller GJ. Virtual screening, identification and in vitro validation of small molecule GDP-mannose dehydrogenase inhibitors. RSC Chem Biol 2023; 4:865-870. [PMID: 37920392 PMCID: PMC10619135 DOI: 10.1039/d3cb00126a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 08/26/2023] [Indexed: 11/04/2023] Open
Abstract
Upon undergoing mucoid conversion within the lungs of cystic fibrosis patients, the pathogenic bacterium Pseudomonas aeruginosa synthesises copious quantities of the virulence factor and exopolysaccharide alginate. The enzyme guanosine diphosphate mannose dehydrogenase (GMD) catalyses the rate-limiting step and irreversible formation of the alginate sugar nucleotide building block, guanosine diphosphate mannuronic acid. Since there is no corresponding enzyme in humans, strategies that could prevent its mechanism of action could open a pathway for new and selective inhibitors to disrupt bacterial alginate production. Using virtual screening, a library of 1447 compounds within the Known Drug Space parameters were evaluated against the GMD active site using the Glide, FRED and GOLD algorithms. Compound hit evaluation with recombinant GMD refined the panel of 40 potential hits to 6 compounds which reduced NADH production in a time-dependent manner; of which, an usnic acid derivative demonstrated inhibition six-fold stronger than a previously established sugar nucleotide inhibitor, with an IC50 value of 17 μM. Further analysis by covalent docking and mass spectrometry confirm a single site of GMD alkylation.
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Affiliation(s)
- Jonathan P Dolan
- Lennard-Jones Laboratory, School of Chemical & Physical Sciences, Keele University Keele Staffordshire ST5 5BG UK
- Centre for Glycoscience, Keele University Keele Staffordshire ST5 5BG UK
| | - Sanaz Ahmadipour
- Department of Chemistry & Manchester Institute of Biotechnology, The University of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Alice J C Wahart
- Lennard-Jones Laboratory, School of Chemical & Physical Sciences, Keele University Keele Staffordshire ST5 5BG UK
- Centre for Glycoscience, Keele University Keele Staffordshire ST5 5BG UK
| | - Aisling Ní Cheallaigh
- Lennard-Jones Laboratory, School of Chemical & Physical Sciences, Keele University Keele Staffordshire ST5 5BG UK
- Centre for Glycoscience, Keele University Keele Staffordshire ST5 5BG UK
| | - Suat Sari
- Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Chemistry 06100 Ankara Turkey
| | - Chatchakorn Eurtivong
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University 447 Si Ayutthaya Road Ratchathewi Bangkok 10400 Thailand
| | - Marcelo A Lima
- Centre for Glycoscience, Keele University Keele Staffordshire ST5 5BG UK
- School of Life Sciences, Keele University Keele Staffordshire ST5 5BG UK
| | - Mark A Skidmore
- Centre for Glycoscience, Keele University Keele Staffordshire ST5 5BG UK
- School of Life Sciences, Keele University Keele Staffordshire ST5 5BG UK
| | - Konstantin P Volcho
- N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences 630090 Novosibirsk Russia
| | - Jóhannes Reynisson
- Centre for Glycoscience, Keele University Keele Staffordshire ST5 5BG UK
- Hornbeam Building, School of Pharmacy & Bioengineering, Keele University Keele Staffordshire ST5 5BG UK
| | - Robert A Field
- Department of Chemistry & Manchester Institute of Biotechnology, The University of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Gavin J Miller
- Lennard-Jones Laboratory, School of Chemical & Physical Sciences, Keele University Keele Staffordshire ST5 5BG UK
- Centre for Glycoscience, Keele University Keele Staffordshire ST5 5BG UK
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5
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Wells MJ, Currie H, Gordon VD. Physiological concentrations of calcium interact with alginate and extracellular DNA in the matrices of Pseudomonas aeruginosa biofilms to impede phagocytosis by neutrophils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563605. [PMID: 37961083 PMCID: PMC10634743 DOI: 10.1101/2023.10.23.563605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Biofilms are communities of interacting microbes embedded in a matrix of polymer, protein, and other materials. Biofilms develop distinct mechanical characteristics that depend on their predominant matrix components. These matrix components may be produced by microbes themselves or, for infections in vivo, incorporated from the host environment. Pseudomonas aeruginosa is a human pathogen that forms robust biofilms that extensively tolerate antibiotics and effectively evade clearance by the immune system. Two of the important bacterial-produced polymers in the matrices of P. aeruginosa biofilms are alginate and extracellular DNA (eDNA), both of which are anionic and therefore have the potential to interact electrostatically with cations. Many physiological sites of infection contain significant concentrations of the calcium ion (Ca2+). In this study we investigate the structural and mechanical impacts of Ca2+ supplementation in alginate-dominated biofilms grown in vitro and we evaluate the impact of targeted enzyme treatments on clearance by immune cells. We use multiple particle tracking microrheology to evaluate the changes in biofilm viscoelasticity caused by treatment with alginate lyase and/or DNAse I. For biofilms grown without Ca2+, we correlate a decrease in relative elasticity with increased phagocytic success. However, we find that growth with Ca2+ supplementation disrupts this correlation except in the case where both enzymes are applied. This suggests that the calcium cation may be impacting the microstructure of the biofilm in non-trivial ways. Indeed, confocal laser scanning fluorescence microscopy and scanning electron microscopy reveal unique Ca2+-dependent eDNA and alginate microstructures. Our results suggest that the presence of Ca2+ drives the formation of structurally and compositionally discrete microdomains within the biofilm through electrostatic interactions with the anionic matrix components eDNA and alginate. Further, we observe that these structures serve a protective function as the dissolution of both components is required to render biofilm bacteria vulnerable to phagocytosis by neutrophils.
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Affiliation(s)
- Marilyn J. Wells
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Hailey Currie
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Vernita D. Gordon
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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6
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Kausar A. Carbohydrate polymer derived nanocomposites: design, features and potential for biomedical applications. POLYM-PLAST TECH MAT 2023. [DOI: 10.1080/25740881.2022.2121221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Affiliation(s)
- Ayesha Kausar
- National Center for Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan
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Balducci E, Papi F, Capialbi DE, Del Bino L. Polysaccharides' Structures and Functions in Biofilm Architecture of Antimicrobial-Resistant (AMR) Pathogens. Int J Mol Sci 2023; 24:ijms24044030. [PMID: 36835442 PMCID: PMC9965654 DOI: 10.3390/ijms24044030] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023] Open
Abstract
Bacteria and fungi have developed resistance to the existing therapies such as antibiotics and antifungal drugs, and multiple mechanisms are mediating this resistance. Among these, the formation of an extracellular matrix embedding different bacterial cells, called biofilm, is an effective strategy through which bacterial and fungal cells are establishing a relationship in a unique environment. The biofilm provides them the possibility to transfer genes conferring resistance, to prevent them from desiccation and to impede the penetration of antibiotics or antifungal drugs. Biofilms are formed of several constituents including extracellular DNA, proteins and polysaccharides. Depending on the bacteria, different polysaccharides form the biofilm matrix in different microorganisms, some of them involved in the first stage of cells' attachment to surfaces and to each other, and some responsible for giving the biofilm structure resistance and stability. In this review, we describe the structure and the role of different polysaccharides in bacterial and fungal biofilms, we revise the analytical methods to characterize them quantitatively and qualitatively and finally we provide an overview of potential new antimicrobial therapies able to inhibit biofilm formation by targeting exopolysaccharides.
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Affiliation(s)
| | | | - Daniela Eloisa Capialbi
- GSK, 53100 Siena, Italy
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy
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Qian H, Ye Z, Pi L, Ao J. Roles and current applications of S-nitrosoglutathione in anti-infective biomaterials. Mater Today Bio 2022; 16:100419. [PMID: 36105674 PMCID: PMC9465324 DOI: 10.1016/j.mtbio.2022.100419] [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] [Received: 07/12/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022]
Abstract
Bacterial infections can compromise the physical and biological functionalities of humans and pose a huge economical and psychological burden on infected patients. Nitric oxide (NO) is a broad-spectrum antimicrobial agent, whose mechanism of action is not affected by bacterial resistance. S-nitrosoglutathione (GSNO), an endogenous donor and carrier of NO, has gained increasing attention because of its potent antibacterial activity and efficient biocompatibility. Significant breakthroughs have been made in the application of GSNO in biomaterials. This review is based on the existing evidence that comprehensively summarizes the progress of antimicrobial GSNO applications focusing on their anti-infective performance, underlying antibacterial mechanisms, and application in anti-infective biomaterials. We provide an accurate overview of the roles and applications of GSNO in antibacterial biomaterials and shed new light on the avenues for future studies.
