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Wang RZ, Lonergan ZR, Wilbert SA, Eiler JM, Newman DK. Widespread detoxifying NO reductases impart a distinct isotopic fingerprint on N 2O under anoxia. Proc Natl Acad Sci U S A 2024; 121:e2319960121. [PMID: 38865268 PMCID: PMC11194513 DOI: 10.1073/pnas.2319960121] [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: 11/13/2023] [Accepted: 05/10/2024] [Indexed: 06/14/2024] Open
Abstract
Nitrous oxide (N2O), a potent greenhouse gas, can be generated by multiple biological and abiotic processes in diverse contexts. Accurately tracking the dominant sources of N2O has the potential to improve our understanding of N2O fluxes from soils as well as inform the diagnosis of human infections. Isotopic "Site Preference" (SP) values have been used toward this end, as bacterial and fungal nitric oxide reductases (NORs) produce N2O with different isotopic fingerprints, spanning a large range. Here, we show that flavohemoglobin (Fhp), a hitherto biogeochemically neglected yet widely distributed detoxifying bacterial NO reductase, imparts a distinct SP value onto N2O under anoxic conditions (~+10‰) that correlates with typical environmental N2O SP measurements. Using Pseudomonas aeruginosa as a model organism, we generated strains that only contained Fhp or the dissimilatory NOR, finding that in vivo N2O SP values imparted by these enzymes differ by over 10‰. Depending on the cellular physiological state, the ratio of Fhp:NOR varies significantly in wild-type cells and controls the net N2O SP biosignature: When cells grow anaerobically under denitrifying conditions, NOR dominates; when cells experience rapid, increased nitric oxide concentrations under anoxic conditions but are not growing, Fhp dominates. Other bacteria that only make Fhp generate similar N2O SP biosignatures to those measured from our P. aeruginosa Fhp-only strain. Fhp homologs in sequenced bacterial genomes currently exceed NOR homologs by nearly a factor of four. Accordingly, we suggest a different framework to guide the attribution of N2O biological sources in nature and disease.
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Affiliation(s)
- Renée Z. Wang
- Division of Geological and Planetary Sciences, Caltech, Pasadena, CA91101
| | | | - Steven A. Wilbert
- Division of Biology and Biological Engineering, Caltech, Pasadena, CA91101
| | - John M. Eiler
- Division of Geological and Planetary Sciences, Caltech, Pasadena, CA91101
| | - Dianne K. Newman
- Division of Geological and Planetary Sciences, Caltech, Pasadena, CA91101
- Division of Biology and Biological Engineering, Caltech, Pasadena, CA91101
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2
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Shepherd MJ, Fu T, Harrington NE, Kottara A, Cagney K, Chalmers JD, Paterson S, Fothergill JL, Brockhurst MA. Ecological and evolutionary mechanisms driving within-patient emergence of antimicrobial resistance. Nat Rev Microbiol 2024:10.1038/s41579-024-01041-1. [PMID: 38689039 DOI: 10.1038/s41579-024-01041-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2024] [Indexed: 05/02/2024]
Abstract
The ecological and evolutionary mechanisms of antimicrobial resistance (AMR) emergence within patients and how these vary across bacterial infections are poorly understood. Increasingly widespread use of pathogen genome sequencing in the clinic enables a deeper understanding of these processes. In this Review, we explore the clinical evidence to support four major mechanisms of within-patient AMR emergence in bacteria: spontaneous resistance mutations; in situ horizontal gene transfer of resistance genes; selection of pre-existing resistance; and immigration of resistant lineages. Within-patient AMR emergence occurs across a wide range of host niches and bacterial species, but the importance of each mechanism varies between bacterial species and infection sites within the body. We identify potential drivers of such differences and discuss how ecological and evolutionary analysis could be embedded within clinical trials of antimicrobials, which are powerful but underused tools for understanding why these mechanisms vary between pathogens, infections and individuals. Ultimately, improving understanding of how host niche, bacterial species and antibiotic mode of action combine to govern the ecological and evolutionary mechanism of AMR emergence in patients will enable more predictive and personalized diagnosis and antimicrobial therapies.