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Key Words
- A.baumannii, Acinetobacter baumannii
- AgNPs, Silver nanoparticles
- Antibacterial property
- BMSCs, Bone marrow stem cells
- Bacterial resistance
- Biomaterials
- C.albicans, Candida albicans
- CS/GE, Chitosan/gelatin
- Cu, copper
- DMSO, Dimethyl sulfoxide
- DPA, Diethylenetriamine pentaacetic acid
- E. coli, Escherichia coli
- E.tenella, Eimeria tenella
- ECC, Extracorporeal circulation
- ECM, Experimental cerebral malaria
- GSNO, S-Nitrosoglutathione
- GSNOR, S-Nitrosoglutathione Reductase
- H.pylori, Helicobacter pylori
- HCC, Human cervical carcinoma
- HDFs, Human dermal fibroblasts
- HUVEC, Human umbilical vein endothelial cells
- ICR, Imprinted control region
- Infection
- K.Pneumonia, Klebsiella Pneumonia
- L.amazonensis, Leishmania amazonensis
- L.major, Leishmania major
- M.Tuberculosis, Mycobacterium tuberculosis
- M.smegmatis, Mycobacterium smegmatis
- MOF, Metal–organic framework
- MRPA, Multidrug-resistant Pseudomonas aeruginosa
- MRSA, Methicillin resistant Staphylococcus aureus
- N. gonorrhoeae, Neisseria gonorrhoeae
- N.meningitidis, Neisseria meningitidis
- NA, Not available
- NO-np, NO-releasing nanoparticulate platform
- NP, Nanoparticle
- P.aeruginosa, Pseudomonas aeruginosa
- P.berghei, Plasmodium berghei
- P.mirabilis, Proteus mirabilis
- PCL, Polycaprolactone
- PCVAD, Porcine circovirus-associated disease
- PDA-GSNO NPs, Polydopamine nanoparticles containing GSNO
- PDAM@Cu, polydopamine based copper coatings
- PEG, polyethylene glycol
- PHB, polyhydroxybutyrate
- PLA, polylactic acid
- PLGA, poly(lactic-co-glycolic acid)
- PTT, Photothermal therapy
- PVA, poly(vinyl alcohol)
- PVA/PEG, poly(vinyl alcohol)/poly(ethylene glycol)
- PVC, poly(vinyl chloride)
- S-nitrosoglutathione
- S. typhimurium, Salmonella typhimurium
- S.aureus, Staphylococcus aureus
- S.epidermidis, Staphylococcus epidermidis
- S.pneumoniae, Streptococcus pneumoniae
- SAKI, Septic acute kidney injury
- SCI, Spinal cord slices
- Se, Selenium
- Sp3, Specificity proteins 3
- TDC, Tunneled dialysis catheters
- TMOS, Tetramethylorthosilicate
- ZnO, Zinc oxide
- cftr, cystic fibrosis transmembrane conductance regulatory gene
- d, day
- h, hour
- min, minute
- pSiNPs, porous silicon nanoparticles
- w, week
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Affiliation(s)
- Hu Qian
- Department of Orthopaedic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Zhimin Ye
- Department of Pathology, School of Basic Medical Sciences, Central South University, Changsha, China
| | - Lanping Pi
- Nursing Department, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Jun Ao
- Department of Orthopaedic Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, China
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Jackson SA, Duan M, Zhang P, Ihua MW, Stengel DB, Duan D, Dobson ADW. Isolation, identification, and biochemical characterization of a novel bifunctional phosphomannomutase/phosphoglucomutase from the metagenome of the brown alga Laminaria digitata. Front Microbiol 2022; 13:1000634. [PMID: 36212884 PMCID: PMC9537760 DOI: 10.3389/fmicb.2022.1000634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022] Open
Abstract
Macroalgae host diverse epiphytic bacterial communities with potential symbiotic roles including important roles influencing morphogenesis and growth of the host, nutrient exchange, and protection of the host from pathogens. Macroalgal cell wall structures, exudates, and intra-cellular environments possess numerous complex and valuable carbohydrates such as cellulose, hemi-cellulose, mannans, alginates, fucoidans, and laminarin. Bacterial colonizers of macroalgae are important carbon cyclers, acquiring nutrition from living macroalgae and also from decaying macroalgae. Seaweed epiphytic communities are a rich source of diverse carbohydrate-active enzymes which may have useful applications in industrial bioprocessing. With this in mind, we constructed a large insert fosmid clone library from the metagenome of Laminaria digitata (Ochrophyta) in which decay was induced. Subsequent sequencing of a fosmid clone insert revealed the presence of a gene encoding a bifunctional phosphomannomutase/phosphoglucomutase (PMM/PGM) enzyme 10L6AlgC, closely related to a protein from the halophilic marine bacterium, Cobetia sp. 10L6AlgC was subsequently heterologously expressed in Escherichia coli and biochemically characterized. The enzyme was found to possess both PMM and PGM activity, which had temperature and pH optima of 45°C and 8.0, respectively; for both activities. The PMM activity had a Km of 2.229 mM and Vmax of 29.35 mM min−1 mg−1, while the PGM activity had a Km of 0.5314 mM and a Vmax of 644.7 mM min−1 mg−1. Overall characterization of the enzyme including the above parameters as well as the influence of various divalent cations on these activities revealed that 10L6AlgC has a unique biochemical profile when compared to previously characterized PMM/PGM bifunctional enzymes. Thus 10L6AlgC may find utility in enzyme-based production of biochemicals with different potential industrial applications, in which other bacterial PMM/PGMs have previously been used such as in the production of low-calorie sweeteners in the food industry.
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Affiliation(s)
- Stephen A. Jackson
- School of Microbiology, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
| | - Maohang Duan
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Pengyan Zhang
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Maureen W. Ihua
- School of Microbiology, University College Cork, Cork, Ireland
| | - Dagmar B. Stengel
- Botany and Plant Science, School of Natural Sciences, Ryan Institute for Environmental, Marine and Energy Research, University of Galway, Galway, Ireland
| | - Delin Duan
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- *Correspondence: Delin Duan,
| | - Alan D. W. Dobson
- School of Microbiology, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
- Alan D. W. Dobson,
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In Vitro Synergistic Inhibitory Activity of Natural Alkaloid Berberine Combined with Azithromycin against Alginate Production by Pseudomonas aeruginosa PAO1. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:3858500. [PMID: 36124086 PMCID: PMC9482538 DOI: 10.1155/2022/3858500] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/11/2022] [Accepted: 08/29/2022] [Indexed: 11/18/2022]
Abstract
Background. Berberine (BER) is a natural isoquinoline alkaloid which extensively been applied to treat bacterial infection in TCM for a long time. Alginate is an important component of Pseudomonas aeruginosa biofilm. Herein, we investigated the effects of berberine and azithromycin (AZM) on alginate in the biofilm of P. aeruginosa PAO1. Methods. The MIC and synergistic activity of BER and AZM against PAO1 were determined using the micro broth dilution and checkerboard titration methods, respectively. The effect of BER on PAO1 growth was evaluated using a time-kill assay. Moreover, the effects of BER, AZM, and a combination of both on PAO1 biofilm formation, kinesis, and virulence factor expression were evaluated at subinhibitory concentrations. The alginate content in the biofilm was detected using ELISA, and the relative expression of alginate formation-related genes algD, algR, and algG was detected by qRT-PCR. Results. Simultaneous administration of berberine significantly reduced the MIC of azithromycin, and berberine at a certain concentration inhibited PAO1 growth. Moreover, combined berberine and azithromycin had synergistic effects against PAO1, significantly reducing biofilm formation, swarming, and twitching motility, and the production of virulence factors. The relative expression of alginate-related regulatory genes algG, algD, and algR of the combined treatment group was significantly lower than that of the control group. Conclusion. In summary, berberine and azithromycin in combination had a significant synergistic effect on the inhibition of alginate production by P. aeruginosa. Further molecular studies are in great need to reveal the mechanisms underlying the synergistic activity between berberine and azithromycin.
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11
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Planet PJ. Adaptation and Evolution of Pathogens in the Cystic Fibrosis Lung. J Pediatric Infect Dis Soc 2022; 11:S23-S31. [PMID: 36069898 PMCID: PMC9451014 DOI: 10.1093/jpids/piac073] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/11/2022] [Indexed: 02/05/2023]
Abstract
As opposed to acute respiratory infections, the persistent bacterial infections of the lung that characterize cystic fibrosis (CF) provide ample time for bacteria to evolve and adapt. The process of adaptation is recorded in mutations that accumulate over time in the genomes of the infecting bacteria. Some of these mutations lead to obvious phenotypic differences such as antibiotic resistance or the well-known mucoid phenotype of Pseudomonas aeruginosa. Other mutations may be just as important but harder to detect such as increased mutation rates, cell surface changes, and shifts in metabolism and nutrient acquisition. Remarkably, many of the adaptations occur again and again in different patients, signaling that bacteria are adapting to solve specific challenges in the CF respiratory tract. This parallel evolution even extends across distinct bacterial species. This review addresses the bacterial systems that are known to change in long-term CF infections with a special emphasis on cross-species comparisons. Consideration is given to how adaptation may impact health in CF, and the possible evolutionary mechanisms that lead to the repeated parallel adaptations.
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Affiliation(s)
- Paul J Planet
- Corresponding Author: Paul J. Planet, MD, PhD, 3615 Civic Center Blvd, Philadelphia, PA 19104. E-mail:
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12
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Nitric oxide inhibits alginate biosynthesis in Pseudomonas aeruginosa and increases its sensitivity to tobramycin by downregulating algU gene expression. Nitric Oxide 2022; 128:50-58. [PMID: 35987450 DOI: 10.1016/j.niox.2022.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 11/23/2022]
Abstract
In the process of chronic cystic fibrosis (CF) infection, Pseudomonas aeruginosa (PA) is converted into a mucoid phenotype characterized by an overproduction of exopolysaccharide alginate. The alginate forms a thick mucus that causes difficulty in patient's breathing, drug resistance and contributes to both the morbidity and mortality of the patient. AlgU of PA, an extracytoplasmic function sigma factor, is responsible for the alginate overproduction and leads to mucoidy and chronic infection of CF patients. In this report, we found that endogenous and exogenous nitric oxide (NO) can significantly reduce algU expression, leading to down-regulation of a series of alginate synthesis-related genes (algD, alg8, algX, and algK), eventually down-regulated alginate synthesis. A fluorescent reporter strain was constructed to clarify the inhibitory effect of alginate synthesis through real-time monitoring in different conditions. The results showed that NO presented inhibitory effect on alginate synthesis in nine clinical PA isolates as in the PA reference strain, and the reduction of alginate was more significant in three mucoid strains (by about 51%, 70% and 61%, respectively, while 47% for the reference strain). In the co-culture system, effect of NO on PA fluorescence intensity is similar to that in monocultures, with the best effect at 10 μM NO donor sodium nitroprusside (SNP). Finally, we examined the changes in the antibiotic susceptibility of PA under NO-inhibited alginate conditions. In the presence of 10 μM SNP, the number of planktonic cells increased, and both adherent and planktonic PA cells showed increased susceptibility to tobramycin. We thus suggest that NO can potentially be employed as a therapeutic strategy to prevent cystic fibrosis lungs from PA infection.
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13
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Preclinical Evaluation of Recombinant Microbial Glycoside Hydrolases as Antibiofilm Agents in Acute Pulmonary Pseudomonas aeruginosa Infection. Antimicrob Agents Chemother 2022; 66:e0005222. [PMID: 35862738 PMCID: PMC9380554 DOI: 10.1128/aac.00052-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The bacterium Pseudomonas aeruginosa can colonize the airways of patients with chronic lung disease. Within the lung, P. aeruginosa forms biofilms that can enhance resistance to antibiotics and immune defenses. P. aeruginosa biofilm formation is dependent on the secretion of matrix exopolysaccharides, including Pel and Psl. In this study, recombinant glycoside hydrolases (GHs) that degrade Pel and Psl were evaluated alone and in combination with antibiotics in a mouse model of P. aeruginosa infection. Intratracheal GH administration was well tolerated by mice. Pharmacokinetic analysis revealed that, although GHs have short half-lives, administration of two GHs in combination resulted in increased GH persistence. Combining GH prophylaxis and treatment with the antibiotic ciprofloxacin resulted in greater reduction in pulmonary bacterial burden than that with either agent alone. This study lays the foundation for further exploration of GH therapy in bacterial infections.
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14
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Le Mauff F, Razvi E, Reichhardt C, Sivarajah P, Parsek MR, Howell PL, Sheppard DC. The Pel polysaccharide is predominantly composed of a dimeric repeat of α-1,4 linked galactosamine and N-acetylgalactosamine. Commun Biol 2022; 5:502. [PMID: 35618750 PMCID: PMC9135694 DOI: 10.1038/s42003-022-03453-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 05/06/2022] [Indexed: 12/20/2022] Open
Abstract
The genetic capacity to synthesize the biofilm matrix exopolysaccharide Pel is widespread among Gram-negative and Gram-positive bacteria. However, its exact chemical structure has been challenging to determine. Using a Pseudomonas aeruginosa strain engineered to overproduce Pel, improvements to the isolation procedure, and selective hydrolysis with the glycoside hydrolase PelAh, we demonstrate that Pel is a partially de-N-acetylated linear polymer of α-1,4-N-acetylgalactosamine comprised predominantly of dimeric repeats of galactosamine and N-acetylgalactosamine. The structure of the Pel exopolysaccharide from Pseudomonas aeruginosa is fully characterized.
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Affiliation(s)
- François Le Mauff
- Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montreal, QC, Canada.,Infectious Disease in Global Health Program, McGill University Health Centre, Montreal, QC, Canada.,McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, QC, Canada
| | - Erum Razvi
- Program in Molecular Medicine, Research Institute The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Courtney Reichhardt
- Department of Microbiology, University of Washington, Seattle, WA, USA.,Department of Chemistry, Washington University, St. Louis, MO, 63130, USA
| | - Piyanka Sivarajah
- Program in Molecular Medicine, Research Institute The Hospital for Sick Children, Toronto, ON, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - P Lynne Howell
- Program in Molecular Medicine, Research Institute The Hospital for Sick Children, Toronto, ON, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
| | - Donald C Sheppard
- Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montreal, QC, Canada. .,Infectious Disease in Global Health Program, McGill University Health Centre, Montreal, QC, Canada. .,McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, QC, Canada.
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15
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Biofilm Survival Strategies in Chronic Wounds. Microorganisms 2022; 10:microorganisms10040775. [PMID: 35456825 PMCID: PMC9025119 DOI: 10.3390/microorganisms10040775] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 01/22/2023] Open
Abstract
Bacterial biofilms residing in chronic wounds are thought to have numerous survival strategies, making them extremely difficult to eradicate and resulting in long-term infections. However, much of our knowledge regarding biofilm persistence stems from in vitro models and experiments performed in vivo in animal models. While the knowledge obtained from such experiments is highly valuable, its direct translation to the human clinical setting should be undertaken with caution. In this review, we highlight knowledge obtained from human clinical samples in different aspects of biofilm survival strategies. These strategies have been divided into segments of the following attributes: altered transcriptomic profiles, spatial distribution, the production of extracellular polymeric substances, an altered microenvironment, inter-and intra-species interactions, and heterogeneity in the bacterial population. While all these attributes are speculated to contribute to the enhanced persistence of biofilms in chronic wounds, only some of them have been demonstrated to exist in human wounds. Some of the attributes have been observed in other clinical diseases while others have only been observed in vitro. Here, we have strived to clarify the limitations of the current knowledge in regard to this specific topic, without ignoring important in vitro and in vivo observations.
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16
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Secor PR, Michaels LA, Bublitz DC, Jennings LK, Singh PK. The Depletion Mechanism Actuates Bacterial Aggregation by Exopolysaccharides and Determines Species Distribution & Composition in Bacterial Aggregates. Front Cell Infect Microbiol 2022; 12:869736. [PMID: 35782109 PMCID: PMC9243289 DOI: 10.3389/fcimb.2022.869736] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteria in natural environments and infections are often found in cell aggregates suspended in polymer-rich solutions, and aggregation can promote bacterial survival and stress resistance. One aggregation mechanism, called depletion aggregation, is driven by physical forces between bacteria and high concentrations of polymers in the environment rather than bacterial activity per se. As such, bacteria aggregated by the depletion mechanism will disperse when polymer concentrations fall unless other adhesion mechanisms supervene. Here we investigated whether the depletion mechanism can actuate the aggregating effects of Pseudomonas aeruginosa exopolysaccharides for suspended (i.e. not surface attached) bacteria, and how depletion affects bacterial inter-species interactions. We found that cells overexpressing the exopolysaccharides Pel and Psl remained aggregated after short periods of depletion aggregation whereas wild-type and mucoid P. aeruginosa did not. In co-culture, depletion aggregation had contrasting effects on P. aeruginosa's interactions with coccus- and rod-shaped bacteria. Depletion caused S. aureus (cocci) and P. aeruginosa (rods) to segregate from each other and S. aureus to resist secreted P. aeruginosa antimicrobial factors resulting in species co-existence. In contrast, depletion aggregation caused P. aeruginosa and Burkholderia sp. (both rods) to intermix, enhancing type VI secretion inhibition of Burkholderia by P. aeruginosa, leading to P. aeruginosa dominance. These results show that in addition to being a primary cause of aggregation in polymer-rich suspensions, physical forces inherent to the depletion mechanism can promote aggregation by some self-produced exopolysaccharides and determine species distribution and composition of bacterial communities.
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Affiliation(s)
- Patrick R Secor
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Lia A Michaels
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - DeAnna C Bublitz
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Laura K Jennings
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Pradeep K Singh
- Department of Microbiology, University of Washington, Seattle, WA, United States
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17
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Rahman MU, Fleming DF, Sinha I, Rumbaugh KP, Gordon VD, Christopher GF. Effect of collagen and EPS components on the viscoelasticity of Pseudomonas aeruginosa biofilms. SOFT MATTER 2021; 17:6225-6237. [PMID: 34109345 PMCID: PMC8283923 DOI: 10.1039/d1sm00463h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes thousands of deaths every year in part due to its ability to form biofilms composed of bacteria embedded in a matrix of self-secreted extracellular polysaccharides (EPS), e-DNA, and proteins. In chronic wounds, biofilms are exposed to the host extracellular matrix, of which collagen is a major component. How bacterial EPS interacts with host collagen and whether this interaction affects biofilm viscoelasticity is not well understood. Since physical disruption of biofilms is often used in their removal, knowledge of collagen's effects on biofilm viscoelasticity may enable new treatment strategies that are better tuned to biofilms growing in host environments. In this work, biofilms are grown in the presence of different concentrations of collagen that mimic in vivo conditions. In order to explore collagen's interaction with EPS, nine strains of P. aeruginosa with different patterns of EPS production were used to grow biofilms. Particle tracking microrheology was used to characterize the mechanical development of biofilms over two days. Collagen is found to decrease biofilm compliance and increase relative elasticity regardless of the EPS present in the system. However, this effect is minimized when biofilms overproduce EPS. Collagen appears to become a de facto component of the EPS, through binding to bacteria or physical entanglement.
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Affiliation(s)
- Minhaz Ur Rahman
- Department of Mechanical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, TX, USA.
| | - Derek F Fleming
- Department of Surgery, Texas Tech Health Sciences, Lubbock, TX, USA
| | - Indranil Sinha
- Department of Mechanical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, TX, USA.
| | | | - Vernita D Gordon
- Department of Physics, Center for Nonlinear Dynamics, Interdisciplinary Life Sciences Graduate Programs, LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, TX, USA
| | - Gordon F Christopher
- Department of Mechanical Engineering, Whitacre College of Engineering, Texas Tech University, Lubbock, TX, USA.
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18
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Moser C, Jensen PØ, Thomsen K, Kolpen M, Rybtke M, Lauland AS, Trøstrup H, Tolker-Nielsen T. Immune Responses to Pseudomonas aeruginosa Biofilm Infections. Front Immunol 2021; 12:625597. [PMID: 33692800 PMCID: PMC7937708 DOI: 10.3389/fimmu.2021.625597] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/20/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a key pathogen of chronic infections in the lungs of cystic fibrosis patients and in patients suffering from chronic wounds of diverse etiology. In these infections the bacteria congregate in biofilms and cannot be eradicated by standard antibiotic treatment or host immune responses. The persistent biofilms induce a hyper inflammatory state that results in collateral damage of the adjacent host tissue. The host fails to eradicate the biofilm infection, resulting in hindered remodeling and healing. In the present review we describe our current understanding of innate and adaptive immune responses elicited by P. aeruginosa biofilms in cystic fibrosis lung infections and chronic wounds. This includes the mechanisms that are involved in the activation of the immune responses, as well as the effector functions, the antimicrobial components and the associated tissue destruction. The mechanisms by which the biofilms evade immune responses, and potential treatment targets of the immune response are also discussed.
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Affiliation(s)
- Claus Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kim Thomsen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Morten Rybtke
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Sofie Lauland
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Hannah Trøstrup
- Department of Plastic Surgery and Breast Surgery, Zealand University Hospital, Roskilde, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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19
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Material properties of interfacial films of mucoid and nonmucoid Pseudomonas aeruginosa isolates. Acta Biomater 2020; 118:129-140. [PMID: 33053427 DOI: 10.1016/j.actbio.2020.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 09/20/2020] [Accepted: 10/07/2020] [Indexed: 12/19/2022]
Abstract
Chronic lung infection with bacterial biofilms is a leading cause of death in cystic fibrosis (CF) patients. Pseudomonas aeruginosa, one of the many species colonizing the lung airways, can undergo pathoadaptation, leading to a mucoid phenotype with interesting material properties. We hypothesize that the surface properties and extracellular materials of mucoid P. aeruginosa cells greatly influence the mechanical behavior of their films at fluid interfaces. In this study, we investigate the interfacial properties of films formed by nonmucoid (PANT) and mucoid (PASL) strains of P. aeruginosa isolated from CF patients. We use pendant drop elastometry to analyze the interfacial response of the films formed by PANT and PASL at the hexadecane-water interface. The dynamic rheological analyses of the films highlight the distinctive signature of the mucoid strains at fluid interfaces. The mucoid films exhibit greater relaxation following a compressive strain than a tensile one, while a full hysteresis response is achieved by the nonmucoid films; this indicates that the material properties of the PANT films are conserved under both compression and tension. The wrinkling and shape analyses of the interfacial bacterial films elucidate that the mucoid strain exhibits remarkable viscoelastic properties, enabling the remodeling of the living films and dissipation of the compressive stress. The comparative analysis of the material properties of mucoid and nonmucoid P. aeruginosa cells indicates that mucoid switch can play an important role in protecting the bacteria from interfacial stresses. Further characterization of interfacial bacterial films will provide new insights into the development of methods for controlling interfacial films of bacteria.