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Affiliation(s)
- Matthew J Shepherd
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK.
| | - Taoran Fu
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Niamh E Harrington
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Anastasia Kottara
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Kendall Cagney
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - James D Chalmers
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Steve Paterson
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Joanne L Fothergill
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Michael A Brockhurst
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK.
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3
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Wang RZ, Lonergan ZR, Wilbert SA, Eiler JM, Newman DK. Widespread detoxifying NO reductases impart a distinct isotopic fingerprint on N 2O under anoxia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.13.562248. [PMID: 37873075 PMCID: PMC10592819 DOI: 10.1101/2023.10.13.562248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Nitrous oxide (N2O), a potent greenhouse gas, can be generated by compositionally complex microbial populations in diverse contexts. Accurately tracking the dominant biological sources of N2O has the potential to improve our understanding of N2O fluxes from soils as well as inform the diagnosis of human infections. Isotopic "Site Preference" (SP) values have been used towards this end, as bacterial and fungal nitric oxide reductases produce N2O with different isotopic fingerprints. Here we show that flavohemoglobin, a hitherto biogeochemically neglected yet widely distributed detoxifying bacterial NO reductase, imparts a distinct SP value onto N2O under anoxic conditions that correlates with typical environmental N2O SP measurements. We suggest a new framework to guide the attribution of N2O biological sources in nature and disease.
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Affiliation(s)
- Renée Z. Wang
- Division of Geological and Planetary Sciences, Caltech; Pasadena, 91101, USA
| | - Zachery R. Lonergan
- Division of Biology and Biological Engineering, Caltech; Pasadena, 91101, USA
| | - Steven A. Wilbert
- Division of Biology and Biological Engineering, Caltech; Pasadena, 91101, USA
- Current Address: Department of Environmental Health and Engineering, Johns Hopkins; Baltimore, 21218, USA
| | - John M. Eiler
- Division of Geological and Planetary Sciences, Caltech; Pasadena, 91101, USA
| | - Dianne K. Newman
- Division of Geological and Planetary Sciences, Caltech; Pasadena, 91101, USA
- Division of Biology and Biological Engineering, Caltech; Pasadena, 91101, USA
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4
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Lichtenberg M, Kvich L, Larsen SLB, Jakobsen TH, Bjarnsholt T. Inoculum Concentration Influences Pseudomonas aeruginosa Phenotype and Biofilm Architecture. Microbiol Spectr 2022; 10:e0313122. [PMID: 36354337 PMCID: PMC9769529 DOI: 10.1128/spectrum.03131-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/21/2022] [Indexed: 11/12/2022] Open
Abstract
In infections, bacterial cells are often found as relatively small multicellular aggregates characterized by a heterogeneous distribution of phenotype, genotype, and growth rates depending on their surrounding microenvironment. Many laboratory models fail to mimic these characteristics, and experiments are often initiated from planktonic bacteria given optimal conditions for rapid growth without concerns about the microenvironmental characteristics during biofilm maturation. Therefore, we investigated how the initial bacterial concentration (henceforth termed the inoculum) influences the microenvironment during initial growth and how this affects the sizes and distribution of developed aggregates in an embedded biofilm model-the alginate bead biofilm model. Following 24 h of incubation, the viable biomass was independent of starting inoculum but with a radically different microenvironment which led to differences in metabolic activity depending on the inoculum. The inoculum also affected the number of cells surviving treatment with the antibiotic tobramycin, where the highest inoculum showed higher survival rates than the lowest inoculum. The change in antibiotic tolerance was correlated with cell-specific RNA content and O2 consumption rates, suggesting a direct role of metabolic activity. Thus, the starting number of bacteria results in different phenotypic trajectories governed by different microenvironmental characteristics, and we demonstrate some of the possible implications of such physiological gradients on the outcome of in vitro experiments. IMPORTANCE Biofilm aggregates grown in the alginate bead biofilm model bear resemblance to features of in vivo biofilms. Here, we show that changing the initial concentration of bacteria in the biofilm model leads to widely different behavior of the bacteria following an incubation period. This difference is influenced by the local conditions experienced by the bacteria during growth, which impact their response to antibiotic treatment. Our study provides a framework for manipulating aggregate sizes in in vitro biofilm models. It underlines the importance of how experiments are initiated, which can profoundly impact the outcomes and interpretation of microbiological experiments.