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20
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Chan SY, Liu SY, Seng Z, Chua SL. Biofilm matrix disrupts nematode motility and predatory behavior. ISME JOURNAL 2020; 15:260-269. [PMID: 32958848 DOI: 10.1038/s41396-020-00779-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 01/09/2023]
Abstract
In nature, bacteria form biofilms by producing exopolymeric matrix that encases its entire community. While it is widely known that biofilm matrix can prevent bacterivore predation and contain virulence factors for killing predators, it is unclear if they can alter predator motility. Here, we report a novel "quagmire" phenotype, where Pseudomonas aeruginosa biofilms could retard the motility of bacterivorous nematode Caenorhabditis elegans via the production of a specific exopolysaccharide, Psl. Psl could reduce the roaming ability of C. elegans by impeding the slithering velocity of C. elegans. Furthermore, the presence of Psl in biofilms could entrap C. elegans within the matrix, with dire consequences to the nematode. After being trapped in biofilms, C. elegans could neither escape effectively from aversive stimuli (noxious blue light), nor leave easily to graze on susceptible biofilm areas. Hence, this reduced the ability of C. elegans to roam and predate on biofilms. Taken together, our work reveals a new function of motility interference by specific biofilm matrix components, and emphasizes its importance in predator-prey interactions.
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Affiliation(s)
- Shepherd Yuen Chan
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Sylvia Yang Liu
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Zijing Seng
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Song Lin Chua
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China. .,State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
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21
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Badal D, Jayarani AV, Kollaran MA, Kumar A, Singh V. Pseudomonas aeruginosa biofilm formation on endotracheal tubes requires multiple two-component systems. J Med Microbiol 2020; 69:906-919. [PMID: 32459613 DOI: 10.1099/jmm.0.001199] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator.Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process.Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility.Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility.Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.
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Affiliation(s)
- Divakar Badal
- Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Abhijith Vimal Jayarani
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Mohammed Ameen Kollaran
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA.,Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Varsha Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA.,Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
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22
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Kovach KN, Fleming D, Wells MJ, Rumbaugh KP, Gordon VD. Specific Disruption of Established Pseudomonas aeruginosa Biofilms Using Polymer-Attacking Enzymes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:1585-1595. [PMID: 31990563 PMCID: PMC7063831 DOI: 10.1021/acs.langmuir.9b02188] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Biofilms are communities of bacteria embedded in a polymeric matrix which are found in infections and in environments outside the body. Breaking down the matrix renders biofilms more susceptible to physical disruption and to treatments such as antibiotics. Different species of bacteria, and different strains within the same species, produce different types of matrix polymers. This suggests that targeting specific polymers for disruption may be more effective than nonspecific approaches to disrupting biofilm matrixes. In this study, we treated Pseudomonas aeruginosa biofilms with enzymes that are specific to different matrix polymers. We measured the resulting alteration in biofilm mechanics using bulk rheology and changes in structure using electron microscopy. We find that, for biofilms grown in vitro, the effect of enzymatic treatment is greatest when the enzyme is specific to a dominant matrix polymer. Specifically matched enzymatic treatment tends to reduce yield strain and yield stress and increase the rate of biofilm drying, due to increased diffusivity as a result of network compromise. Electron micrographs qualitatively suggest that well-matched enzymatic treatments reduce long-range structure and shorten connecting network fibers. Previous work has shown that generic glycoside hydrolases can cause dispersal of bacteria from in vivo and ex vivo biofilms into a free-swimming state, and thereby make antibiotic treatment more effective. For biofilms grown in wounded mice, we find that well-matched treatments that result in the greatest mechanical compromise in vitro induce the least dispersal ex vivo. Moreover, we find that generic glycoside hydrolases have no measurable effect on the mechanics of biofilms grown in vitro, while previous work has shown them to be highly effective at inducing dispersal in vivo and ex vivo. This highlights the possibility that effective approaches to eradicating biofilms may depend strongly on the growth environment.
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Affiliation(s)
- Kristin N Kovach
- Department of Physics and Center for Nonlinear Dynamics , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Derek Fleming
- Department of Surgery , Texas Tech University Health Sciences Center , Lubbock , Texas 79430 , United States
| | - Marilyn J Wells
- Department of Physics and Center for Nonlinear Dynamics , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Kendra P Rumbaugh
- Department of Surgery , Texas Tech University Health Sciences Center , Lubbock , Texas 79430 , United States
| | - Vernita Diane Gordon
- Department of Physics and Center for Nonlinear Dynamics , The University of Texas at Austin , Austin , Texas 78712 , United States
- Institute for Cellular and Molecular Biology , The University of Texas at Austin , Austin , Texas 78712 , United States
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23
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Panmanee W, Su S, Schurr MJ, Lau GW, Zhu X, Ren Z, McDaniel CT, Lu LJ, Ohman DE, Muruve DA, Panos RJ, Yu HD, Thompson TB, Tseng BS, Hassett DJ. The anti-sigma factor MucA of Pseudomonas aeruginosa: Dramatic differences of a mucA22 vs. a ΔmucA mutant in anaerobic acidified nitrite sensitivity of planktonic and biofilm bacteria in vitro and during chronic murine lung infection. PLoS One 2019; 14:e0216401. [PMID: 31158231 PMCID: PMC6546240 DOI: 10.1371/journal.pone.0216401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 04/20/2019] [Indexed: 11/29/2022] Open
Abstract
Mucoid mucA22 Pseudomonas aeruginosa (PA) is an opportunistic lung pathogen of cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) patients that is highly sensitive to acidified nitrite (A-NO2-). In this study, we first screened PA mutant strains for sensitivity or resistance to 20 mM A-NO2- under anaerobic conditions that represent the chronic stages of the aforementioned diseases. Mutants found to be sensitive to A-NO2- included PA0964 (pmpR, PQS biosynthesis), PA4455 (probable ABC transporter permease), katA (major catalase, KatA) and rhlR (quorum sensing regulator). In contrast, mutants lacking PA0450 (a putative phosphate transporter) and PA1505 (moaA2) were A-NO2- resistant. However, we were puzzled when we discovered that mucA22 mutant bacteria, a frequently isolated mucA allele in CF and to a lesser extent COPD, were more sensitive to A-NO2- than a truncated ΔmucA deletion (Δ157–194) mutant in planktonic and biofilm culture, as well as during a chronic murine lung infection. Subsequent transcriptional profiling of anaerobic, A-NO2--treated bacteria revealed restoration of near wild-type transcript levels of protective NO2- and nitric oxide (NO) reductase (nirS and norCB, respectively) in the ΔmucA mutant in contrast to extremely low levels in the A-NO2--sensitive mucA22 mutant. Proteins that were S-nitrosylated by NO derived from A-NO2- reduction in the sensitive mucA22 strain were those involved in anaerobic respiration (NirQ, NirS), pyruvate fermentation (UspK), global gene regulation (Vfr), the TCA cycle (succinate dehydrogenase, SdhB) and several double mutants were even more sensitive to A-NO2-. Bioinformatic-based data point to future studies designed to elucidate potential cellular binding partners for MucA and MucA22. Given that A-NO2- is a potentially viable treatment strategy to combat PA and other infections, this study offers novel developments as to how clinicians might better treat problematic PA infections in COPD and CF airway diseases.
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Affiliation(s)
- Warunya Panmanee
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH United States of America
| | - Shengchang Su
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH United States of America
| | - Michael J. Schurr
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO United States of America
| | - Gee W. Lau
- College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL United States of America
| | - Xiaoting Zhu
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH United States of America
| | - Zhaowei Ren
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH United States of America
| | - Cameron T. McDaniel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH United States of America
| | - Long J. Lu
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH United States of America
| | - Dennis E. Ohman
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA United States of America
- McGuire Veterans Affairs Medical Center, Richmond, VA United States of America
| | - Daniel A. Muruve
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ralph J. Panos
- Department of Medicine, Cincinnati Veterans Affairs Medical Center, Cincinnati, OH United States of America
- Pulmonary, Critical Care, and Sleep Division, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH United States of America
| | - Hongwei D. Yu
- Department of Biochemistry and Microbiology, Marshall University, Huntington, WV United States of America
| | - Thomas B. Thompson
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH United States of America
| | - Boo Shan Tseng
- Department of Life Sciences, University of Nevada-Las Vegas, Las Vegas, NV United States of America
| | - Daniel J. Hassett
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH United States of America
- * E-mail:
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Bartell JA, Sommer LM, Haagensen JAJ, Loch A, Espinosa R, Molin S, Johansen HK. Evolutionary highways to persistent bacterial infection. Nat Commun 2019; 10:629. [PMID: 30733448 PMCID: PMC6367392 DOI: 10.1038/s41467-019-08504-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/10/2019] [Indexed: 01/18/2023] Open
Abstract
Persistent infections require bacteria to evolve from their naïve colonization state by optimizing fitness in the host via simultaneous adaptation of multiple traits, which can obscure evolutionary trends and complicate infection management. Accordingly, here we screen 8 infection-relevant phenotypes of 443 longitudinal Pseudomonas aeruginosa isolates from 39 young cystic fibrosis patients over 10 years. Using statistical modeling, we map evolutionary trajectories and identify trait correlations accounting for patient-specific influences. By integrating previous genetic analyses of 474 isolates, we provide a window into early adaptation to the host, finding: (1) a 2–3 year timeline of rapid adaptation after colonization, (2) variant “naïve” and “adapted” states reflecting discordance between phenotypic and genetic adaptation, (3) adaptive trajectories leading to persistent infection via three distinct evolutionary modes, and (4) new associations between phenotypes and pathoadaptive mutations. Ultimately, we effectively deconvolute complex trait adaptation, offering a framework for evolutionary studies and precision medicine in clinical microbiology. The pathogen Pseudomonas aeruginosa undergoes complex trait adaptation within cystic fibrosis patients. Here, Bartell, Sommer, and colleagues use statistical modeling of longitudinal isolates to characterize the joint genetic and phenotypic evolutionary trajectories of P. aeruginosa within hosts.
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Affiliation(s)
- Jennifer A Bartell
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark.
| | - Lea M Sommer
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen Ø, Denmark.
| | - Janus A J Haagensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Anne Loch
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Rocio Espinosa
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Søren Molin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen Ø, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen N, Denmark
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Pandey S, Delgado C, Kumari H, Florez L, Mathee K. Outer-membrane protein LptD (PA0595) plays a role in the regulation of alginate synthesis in Pseudomonas aeruginosa. J Med Microbiol 2018; 67:1139-1156. [PMID: 29923820 DOI: 10.1099/jmm.0.000752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The presence of alginate-overproducing (Alg+) strains of Pseudomonas aeruginosa in cystic fibrosis patients is indicative of chronic infection. The Alg+ phenotype is generally due to a mutation in the mucA gene, encoding an innermembrane protein that sequesters AlgT/U, the alginate-specific sigma factor. AlgT/U release from the anti-sigma factor MucA is orchestrated via a complex cascade called regulated intramembrane proteolysis. The goal of this study is to identify new players involved in the regulation of alginate production. METHODOLOGY Previously, a mutant with a second-site suppressor of alginate production (sap), sap27, was isolated from the constitutively Alg+ PDO300 that harbours the mucA22 allele. A cosmid from a P. aeruginosa minimum tiling path library was identified via en masse complementation of sap27. The cosmid was transposon mutagenized to map the contributing gene involved in the alginate production. The identified gene was sequenced in sap27 along with algT/U, mucA, algO and mucP. The role of the novel gene was explored using precise in-frame algO and algW deletion mutants of PAO1 and PDO300.Results/Key findings. The gene responsible for restoring the mucoid phenotype was mapped to lptD encoding an outer-membrane protein. However, the sequencing of sap27 revealed a mutation in algO, but not in lptD. In addition, we demonstrate that lipopolysaccharide transport protein D (LptD)-dependent alginate production requires AlgW in PAO1 and AlgO in PDO300. CONCLUSION LptD plays a specific role in alginate production. Our findings suggest that there are two pathways for the production of alginate in P. aeruginosa, one involving AlgW in the wild-type, and one involving AlgO in the mucA22 mutant.
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Affiliation(s)
- Sundar Pandey
- 1Department of Biological Sciences, College of Arts Sciences and Education, Florida International University, Miami, FL, USA
| | - Camila Delgado
- 2Department of Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,†Present address: Langone Medical Center, New York University School of Medicine, New York, USA
| | - Hansi Kumari
- 2Department of Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,3Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Laura Florez
- 2Department of Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Kalai Mathee
- 4Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.,2Department of Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,3Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
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Vidaillac C, Yong VFL, Jaggi TK, Soh MM, Chotirmall SH. Gender differences in bronchiectasis: a real issue? Breathe (Sheff) 2018; 14:108-121. [PMID: 29875830 PMCID: PMC5980467 DOI: 10.1183/20734735.000218] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Gender differences in chronic respiratory disease, including cystic fibrosis and non-cystic fibrosis bronchiectasis are clinically apparent and of increasing importance. Differences in disease prevalence, severity and outcome are all described, however, the precise cause of the gender dichotomy and their associated underlying mechanisms have been poorly characterised. A lack of dedicated clinical and epidemiological research focused in this area has led to a paucity of data and therefore a lack of understanding of its key drivers. Diagnosis, disease pathogenesis and treatment response are all complex but important aspects of bronchiectasis with an evident gender bias. Broadening our understanding of the interplay between microbiology, host physiology and the environment in the context of chronic lung diseases, such as bronchiectasis, is critical to unravelling mechanisms driving the observed gender differences. In this review, epidemiological, biological and environmental evidence related to gender in bronchiectasis is summarised. This illustrates gender differences as a “real issue” with the objective of mapping out a future framework upon which a gender-tailored medical approach may be incorporated into the diagnosis, monitoring and treatment of bronchiectasis. CF and non-CF bronchiectasis are complex multifactorial chronic pulmonary diseases demonstrating gender differences in their prevalence, severity and infections, some of which are attributable to sex hormoneshttp://ow.ly/beDf30jseK4
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Affiliation(s)
- Celine Vidaillac
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Valerie F L Yong
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Tavleen K Jaggi
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Min-Min Soh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Sanjay H Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
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Meyle E, Stroh P, GüNther F, Hoppy-Tichy T, Wagner C, HäNsch GM. Destruction of Bacterial Biofilms by Polymorphonuclear Neutrophils: Relative contribution of Phagocytosis, DNA Release, and Degranulation. Int J Artif Organs 2018; 33:608-20. [DOI: 10.1177/039139881003300906] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2010] [Indexed: 12/13/2022]
Abstract
Bacteria organized in biofilms are a common cause of relapsing or persistent infections, and the ultimate cause of implant-associated osteomyelitis. In these patients, biofilms of staphylococci are prevalent. Bacteria organized as biofilms are relatively resistant towards antibiotics and biocides, and it is also assumed that they may escape host defense mechanisms. In this context, we have studied how polymorphonuclear neutrophils (PMN), the “first line of defense” against bacterial infection, interact with biofilms generated in vitro. We found that PMN recognize biofilms and activate defense-associated reactions, including phagocytosis, degranulation of lactoferrin and elastase, and DNA release as well. Destruction of biofilms ensues, showing that biofilms are not inherently protected against the attack by phagocytic cells.
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Affiliation(s)
- Eva Meyle
- Institute of Immunology, University of Heidelberg, Heidelberg - Germany
- Institute of Pharmacy, University of Heidelberg, Heidelberg - Germany
| | - Petra Stroh
- Institute of Immunology, University of Heidelberg, Heidelberg - Germany
| | - Frank GüNther
- Institute of Immunology, University of Heidelberg, Heidelberg - Germany
| | | | - Christof Wagner
- Department of Trauma Surgery and Orthopedic Surgery, BG Trauma Clinic Ludwigshafen, Ludwigshafen - Germany
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The Extracellular Polymer Substance of Pseudomonas Aeruginosa: Too slippery for Neutrophils to Migrate On? Int J Artif Organs 2018; 31:796-803. [DOI: 10.1177/039139880803100907] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose Biofilm formation is increasingly recognized as the cause of persistent infections and there is evidence that P. aeruginosa organized into biofilms are quite resistant toward host defence mechanisms, particularly against an attack by polymorphonuclear neutrophils (PMN). Apparently, the migration of PMN through the biofilms is impaired, and thus the bactericidal activity remains highly localized. The aim of this study was to directly investigate the interaction of PMN with the biofilm and the extracted extracellular polymeric substance (EPS) of P. aeruginosa. Material and Methods Chemotaxis and random migration of PMN through P. aeruginosa biofilms was tested, as was their migration through and along the EPS. Results We found that the EPS and mature biofilms, but not immature or developing ones, reduced the chemotactic migration of PMN. On EPS, rather than immobilize the cells, their random, spontaneous migration was enhanced. Conclusion We propose that on EPS, the PMN lose their capacity to sense the direction and just slide over the EPS in a disoriented manner. (Int J Artif Organs 2008; 31: 796–803)
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KB001-A, a novel anti-inflammatory, found to be safe and well-tolerated in cystic fibrosis patients infected with Pseudomonas aeruginosa. J Cyst Fibros 2017; 17:484-491. [PMID: 29292092 DOI: 10.1016/j.jcf.2017.12.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND Chronic Pseudomonas aeruginosa (Pa) airways infection, exuberant local inflammation, and progressive lung function loss are hallmarks of cystic fibrosis (CF). KB001-A is an anti-PcrV PEGylated monoclonal antibody fragment to the Type III secretion system of Pa. This 16-week study evaluated KB001-A associated effect on time-to-need for antibiotics for worsening respiratory signs and symptoms, as well as safety, and treatment-associated changes in symptom scores, inflammatory markers, and spirometry. METHODS This was a randomized, double-blind, placebo-controlled, repeat-dose study in CF subjects with Pa. Intravenous 10mg/kg KB001-A or placebo infusions were administered at baseline and weeks 2, 4, 8, and 16, with a 4-week follow-up. Sputum inflammatory markers were assessed in a sub-study. Time-to-need for antibiotics was compared between groups by Kaplan Meier analysis and Cox proportional hazards modeling adjusting for randomization strata. RESULTS Of 182 subjects, 169 received at least one infusion of KB001-A (n=83) or placebo (n=86). KB001-A was generally safe and well-tolerated as compared to placebo, with no significant emergent adverse effects other than one serious adverse event of elevated hepatic enzymes of unclear etiology. Time to need for antibiotics did not differ between groups (HR: 1.00; 95% CI: 0.69, 1.45, p=0.995). A 3.2 increase in ppFEV1 from placebo favoring KB001-A was observed at week 16 (95% CI: 1.12, 5.30, p=0.003). Mean changes from baseline in log10 sputum neutrophil elastase (NE) had a non-significant decrease (-0.27, 95% CI: -0.58,0.04, p=0.084) while IL-8 concentrations at week 16 were significantly lower (-0.27, 95% CI: -0.55,0.00, p=0.048) among KB001-A subjects (n=16) relative to placebo (n=13). CONCLUSIONS KB001-A was safe and well-tolerated and associated with a modest FEV1 benefit and reduction in select sputum inflammatory markers (IL-8). KB001-A was not associated with an increased time to need for antibiotics. The lack of efficacy seen with KB001-A may be due, in part, to the low levels of the type III secretion proteins previously reported in sputum of CF patients chronically infected with Pa.
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Zhou E, Seminara AB, Kim SK, Hall CL, Wang Y, Lee VT. Thiol-benzo-triazolo-quinazolinone Inhibits Alg44 Binding to c-di-GMP and Reduces Alginate Production by Pseudomonas aeruginosa. ACS Chem Biol 2017; 12:3076-3085. [PMID: 29091392 DOI: 10.1021/acschembio.7b00826] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that affects a large proportion of cystic fibrosis (CF) patients. CF patients have dehydrated mucus within the airways that leads to the inability of the mucociliary escalator to expel inhaled microbes. Once inhaled, P. aeruginosa can persist in the lungs of the CF patients for the remainder of their lives. During this chronic infection, a phenomenon called mucoid conversion can occur in which P. aeruginosa can mutate and inactivate their mucA gene. As a consequence, transcription of the alg operon is highly expressed, leading to the copious secretion of the alginate exopolysaccharide, which is associated with decreased lung function and increased CF patient morbidity and mortality. Alginate biosynthesis by P. aeruginosa is post-translationally regulated by bis(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), which binds to the receptor protein Alg44 to activate alginate production. The identification of small molecules that disrupt the binding of c-di-GMP to Alg44 could inhibit the ability of P. aeruginosa to produce alginate. In this work, a class of thiol-benzo-triazolo-quinazolinone compounds that inhibited Alg44 binding to c-di-GMP in vitro was identified after screening chemical libraries consisting of ∼50 000 chemical compounds. Thiol-benzo-triazolo-quinazolinones were shown to specifically inhibit Alg44-c-di-GMP interactions by forming a disulfide bond with the cysteine residue in the PilZ domain of Alg44. The more potent thiol-benzo-triazolo-quinazolinone had the ability to reduce P. aeruginosa alginate secretion by up to 30%. These compounds serve as leads in the development of novel inhibitors of alginate production by P. aeruginosa after mucoid conversion.