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Affiliation(s)
- Mads Lichtenberg
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Lasse Kvich
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Sara Louise Borregaard Larsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Tim Holm Jakobsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Clinical Microbiology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
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5
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Jensen PØ, Nielsen BU, Kolpen M, Pressler T, Faurholt-Jepsen D, Mathiesen IHM. Increased sputum lactate during oral glucose tolerance test in cystic fibrosis. APMIS 2022; 130:535-539. [PMID: 35635299 PMCID: PMC9545947 DOI: 10.1111/apm.13233] [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: 04/28/2022] [Accepted: 05/03/2022] [Indexed: 11/28/2022]
Abstract
Blood glucose levels exceeding 8 mM are shown to increase glucose levels in airway surface in cystic fibrosis (CF). Moreover, high levels of endobronchial glucose are proposed to increase the growth of common CF bacteria and feed the neutrophil‐driven inflammation. In the infected airways, glucose may be metabolized by glycolysis to lactate by both bacteria and neutrophils. Therefore, we aimed to investigate whether increased blood glucose may fuel the glycolytic pathways of the lung inflammation by determining sputum glucose and lactate during an oral glucose tolerance test (OGTT). Sputum from 27 CF patients was collected during an OGTT. Sputum was collected at fasting and one and two hours following the intake of 75 g of glucose. Only participants able to expectorate more than one sputum sample were included. Glucose levels in venous blood and lactate and glucose content in sputum were analyzed using a regular blood gas analyzer. We collected 62 sputum samples: 20 at baseline, 22 after 1 h, and 20 after 2 h. Lactate and glucose were detectable in 30 (48.4%) and 43 (69.4%) sputum samples, respectively. The sputum lactate increased significantly at 2 h in the OGTT (p = 0.024), but sputum glucose was not changed. As expected, plasma glucose level significantly increased during the OGTT (p < 0.001). In CF patients, sputum lactate increased during an OGTT, while the sputum glucose did not reflect the increased plasma glucose. The increase in sputum lactate suggests that glucose spills over from plasma to sputum where glucose may enhance the inflammation by fueling the anaerobic metabolism in neutrophils or bacteria.
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Affiliation(s)
- Peter Østrup Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.,Costerton Biofilm Center, Institute of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Bibi Uhre Nielsen
- Cystic Fibrosis Centre Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Tacjana Pressler
- Cystic Fibrosis Centre Copenhagen, Rigshospitalet, Copenhagen, Denmark
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6
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Lichtenberg M, Jakobsen TH, Kühl M, Kolpen M, Jensen PØ, Bjarnsholt T. OUP accepted manuscript. FEMS Microbiol Rev 2022; 46:6574409. [PMID: 35472245 PMCID: PMC9438473 DOI: 10.1093/femsre/fuac018] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 04/04/2022] [Accepted: 04/24/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mads Lichtenberg
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, København, Denmark
| | - Tim Holm Jakobsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, København, Denmark
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Copenhagen University Hospital, Ole Maaløes vej 26, 2200, København, Denmark
| | - Peter Østrup Jensen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, København, Denmark
- Department of Clinical Microbiology, Copenhagen University Hospital, Ole Maaløes vej 26, 2200, København, Denmark
| | - Thomas Bjarnsholt
- Corresponding author: Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, København, Denmark. Tel: +45 20659888; E-mail:
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7
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Lichtenberg M, Line L, Schrameyer V, Jakobsen TH, Rybtke ML, Toyofuku M, Nomura N, Kolpen M, Tolker-Nielsen T, Kühl M, Bjarnsholt T, Jensen PØ. Nitric-oxide-driven oxygen release in anoxic Pseudomonas aeruginosa. iScience 2021; 24:103404. [PMID: 34849468 PMCID: PMC8608891 DOI: 10.1016/j.isci.2021.103404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/29/2021] [Accepted: 11/03/2021] [Indexed: 11/19/2022] Open
Abstract
Denitrification supports anoxic growth of Pseudomonas aeruginosa in infections. Moreover, denitrification may provide oxygen (O2) resulting from dismutation of the denitrification intermediate nitric oxide (NO) as seen in Methylomirabilis oxyfera. To examine the prevalence of NO dismutation we studied O2 release by P. aeruginosa in airtight vials. P. aeruginosa rapidly depleted O2 but NO supplementation generated peaks of O2 at the onset of anoxia, and we demonstrate a direct role of NO in the O2 release. However, we were not able to detect genetic evidence for putative NO dismutases. The supply of endogenous O2 at the onset of anoxia could play an adaptive role when P. aeruginosa enters anaerobiosis. Furthermore, O2 generation by NO dismutation may be more widespread than indicated by the reports on the distribution of homologues genes. In general, NO dismutation may allow removal of nitrate by denitrification without release of the very potent greenhouse gas, nitrous oxide. Pseudomonas aeruginosa was found to release O2 at the onset of anoxia Peaks of O2 were amplified in a nitric oxide reductase (NOR) mutant The O2 release was mediated by nitric oxide (NO)
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Affiliation(s)
- Mads Lichtenberg
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Laura Line
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Verena Schrameyer
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000 Helsingør, Denmark
| | - Tim Holm Jakobsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Morten Levin Rybtke
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Masanori Toyofuku
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, 305-8577 Tsukuba, Japan
| | - Nobuhiko Nomura
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, 305-8577 Tsukuba, Japan
| | - Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000 Helsingør, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Peter Østrup Jensen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
- Center for Rheumatology and Spine Diseases, Institute for Inflammation Research, Rigshospitalet, 2100 Copenhagen, Denmark
- Corresponding author
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8
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Metabolic reprogramming in chondrocytes to promote mitochondrial respiration reduces downstream features of osteoarthritis. Sci Rep 2021; 11:15131. [PMID: 34302034 PMCID: PMC8302637 DOI: 10.1038/s41598-021-94611-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 07/09/2021] [Indexed: 12/20/2022] Open
Abstract
Metabolic dysfunction in chondrocytes drives the pro-catabolic phenotype associated with osteoarthritic cartilage. In this study, substitution of galactose for glucose in culture media was used to promote a renewed dependence on mitochondrial respiration and oxidative phosphorylation. Galactose replacement alone blocked enhanced usage of the glycolysis pathway by IL1β-activated chondrocytes as detected by real-time changes in the rates of proton acidification of the medium and changes in oxygen consumption. The change in mitochondrial activity due to galactose was visualized as a rescue of mitochondrial membrane potential but not an alteration in the number of mitochondria. Galactose-replacement reversed other markers of dysfunctional mitochondrial metabolism, including blocking the production of reactive oxygen species, nitric oxide, and the synthesis of inducible nitric oxide synthase. Of more clinical relevance, galactose-substitution blocked downstream functional features associated with osteoarthritis, including enhanced levels of MMP13 mRNA, MMP13 protein, and the degradative loss of proteoglycan from intact cartilage explants. Blocking baseline and IL1β-enhanced MMP13 by galactose-replacement in human osteoarthritic chondrocyte cultures inversely paralleled increases in markers associated with mitochondrial recovery, phospho-AMPK, and PGC1α. Comparisons were made between galactose replacement and the glycolysis inhibitor 2-deoxyglucose. Targeting intermediary metabolism may provide a novel approach to osteoarthritis care.