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Affiliation(s)
- Eric Zhou
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Anna B. Seminara
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Soo-Kyoung Kim
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Cherisse L. Hall
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Yan Wang
- Maryland Pathogen Research Institute, Bioscience Research Building, College Park, Maryland 20742, United States
- Proteomics
Core Facility, College of Computer, Mathematical and Natural Science, University of Maryland College Park, 0111 Biology Psychology Building, College Park, Maryland 20742, United States
| | - Vincent T. Lee
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
- Maryland Pathogen Research Institute, Bioscience Research Building, College Park, Maryland 20742, United States
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Evolutionary adaptations of biofilms infecting cystic fibrosis lungs promote mechanical toughness by adjusting polysaccharide production. NPJ Biofilms Microbiomes 2017. [PMID: 28649402 PMCID: PMC5445605 DOI: 10.1038/s41522-016-0007-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Biofilms are communities of microbes embedded in a matrix of extracellular polymeric substances, largely polysaccharides. Multiple types of extracellular polymeric substances can be produced by a single bacterial strain. The distinct polymer components of biofilms are known to provide chemical protection, but little is known about how distinct extracellular polysaccharides may also protect biofilms against mechanical stresses such as shear or phagocytic engulfment. Decades-long infections of Pseudomonas. aeruginosa biofilms in the lungs of cystic fibrosis patients are natural models for studies of biofilm fitness under pressure from antibiotics and the immune system. In cystic fibrosis infections, production of the extracellular polysaccharide alginate has long been known to increase with time and to chemically protect biofilms. More recently, it is being recognized that chronic cystic fibrosis infections also evolve to increase production of another extracellular polysaccharide, Psl; much less is known about Psl’s protective benefits to biofilms. We use oscillatory bulk rheology, on biofilms grown from longitudinal clinical isolates and from genetically-manipulated lab strains, to show that increased Psl stiffens biofilms and increases biofilm toughness, which is the energy cost to cause the biofilm to yield mechanically. Further, atomic force microscopy measurements reveal greater intercellular cohesion for higher Psl expression. Of the three types of extracellular polysaccharides produced by P. aeruginosa, only Psl increases the stiffness. Stiffening by Psl requires CdrA, a protein that binds to mannose groups on Psl and is a likely cross-linker for the Psl components of the biofilm matrix. We compare the elastic moduli of biofilms to the estimated stresses exerted by neutrophils during phagocytosis, and infer that increased Psl could confer a mechanical protection against phagocytic clearance. Bacteria in lungs of people with cystic fibrosis can evolve through decades to build a tough biofilm that resists the body’s defences. Vernita Gordon and colleagues at the University of Texas, with co-workers in Europe, examined biofilms cultured from lung samples taken from patients at intervals over many years. The infecting bacterial populations had steadily evolved to increase production of specific carbohydrate components of the biofilms. The researchers found that increasing production of one carbohydrate component strengthens the biofilms, most likely due to the carbohydrate being crosslinked by protein molecules. The investigation suggests that the mechanics of the carbohydrate-protein network protects the biofilms from being broken into smaller pieces that can be engulfed by defensive cells called phagocytes. This new insight into the evolution of mechanical toughness complements the previously observed evolution of increasing chemical protection. Understanding these processes will assist efforts to combat them.
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Colmer-Hamood JA, Dzvova N, Kruczek C, Hamood AN. In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 142:151-91. [PMID: 27571695 DOI: 10.1016/bs.pmbts.2016.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections.
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Affiliation(s)
- J A Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
| | - N Dzvova
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - C Kruczek
- Honors College, Texas Tech University, Lubbock, TX, United States
| | - A N Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
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Xu X, Yu H, Zhang D, Xiong J, Qiu J, Xin R, He X, Sheng H, Cai W, Jiang L, Zhang K, Hu X. Role of ppGpp in Pseudomonas aeruginosa acute pulmonary infection and virulence regulation. Microbiol Res 2016; 192:84-95. [PMID: 27664726 DOI: 10.1016/j.micres.2016.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 11/28/2022]
Abstract
During infection, bacteria might generate adaptive responses to facilitate their survival and colonization in the host environment. The alarmone guanosine 5'-triphosphate-3'-diphosphate (ppGpp), the levels of which are regulated by the RelA and SpoT enzymes, plays a critical role in mediating bacterial adaptive responses and virulence. However, the mechanism by which ppGpp regulates virulence-associated traits in Pseudomonas aeruginosa is poorly understood. To investigate the regulatory role of ppGpp, the ppGpp-deficient strain ΔRS (relA and spoT gene double mutant) and the complemented strain ΔRS(++) (complemented with relA and spoT genes) were constructed. Herein, we reported that the ΔRS strain showed decreased cytotoxicity towards A549 human alveolar adenocarcinoma cell lines and led to reduced mortality, lung edema and inflammatory cell infiltration in a mouse model of acute pneumonia compared to wild-type PAO1 and the complemented strain ΔRS(++). Subsequent analyses demonstrated that the ΔRS strain displayed reduced T3SS expression, decreased levels of elastase activity, pyocyanin, pyoverdin and alginate, and inhibited swarming and biofilm formation compared to PAO1 and the complemented strain ΔRS(++). In addition, the results demonstrate that ppGpp-mediated regulation of T3SS, virulence factor production, and swarming occurs in a quinolone quorum-sensing system-dependent manner. Taken together, these results suggest that ppGpp is required for virulence regulation in P. aeruginosa, providing new clues for the development of interference strategies against bacterial infection.
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Affiliation(s)
- Xiaohui Xu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Hua Yu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Di Zhang
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Junzhi Xiong
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jing Qiu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Rong Xin
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Xiaomei He
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Halei Sheng
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Wenqiang Cai
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Lu Jiang
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Kebin Zhang
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
| | - Xiaomei Hu
- Central Laboratory, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.
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Alves D, Sileika T, Messersmith PB, Pereira MO. Polydopamine-Mediated Immobilization of Alginate Lyase to Prevent P. aeruginosa Adhesion. Macromol Biosci 2016; 16:1301-10. [PMID: 27198822 DOI: 10.1002/mabi.201600077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 04/18/2016] [Indexed: 11/06/2022]
Abstract
Given alginate's contribution to Pseudomonas aeruginosa virulence, it has long been considered a promising target for interventional therapies, which have been performed by using the enzyme alginate lyase. In this work, instead of treating pre-established mucoid biofilms, alginate lyase is immobilized onto a surface as a preventive measure against P. aeruginosa adhesion. A polydopamine dip-coating strategy is employed for functionalization of polycarbonate surfaces. Enzyme immobilization is confirmed by surface characterization. Surfaces functionalized with alginate lyase exhibit anti-adhesive properties, inhibiting the attachment of the mucoid strain. Moreover, surfaces modified with this enzyme also inhibit the adhesion of the tested non-mucoid strain. Unexpectedly, treatment with heat-inactivated enzyme also inhibits the attachment of mucoid and non-mucoid P. aeruginosa strains. These findings suggest that the antibacterial performance of alginate lyase functional coatings is catalysis-independent, highlighting the importance of further studies to better understand its mechanism of action against P. aeruginosa strains.
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Affiliation(s)
- Diana Alves
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
| | - Tadas Sileika
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Phillip B Messersmith
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.,Department of Bioengineering and Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720-1760, USA
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
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Anti- Pseudomonas aeruginosa IgY antibodies augment bacterial clearance in a murine pneumonia model. J Cyst Fibros 2016; 15:171-8. [DOI: 10.1016/j.jcf.2015.08.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/01/2015] [Accepted: 08/06/2015] [Indexed: 01/08/2023]
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Biofilm formation mechanisms and targets for developing antibiofilm agents. Future Med Chem 2016; 7:493-512. [PMID: 25875875 DOI: 10.4155/fmc.15.6] [Citation(s) in RCA: 367] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Biofilms are communities of microorganisms that are attached to a surface and play a significant role in the persistence of bacterial infections. Bacteria within a biofilm are several orders of magnitude more resistant to antibiotics, compared with planktonic bacteria. Thus far, no drugs are in clinical use that specifically target bacterial biofilms. This is probably because until recently the molecular details of biofilm formation were poorly understood. Bacteria integrate information from the environment, such as quorum-sensing autoinducers and nutrients, into appropriate biofilm-related gene expression, and the identity of the key players, such as cyclic dinucleotide second messengers and regulatory RNAs are beginning to be uncovered. Herein, we highlight the current understanding of the processes that lead to biofilm formation in many bacteria.
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Duong J, Booth SC, McCartney NK, Rabin HR, Parkins MD, Storey DG. Phenotypic and Genotypic Comparison of Epidemic and Non-Epidemic Strains of Pseudomonas aeruginosa from Individuals with Cystic Fibrosis. PLoS One 2015; 10:e0143466. [PMID: 26599104 PMCID: PMC4657914 DOI: 10.1371/journal.pone.0143466] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/05/2015] [Indexed: 11/18/2022] Open
Abstract
Epidemic strains of Pseudomonas aeruginosa have been found worldwide among the cystic fibrosis (CF) patient population. Using pulse-field gel electrophoresis, the Prairie Epidemic Strain (PES) has recently been found in one-third of patients attending the Calgary Adult CF Clinic in Canada. Using multi-locus sequence typing, PES isolates from unrelated patients were found to consistently have ST192. Though most patients acquired PES prior to enrolling in the clinic, some patients were observed to experience strain replacement upon transitioning to the clinic whereby local non-epidemic P. aeruginosa isolates were displaced by PES. Here we genotypically and phenotypically compared PES to other P. aeruginosa epidemic strains (OES) found around the world as well as local non-epidemic CF P. aeruginosa isolates in order to characterize PES. Since some epidemic strains are associated with worse clinical outcomes, we assessed the pathogenic potential of PES to determine if these isolates are virulent, shared properties with OES, and if its phenotypic properties may offer a competitive advantage in displacing local non-epidemic isolates during strain replacement. As such, we conducted a comparative analysis using fourteen phenotypic traits, including virulence factor production, biofilm formation, planktonic growth, mucoidy, and antibiotic susceptibility to characterize PES, OES, and local non-epidemic isolates. We observed that PES and OES could be differentiated from local non-epidemic isolates based on biofilm growth with PES isolates being more mucoid. Pairwise comparisons indicated that PES produced significantly higher levels of proteases and formed better biofilms than OES but were more susceptible to antibiotic treatment. Amongst five patients experiencing strain replacement, we found that super-infecting PES produced lower levels of proteases and elastases but were more resistant to antibiotics compared to the displaced non-epidemic isolates. This comparative analysis is the first to be completed on a large scale between groups of epidemic and non-epidemic CF P. aeruginosa isolates.