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Cai YM, Zhang YD, Yang L. NO donors and NO delivery methods for controlling biofilms in chronic lung infections. Appl Microbiol Biotechnol 2021; 105:3931-3954. [PMID: 33937932 PMCID: PMC8140970 DOI: 10.1007/s00253-021-11274-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/23/2021] [Accepted: 04/05/2021] [Indexed: 12/18/2022]
Abstract
Nitric oxide (NO), the highly reactive radical gas, provides an attractive strategy in the control of microbial infections. NO not only exhibits bactericidal effect at high concentrations but also prevents bacterial attachment and disperses biofilms at low, nontoxic concentrations, rendering bacteria less tolerant to antibiotic treatment. The endogenously generated NO by airway epithelium in healthy populations significantly contributes to the eradication of invading pathogens. However, this pathway is often compromised in patients suffering from chronic lung infections where biofilms dominate. Thus, exogenous supplementation of NO is suggested to improve the therapeutic outcomes of these infectious diseases. Compared to previous reviews focusing on the mechanism of NO-mediated biofilm inhibition, this review explores the applications of NO for inhibiting biofilms in chronic lung infections. It discusses how abnormal levels of NO in the airways contribute to chronic infections in cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), and primary ciliary dyskinesia (PCD) patients and why exogenous NO can be a promising antibiofilm strategy in clinical settings, as well as current and potential in vivo NO delivery methods. KEY POINTS : • The relationship between abnormal NO levels and biofilm development in lungs • The antibiofilm property of NO and current applications in lungs • Potential NO delivery methods and research directions in the future.
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Affiliation(s)
- Yu-Ming Cai
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Ying-Dan Zhang
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518000, China
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518000, China.
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10
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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: 72] [Impact Index Per Article: 24.0] [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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11
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Urwin L, Okurowska K, Crowther G, Roy S, Garg P, Karunakaran E, MacNeil S, Partridge LJ, Green LR, Monk PN. Corneal Infection Models: Tools to Investigate the Role of Biofilms in Bacterial Keratitis. Cells 2020; 9:E2450. [PMID: 33182687 PMCID: PMC7696224 DOI: 10.3390/cells9112450] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/06/2020] [Accepted: 11/07/2020] [Indexed: 12/15/2022] Open
Abstract
Bacterial keratitis is a corneal infection which may cause visual impairment or even loss of the infected eye. It remains a major cause of blindness in the developing world. Staphylococcus aureus and Pseudomonas aeruginosa are common causative agents and these bacterial species are known to colonise the corneal surface as biofilm populations. Biofilms are complex bacterial communities encased in an extracellular polymeric matrix and are notoriously difficult to eradicate once established. Biofilm bacteria exhibit different phenotypic characteristics from their planktonic counterparts, including an increased resistance to antibiotics and the host immune response. Therefore, understanding the role of biofilms will be essential in the development of new ophthalmic antimicrobials. A brief overview of biofilm-specific resistance mechanisms is provided, but this is a highly multifactorial and rapidly expanding field that warrants further research. Progression in this field is dependent on the development of suitable biofilm models that acknowledge the complexity of the ocular environment. Abiotic models of biofilm formation (where biofilms are studied on non-living surfaces) currently dominate the literature, but co-culture infection models are beginning to emerge. In vitro, ex vivo and in vivo corneal infection models have now been reported which use a variety of different experimental techniques and animal models. In this review, we will discuss existing corneal infection models and their application in the study of biofilms and host-pathogen interactions at the corneal surface.