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Affiliation(s)
- Jessica Duong
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Sean C. Booth
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Nathan K. McCartney
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Harvey R. Rabin
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael D. Parkins
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Douglas G. Storey
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
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Jackson LMD, Kroukamp O, Wolfaardt GM. Effect of carbon on whole-biofilm metabolic response to high doses of streptomycin. Front Microbiol 2015; 6:953. [PMID: 26441887 PMCID: PMC4566048 DOI: 10.3389/fmicb.2015.00953] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/28/2015] [Indexed: 01/10/2023] Open
Abstract
Biofilms typically exist as complex communities comprising multiple species with the ability to adapt to a variety of harsh conditions. In clinical settings, antibiotic treatments based on planktonic susceptibility tests are often ineffective against biofilm infections. Using a CO2 evolution measurement system we delineated the real-time metabolic response in continuous flow biofilms to streptomycin doses much greater than their planktonic susceptibilities. Stable biofilms from a multispecies culture (containing mainly Pseudomonas aeruginosa and Stenotrophomonas maltophilia), Gram-negative environmental isolates, and biofilms formed by pure culture P. aeruginosa strains PAO1 and PAO1 ΔMexXY (minimum planktonic inhibitory concentrations between 1.5 and 3.5 mg/l), were exposed in separate experiments to 4000 mg/l streptomycin for 4 h after which growth medium resumed. In complex medium, early steady state multispecies biofilms were susceptible to streptomycin exposure, inferred by a cessation of CO2 production. However, multispecies biofilms survived high dose exposures when there was extra carbon in the antibiotic medium, or when they were grown in defined citrate medium. The environmental isolates and PAO1 biofilms showed similar metabolic profiles in response to streptomycin; ceasing CO2 production after initial exposure, with CO2 levels dropping toward baseline levels prior to recovery back to steady state levels, while subsequent antibiotic exposure elicited increased CO2 output. Monitoring biofilm metabolic response in real-time allowed exploration of conditions resulting in vulnerability after antibiotic exposure compared to the resistance displayed following subsequent exposures.
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Affiliation(s)
| | - Otini Kroukamp
- Department of Chemistry and Biology, Ryerson University, Toronto ON, Canada
| | - Gideon M Wolfaardt
- Department of Chemistry and Biology, Ryerson University, Toronto ON, Canada ; Department of Microbiology, Stellenbosch University Stellenbosch, South Africa
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Thomsen K, Christophersen L, Bjarnsholt T, Jensen PØ, Moser C, Høiby N. Anti-Pseudomonas aeruginosa IgY Antibodies Induce Specific Bacterial Aggregation and Internalization in Human Polymorphonuclear Neutrophils. Infect Immun 2015; 83:2686-93. [PMID: 25895968 PMCID: PMC4468541 DOI: 10.1128/iai.02970-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 04/10/2015] [Indexed: 01/24/2023] Open
Abstract
Polymorphonuclear neutrophils (PMNs) are essential cellular constituents in the innate host response, and their recruitment to the lungs and subsequent ubiquitous phagocytosis controls primary respiratory infection. Cystic fibrosis pulmonary disease is characterized by progressive pulmonary decline governed by a persistent, exaggerated inflammatory response dominated by PMNs. The principal contributor is chronic Pseudomonas aeruginosa biofilm infection, which attracts and activates PMNs and thereby is responsible for the continuing inflammation. Strategies to prevent initial airway colonization with P. aeruginosa by augmenting the phagocytic competence of PMNs may postpone the deteriorating chronic biofilm infection. Anti-P. aeruginosa IgY antibodies significantly increase the PMN-mediated respiratory burst and subsequent bacterial killing of P. aeruginosa in vitro. The mode of action is attributed to IgY-facilitated formation of immobilized bacteria in aggregates, as visualized by fluorescence microscopy and the induction of increased bacterial hydrophobicity. Thus, the present study demonstrates that avian egg yolk immunoglobulins (IgY) targeting P. aeruginosa modify bacterial fitness, which enhances bacterial killing by PMN-mediated phagocytosis and thereby may facilitate a rapid bacterial clearance in airways of people with cystic fibrosis.
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Affiliation(s)
- K Thomsen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - L Christophersen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - T Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, Copenhagen, Denmark
| | - P Ø Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - C Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - N Høiby
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, Copenhagen, Denmark
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Abstract
The molecular mechanisms of alginate polymerization/modification/secretion by a proposed envelope-spanning multiprotein complex are unknown. Here, bacterial two-hybrid assays and pulldown experiments showed that the catalytic subunit Alg8 directly interacts with the proposed copolymerase Alg44 while embedded in the cytoplasmic membrane. Alg44 additionally interacts with the lipoprotein AlgK bridging the periplasmic space. Site-specific mutagenesis of Alg44 showed that protein-protein interactions and stability were independent of conserved amino acid residues R17 and R21, which are involved in c-di-GMP binding, the N-terminal PilZ domain, and the C-terminal 26 amino acids. Site-specific mutagenesis was employed to investigate the c-di-GMP-mediated activation of alginate polymerization by the PilZAlg44 domain and Alg8. Activation was found to be different from the proposed activation mechanism for cellulose synthesis. The interactive role of Alg8, Alg44, AlgG (epimerase), and AlgX (acetyltransferase) on alginate polymerization and modification was studied by using site-specific deletion mutants, inactive variants, and overproduction of subunits. The compositions, molecular masses, and material properties of resulting novel alginates were analyzed. The molecular mass was reduced by epimerization, while it was increased by acetylation. Interestingly, when overproduced, Alg44, AlgG, and the nonepimerizing variant AlgG(D324A) increased the degree of acetylation, while epimerization was enhanced by AlgX and its nonacetylating variant AlgX(S269A). Biofilm architecture analysis showed that acetyl groups promoted cell aggregation while nonacetylated polymannuronate alginate promoted stigmergy. Overall, this study sheds new light on the arrangement of the multiprotein complex involved in alginate production. Furthermore, the activation mechanism and the interplay between polymerization and modification of alginate were elucidated. This study provides new insights into the molecular mechanisms of the synthesis of the unique polysaccharide, alginate, which not only is an important virulence factor of the opportunistic human pathogen Pseudomonas aeruginosa but also has, due to its material properties, many applications in medicine and industry. Unraveling the assembly and composition of the alginate-synthesizing and envelope-spanning multiprotein complex will be of tremendous significance for the scientific community. We identified a protein-protein interaction network inside the multiprotein complex and studied its relevance with respect to alginate polymerization/modification as well as the c-di-GMP-mediated activation mechanism. A relationship between alginate polymerization and modification was shown. Due to the role of alginate in pathogenesis as well as its unique material properties harnessed in numerous applications, results obtained in this study will aid the design and development of inhibitory drugs as well as the commercial bacterial production of tailor-made alginates.
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Ciofu O, Tolker-Nielsen T, Jensen PØ, Wang H, Høiby N. Antimicrobial resistance, respiratory tract infections and role of biofilms in lung infections in cystic fibrosis patients. Adv Drug Deliv Rev 2015; 85:7-23. [PMID: 25477303 DOI: 10.1016/j.addr.2014.11.017] [Citation(s) in RCA: 206] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 11/11/2014] [Accepted: 11/23/2014] [Indexed: 02/08/2023]
Abstract
Lung infection is the main cause of morbidity and mortality in patients with cystic fibrosis and is mainly dominated by Pseudomonas aeruginosa. The biofilm mode of growth makes eradication of the infection impossible, and it causes a chronic inflammation in the airways. The general mechanisms of biofilm formation and antimicrobial tolerance and resistance are reviewed. Potential anti-biofilm therapeutic targets such as weakening of biofilms by quorum-sensing inhibitors or antibiotic killing guided by pharmacokinetics and pharmacodynamics of antibiotics are presented. The vicious circle of adaptive evolution of the persisting bacteria imposes important therapeutic challenges and requires development of new drug delivery systems able to reach the different niches occupied by the bacteria in the lung of cystic fibrosis patients.
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Conrad DJ, Bailey BA. Multidimensional clinical phenotyping of an adult cystic fibrosis patient population. PLoS One 2015; 10:e0122705. [PMID: 25822311 PMCID: PMC4378917 DOI: 10.1371/journal.pone.0122705] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/19/2015] [Indexed: 12/04/2022] Open
Abstract
Background Cystic Fibrosis (CF) is a multi-systemic disease resulting from mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene and has major manifestations in the sino-pulmonary, and gastro-intestinal tracts. Clinical phenotypes were generated using 26 common clinical variables to generate classes that overlapped quantiles of lung function and were based on multiple aspects of CF systemic disease. Methods The variables included age, gender, CFTR mutations, FEV1% predicted, FVC% predicted, height, weight, Brasfield chest xray score, pancreatic sufficiency status and clinical microbiology results. Complete datasets were compiled on 211 subjects. Phenotypes were identified using a proximity matrix generated by the unsupervised Random Forests algorithm and subsequent clustering by the Partitioning around Medoids (PAM) algorithm. The final phenotypic classes were then characterized and compared to a similar dataset obtained three years earlier. Findings Clinical phenotypes were identified using a clustering strategy that generated four and five phenotypes. Each strategy identified 1) a low lung health scores phenotype, 2) a younger, well-nourished, male-dominated class, 3) various high lung health score phenotypes that varied in terms of age, gender and nutritional status. This multidimensional clinical phenotyping strategy identified classes with expected microbiology results and low risk clinical phenotypes with pancreatic sufficiency. Interpretation This study demonstrated regional adult CF clinical phenotypes using non-parametric, continuous, ordinal and categorical data with a minimal amount of subjective data to identify clinically relevant phenotypes. These studies identified the relative stability of the phenotypes, demonstrated specific phenotypes consistent with published findings and identified others needing further study.
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Affiliation(s)
- Douglas J. Conrad
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
| | - Barbara A. Bailey
- Department of Mathematics and Statistics, San Diego State University, San Diego, California, United States of America
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Farjah A, Owlia P, Siadat SD, Mousavi SF, Ardestani MS, Mohammadpour HK. Immunological evaluation of an alginate-based conjugate as a vaccine candidate againstPseudomonas aeruginosa. APMIS 2014; 123:175-83. [DOI: 10.1111/apm.12337] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 09/30/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Ali Farjah
- Department of Biology; Shahed University; Tehran Iran
- Department of Microbiology; Microbial research center; Pasteur Institute of Iran; Tehran Iran
| | - Parviz Owlia
- Molecular Microbiology Research Center; Shahed University; Tehran Iran
| | - Seyed Davar Siadat
- Department of Microbiology; Microbial research center; Pasteur Institute of Iran; Tehran Iran
| | - Seyed Fazlollah Mousavi
- Department of Microbiology; Microbial research center; Pasteur Institute of Iran; Tehran Iran
| | - Mehdi Shafiee Ardestani
- Department of Radiopharmacy; Faculty of pharmacy; Tehran University of Medical Science; Tehran Iran
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Farjah A, Owlia P, Siadat SD, Mousavi SF, Shafieeardestani M. Conjugation of alginate to a synthetic peptide containing T- and B-cell epitopes as an induction for protective immunity against Pseudomonas aeruginosa. J Biotechnol 2014; 192 Pt A:240-7. [DOI: 10.1016/j.jbiotec.2014.10.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/14/2014] [Accepted: 10/20/2014] [Indexed: 11/26/2022]
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Kumar L, Chhibber S, Harjai K. Structural alterations in Pseudomonas aeruginosa by zingerone contribute to enhanced susceptibility to antibiotics, serum and phagocytes. Life Sci 2014; 117:24-32. [PMID: 25277943 DOI: 10.1016/j.lfs.2014.09.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/14/2014] [Accepted: 09/17/2014] [Indexed: 11/15/2022]
Abstract
AIMS Excessive use of antibiotics has led to evolutionary adaptation resulting in emergence of multidrug resistance in P. aeruginosa. The aim of the present study was oriented towards exploiting zingerone (active component of ginger) in making P. aeruginosa more susceptible to killing with antibiotics, humoral/cellular defences and studying its underlying mechanism. MAIN METHOD Effect of zingerone treatment on antibiotic susceptibility, serum, and phagocytic killing of P. aeruginosa was studied. The underlying mechanism was evaluated in terms of cell surface hydrophobicity, alginate and LPS production. TNF-α and MIP-2 cytokine production by mouse macrophages was also checked. Structural analysis was carried out using scanning electron microscopy (SEM) and liquid chromatography-mass spectrometry (LC-MS) analysis. KEY FINDINGS Zingerone treated cells showed increased susceptibility to variety of antibiotics, serum as well as macrophages (p<0.05). Zingerone treatment significantly reduced cell surface hydrophobicity, alginate and LPS production (p<0.05). Zingerone treated cells showed significant decrease in TNF-α and MIP-2 cytokine production as compared to non-treated cells. Coupled with this, reduction in the production of extracellular protective matrix and modulation of chemical structure of LPS was also observed by scanning electron microscopy and liquid chromatography-mass spectrometric (LC-MS) respectively. Zingerone significantly influence surface structure of P. aeruginosa which contributes towards enhanced susceptibility to antibiotics and innate immune system. SIGNIFICANCE Use of phytochemicals may prove to be a novel therapeutic approach by enhancing susceptibility of pathogenic microorganisms to antibiotics and immune system. Zingerone has proved to be one such agent which can be employed as a potential anti-virulent drug candidate against P. aeruginosa infections.
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Affiliation(s)
- Lokender Kumar
- Department of Microbiology, BMS Block, Panjab University, Chandigarh 160014, India
| | - Sanjay Chhibber
- Department of Microbiology, BMS Block, Panjab University, Chandigarh 160014, India
| | - Kusum Harjai
- Department of Microbiology, BMS Block, Panjab University, Chandigarh 160014, India.
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Environmental heterogeneity drives within-host diversification and evolution of Pseudomonas aeruginosa. mBio 2014; 5:e01592-14. [PMID: 25227464 PMCID: PMC4172072 DOI: 10.1128/mbio.01592-14] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial population polymorphisms are commonly observed in natural environments, including long-term infected hosts. However, the underlying processes promoting and stabilizing diversity are difficult to unravel and are not well understood. Here, we use chronic infection of cystic fibrosis airways by the opportunistic pathogen Pseudomonas aeruginosa as a system for investigating bacterial diversification processes during the course of infection. We analyze clonal bacterial isolates sampled during a 32-year period and map temporal and spatial variations in population diversity to different infection sites within the infected host. We show that the ancestral infecting strain diverged into distinct sublineages, each with their own functional and genomic signatures and rates of adaptation, immediately after initial colonization. The sublineages coexisted in the host for decades, suggesting rapid evolution of stable population polymorphisms. Critically, the observed generation and maintenance of population diversity was the result of partitioning of the sublineages into physically separated niches in the CF airway. The results reveal a complex within-host population structure not previously realized and provide evidence that the heterogeneity of the highly structured and complex host environment promotes the evolution and long-term stability of pathogen population diversity during infection. Within-host pathogen evolution and diversification during the course of chronic infections is of importance in relation to therapeutic intervention strategies, yet our understanding of these processes is limited. Here, we investigate intraclonal population diversity in P. aeruginosa during chronic airway infections in cystic fibrosis patients. We show the evolution of a diverse population structure immediately after initial colonization, with divergence into multiple distinct sublineages that coexisted for decades and occupied distinct niches. Our results suggest that the spatial heterogeneity in CF airways plays a major role in relation to the generation and maintenance of population diversity and emphasize that a single isolate in sputum may not represent the entire pathogen population in the infected individual. A more complete understanding of the evolution of distinct clonal variants and their distribution in different niches could have positive implications for efficient therapy.
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Chew SC, Kundukad B, Seviour T, van der Maarel JRC, Yang L, Rice SA, Doyle P, Kjelleberg S. Dynamic remodeling of microbial biofilms by functionally distinct exopolysaccharides. mBio 2014; 5:e01536-14. [PMID: 25096883 PMCID: PMC4128364 DOI: 10.1128/mbio.01536-14] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/07/2014] [Indexed: 12/24/2022] Open
Abstract
Biofilms are densely populated communities of microbial cells protected and held together by a matrix of extracellular polymeric substances. The structure and rheological properties of the matrix at the microscale influence the retention and transport of molecules and cells in the biofilm, thereby dictating population and community behavior. Despite its importance, quantitative descriptions of the matrix microstructure and microrheology are limited. Here, particle-tracking microrheology in combination with genetic approaches was used to spatially and temporally study the rheological contributions of the major exopolysaccharides Pel and Psl in Pseudomonas aeruginosa biofilms. Psl increased the elasticity and effective cross-linking within the matrix, which strengthened its scaffold and appeared to facilitate the formation of microcolonies. Conversely, Pel reduced effective cross-linking within the matrix. Without Psl, the matrix becomes more viscous, which facilitates biofilm spreading. The wild-type biofilm decreased in effective cross-linking over time, which would be advantageous for the spreading and colonization of new surfaces. This suggests that there are regulatory mechanisms to control production of the exopolysaccharides that serve to remodel the matrix of developing biofilms. The exopolysaccharides were also found to have profound effects on the spatial organization and integration of P. aeruginosa in a mixed-species biofilm model of P. aeruginosa-Staphylococcus aureus. Pel was required for close association of the two species in mixed-species microcolonies. In contrast, Psl was important for P. aeruginosa to form single-species biofilms on top of S. aureus biofilms. Our results demonstrate that Pel and Psl have distinct physical properties and functional roles during biofilm formation. Importance: Most bacteria grow as biofilms in the environment or in association with eukaryotic hosts. Removal of biofilms that form on surfaces is a challenge in clinical and industrial settings. One of the defining features of a biofilm is its extracellular matrix. The matrix has a heterogeneous structure and is formed from a secretion of various biopolymers, including proteins, extracellular DNA, and polysaccharides. It is generally known to interact with biofilm cells, thus affecting cell physiology and cell-cell communication. Despite the fact that the matrix may comprise up to 90% of the biofilm dry weight, how the matrix properties affect biofilm structure, maturation, and interspecies interactions remain largely unexplored. This study reveals that bacteria can use specific extracellular polymers to modulate the physical properties of their microenvironment. This in turn impacts biofilm structure, differentiation, and interspecies interactions.
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Affiliation(s)
| | - Binu Kundukad
- BioSystems and Micromechanics IRG, Singapore-MIT Alliance for Research and Technology, National University of Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
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Okkotsu Y, Little AS, Schurr MJ. The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes. Front Cell Infect Microbiol 2014; 4:82. [PMID: 24999454 PMCID: PMC4064291 DOI: 10.3389/fcimb.2014.00082] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/02/2014] [Indexed: 01/28/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes a multitude of infections. These infections can occur at almost any site in the body and are usually associated with a breach of the innate immune system. One of the prominent sites where P. aeruginosa causes chronic infections is within the lungs of cystic fibrosis patients. P. aeruginosa uses two-component systems that sense environmental changes to differentially express virulence factors that cause both acute and chronic infections. The P. aeruginosa AlgZR two component system is one of its global regulatory systems that affects the organism's fitness in a broad manner. This two-component system is absolutely required for two P. aeruginosa phenotypes: twitching motility and alginate production, indicating its importance in both chronic and acute infections. Additionally, global transcriptome analyses indicate that it regulates the expression of many different genes, including those associated with quorum sensing, type IV pili, type III secretion system, anaerobic metabolism, cyanide and rhamnolipid production. This review examines the complex AlgZR regulatory network, what is known about the structure and function of each protein, and how it relates to the organism's ability to cause infections.
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Affiliation(s)
- Yuta Okkotsu
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Alexander S Little
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Michael J Schurr
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
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Alhede M, Bjarnsholt T, Givskov M, Alhede M. Pseudomonas aeruginosa biofilms: mechanisms of immune evasion. ADVANCES IN APPLIED MICROBIOLOGY 2014; 86:1-40. [PMID: 24377853 DOI: 10.1016/b978-0-12-800262-9.00001-9] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes (PMNs). In this chapter, the interplay between P. aeruginosa and the PMNs in chronic infections is discussed with focus on the role of rhamnolipids and extracellular DNA.
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Affiliation(s)
- Maria Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.
| | - Thomas Bjarnsholt
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Michael Givskov
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Morten Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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50
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Bartoli C, Berge O, Monteil CL, Guilbaud C, Balestra GM, Varvaro L, Jones C, Dangl JL, Baltrus DA, Sands DC, Morris CE. ThePseudomonas viridiflavaphylogroups in theP. syringaespecies complex are characterized by genetic variability and phenotypic plasticity of pathogenicity-related traits. Environ Microbiol 2014; 16:2301-15. [DOI: 10.1111/1462-2920.12433] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/13/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Claudia Bartoli
- Department of Science and Technology for Agriculture, Forestry, Nature and Energy (DAFNE); Tuscia University; Viterbo Italy
- UR0407 Pathologie Végétale; INRA; Montfavet France
| | - Odile Berge
- UR0407 Pathologie Végétale; INRA; Montfavet France
| | | | | | - Giorgio M. Balestra
- Department of Science and Technology for Agriculture, Forestry, Nature and Energy (DAFNE); Tuscia University; Viterbo Italy
| | - Leonardo Varvaro
- Department of Science and Technology for Agriculture, Forestry, Nature and Energy (DAFNE); Tuscia University; Viterbo Italy
| | - Corbin Jones
- Department of Biology; Carolina Center for Genome Sciences; Chapel Hill NC 29599 USA
| | - Jeffery L. Dangl
- Department of Biology; Howard Hughes Medical Institute; University of North Carolina; Chapel Hill NC 29599 USA
| | - David A. Baltrus
- School of Plant Sciences; University of Arizona; Tucson AZ 85721 USA
| | - David C. Sands
- Department Plant Sciences and Plant Pathology; Montana State University; Bozeman MT 59717-3150 USA
| | - Cindy E. Morris
- UR0407 Pathologie Végétale; INRA; Montfavet France
- Department Plant Sciences and Plant Pathology; Montana State University; Bozeman MT 59717-3150 USA
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