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Affiliation(s)
- Lucy Urwin
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK; (L.R.G.); (P.N.M.)
| | - Katarzyna Okurowska
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; (K.O.); (G.C.); (E.K.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
| | - Grace Crowther
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; (K.O.); (G.C.); (E.K.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
| | - Sanhita Roy
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad 500034, India; (S.R.); (P.G.)
| | - Prashant Garg
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad 500034, India; (S.R.); (P.G.)
| | - Esther Karunakaran
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; (K.O.); (G.C.); (E.K.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
| | - Sheila MacNeil
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
- Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - Lynda J. Partridge
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Luke R. Green
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK; (L.R.G.); (P.N.M.)
| | - Peter N. Monk
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK; (L.R.G.); (P.N.M.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
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12
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Vo CDT, Michaud J, Elsen S, Faivre B, Bouveret E, Barras F, Fontecave M, Pierrel F, Lombard M, Pelosi L. The O 2-independent pathway of ubiquinone biosynthesis is essential for denitrification in Pseudomonas aeruginosa. J Biol Chem 2020; 295:9021-9032. [PMID: 32409583 PMCID: PMC7335794 DOI: 10.1074/jbc.ra120.013748] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/10/2020] [Indexed: 01/05/2023] Open
Abstract
Many proteobacteria, such as Escherichia coli, contain two main types of quinones: benzoquinones, represented by ubiquinone (UQ) and naphthoquinones, such as menaquinone (MK), and dimethyl-menaquinone (DMK). MK and DMK function predominantly in anaerobic respiratory chains, whereas UQ is the major electron carrier in the reduction of dioxygen. However, this division of labor is probably not very strict. Indeed, a pathway that produces UQ under anaerobic conditions in an UbiU-, UbiV-, and UbiT-dependent manner has been discovered recently in E. coli Its physiological relevance is not yet understood, because MK and DMK are also present in E. coli Here, we established that UQ9 is the major quinone of Pseudomonas aeruginosa and is required for growth under anaerobic respiration (i.e. denitrification). We demonstrate that the ORFs PA3911, PA3912, and PA3913, which are homologs of the E. coli ubiT, ubiV, and ubiU genes, respectively, are essential for UQ9 biosynthesis and, thus, for denitrification in P. aeruginosa These three genes here are called ubiTPa , ubiVPa , and ubiUPa We show that UbiVPa accommodates an iron-sulfur [4Fe-4S] cluster. Moreover, we report that UbiUPa and UbiTPa can bind UQ and that the isoprenoid tail of UQ is the structural determinant required for recognition by these two Ubi proteins. Since the denitrification metabolism of P. aeruginosa is believed to be important for the pathogenicity of this bacterium in individuals with cystic fibrosis, our results highlight that the O2-independent UQ biosynthetic pathway may represent a target for antibiotics development to manage P. aeruginosa infections.
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Affiliation(s)
- Chau-Duy-Tam Vo
- Laboratoire de Chimie des Processus Biologiques, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris, France
| | - Julie Michaud
- CNRS, CHU Grenoble Alpes, Grenoble INP, TIMC-IMAG, Université Grenoble Alpes, Grenoble, France
| | - Sylvie Elsen
- Biology of Cancer and Infection, U1036 INSERM, CEA, Université Grenoble Alpes, ERL5261 CNRS, Grenoble, France
| | - Bruno Faivre
- Laboratoire de Chimie des Processus Biologiques, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris, France
| | - Emmanuelle Bouveret
- SAMe Unit, Department of Microbiology, Institut Pasteur, Paris, France; IMM-UMR 2001 CNRS-Institut Pasteur, Paris, France
| | - Frédéric Barras
- SAMe Unit, Department of Microbiology, Institut Pasteur, Paris, France; IMM-UMR 2001 CNRS-Institut Pasteur, Paris, France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris, France
| | - Fabien Pierrel
- CNRS, CHU Grenoble Alpes, Grenoble INP, TIMC-IMAG, Université Grenoble Alpes, Grenoble, France
| | - Murielle Lombard
- Laboratoire de Chimie des Processus Biologiques, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris, France.
| | - Ludovic Pelosi
- CNRS, CHU Grenoble Alpes, Grenoble INP, TIMC-IMAG, Université Grenoble Alpes, Grenoble, France.
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13
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Jensen P, Møller S, Lerche C, Moser C, Bjarnsholt T, Ciofu O, Faurholt-Jepsen D, Høiby N, Kolpen M. Improving antibiotic treatment of bacterial biofilm by hyperbaric oxygen therapy: Not just hot air. Biofilm 2019; 1:100008. [PMID: 33447795 PMCID: PMC7798444 DOI: 10.1016/j.bioflm.2019.100008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 10/26/2022] Open
Abstract
Bacteria and fungi show substantial increased recalcitrance when growing as infectious biofilms. Chronic infections caused by biofilm growing microorganisms is considered a major problem of modern medicine. New strategies are needed to improve antibiotic treatment of biofilms. We have improved antibiotic treatment of bacterial biofilms by reviving the dormant bacteria and thereby make them susceptible to antibiotics by means of reoxygenation. Here we review the rationale for associating lack of oxygen with low susceptibility in infectious biofilm, and how hyperbaric oxygen therapy may result in reoxygenation leading to enhanced bactericidal activity of antibiotics. We address issues of feasibility and potential adverse effects regarding patient safety and development of resistance. Finally, we propose means for supplying reoxygenation to antibiotic treatment of infectious biofilm with the potential to benefit large groups of patients.
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Affiliation(s)
- P.Ø. Jensen
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200, Copenhagen, Denmark
| | - S.A. Møller
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
| | - C.J. Lerche
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
| | - C. Moser
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
| | - T. Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200, Copenhagen, Denmark
| | - O. Ciofu
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200, Copenhagen, Denmark
| | - D. Faurholt-Jepsen
- Copenhagen Cystic Fibrosis Center, Department of Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK2100, Copenhagen, Denmark
| | - N. Høiby
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200, Copenhagen, Denmark
| | - M. Kolpen
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark
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14
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Conceptual Model of Biofilm Antibiotic Tolerance That Integrates Phenomena of Diffusion, Metabolism, Gene Expression, and Physiology. J Bacteriol 2019; 201:JB.00307-19. [PMID: 31501280 DOI: 10.1128/jb.00307-19] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/28/2019] [Indexed: 01/14/2023] Open
Abstract
Transcriptomic, metabolomic, physiological, and computational modeling approaches were integrated to gain insight into the mechanisms of antibiotic tolerance in an in vitro biofilm system. Pseudomonas aeruginosa biofilms were grown in drip flow reactors on a medium composed to mimic the exudate from a chronic wound. After 4 days, the biofilm was 114 μm thick with 9.45 log10 CFU cm-2 These biofilms exhibited tolerance, relative to exponential-phase planktonic cells, to subsequent treatment with ciprofloxacin. The specific growth rate of the biofilm was estimated via elemental balances to be approximately 0.37 h-1 and with a reaction-diffusion model to be 0.32 h-1, or one-third of the maximum specific growth rate for planktonic cells. Global analysis of gene expression indicated lower transcription of ribosomal genes and genes for other anabolic functions in biofilms than in exponential-phase planktonic cells and revealed the induction of multiple stress responses in biofilm cells, including those associated with growth arrest, zinc limitation, hypoxia, and acyl-homoserine lactone quorum sensing. Metabolic pathways for phenazine biosynthesis and denitrification were transcriptionally activated in biofilms. A customized reaction-diffusion model predicted that steep oxygen concentration gradients will form when these biofilms are thicker than about 40 μm. Mutant strains that were deficient in Psl polysaccharide synthesis, the stringent response, the stationary-phase response, and the membrane stress response exhibited increased ciprofloxacin susceptibility when cultured in biofilms. These results support a sequence of phenomena leading to biofilm antibiotic tolerance, involving oxygen limitation, electron acceptor starvation and growth arrest, induction of associated stress responses, and differentiation into protected cell states.IMPORTANCE Bacteria in biofilms are protected from killing by antibiotics, and this reduced susceptibility contributes to the persistence of infections such as those in the cystic fibrosis lung and chronic wounds. A generalized conceptual model of biofilm antimicrobial tolerance with the following mechanistic steps is proposed: (i) establishment of concentration gradients in metabolic substrates and products; (ii) active biological responses to these changes in the local chemical microenvironment; (iii) entry of biofilm cells into a spectrum of states involving alternative metabolisms, stress responses, slow growth, cessation of growth, or dormancy (all prior to antibiotic treatment); (iv) adaptive responses to antibiotic exposure; and (v) reduced susceptibility of microbial cells to antimicrobial challenges in some of the physiological states accessed through these changes.
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15
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Crabbé A, Jensen PØ, Bjarnsholt T, Coenye T. Antimicrobial Tolerance and Metabolic Adaptations in Microbial Biofilms. Trends Microbiol 2019; 27:850-863. [PMID: 31178124 DOI: 10.1016/j.tim.2019.05.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/25/2019] [Accepted: 05/07/2019] [Indexed: 01/04/2023]
Abstract
Active bacterial metabolism is a prerequisite for optimal activity of many classes of antibiotics. Hence, bacteria have developed strategies to reduce or modulate metabolic pathways to become tolerant. This review describes the tight relationship between metabolism and tolerance in bacterial biofilms, and how physicochemical properties of the microenvironment at the host-pathogen interface (such as oxygen and nutritional content) are key to this relationship. Understanding how metabolic adaptations lead to tolerance brings us to novel approaches to tackle antibiotic-tolerant biofilms. We describe the use of hyperbaric oxygen therapy, metabolism-stimulating metabolites, and alternative strategies to redirect bacterial metabolism towards an antibiotic-susceptible phenotype.
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Affiliation(s)
- Aurélie Crabbé
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Peter Østrup Jensen
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark; Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium.
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16
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Hyperbaric oxygen treatment increases killing of aggregating Pseudomonas aeruginosa isolates from cystic fibrosis patients. J Cyst Fibros 2019; 18:657-664. [PMID: 30711384 DOI: 10.1016/j.jcf.2019.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/10/2019] [Accepted: 01/15/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND Pseudomonas aeruginosa is a major pathogen of the chronic lung infections in cystic fibrosis (CF) patients. These persistent bacterial infections are characterized by bacterial aggregates with biofilm-like properties and are treated with nebulized or intravenous tobramycin in combination with other antibiotics. However, the chronic infections are close to impossible to eradicate due to reasons that are far from fully understood. Recent work has shown that re‑oxygenation of hypoxic aggregates by hyperbaric oxygen (O2) treatment (HBOT: 100% O2 at 2.8 bar) will increase killing of aggregating bacteria by antibiotics. This is relevant for treatment of infected CF patients where bacterial aggregates are found in the endobronchial secretions that are depleted of O2 by the metabolism of polymorphonuclear leukocytes (PMNs). The main objective of this study was to investigate the effect of HBOT as an adjuvant to tobramycin treatment of aggregates formed by P. aeruginosa isolates from CF patients. METHODS The effect was tested using a model with bacterial aggregates embedded in agarose. O2 profiling was used to confirm re‑oxygenation of aggregates. RESULTS We found that HBOT was able to significantly enhance the effect of tobramycin against aggregates of all the P. aeruginosa isolates in vitro. The effect was attributed to increased O2 levels leading to increased growth and thus increased uptake of and killing by tobramycin. CONCLUSIONS Re‑oxygenation may in the future be a clinical possibility as adjuvant to enhance killing by antibiotics in cystic fibrosis lung infections.
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17
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Rossi E, Paroni M, Landini P. Biofilm and motility in response to environmental and host-related signals in Gram negative opportunistic pathogens. J Appl Microbiol 2018; 125:1587-1602. [PMID: 30153375 DOI: 10.1111/jam.14089] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/30/2018] [Accepted: 07/20/2018] [Indexed: 12/13/2022]
Abstract
Most bacteria can switch between a planktonic, sometimes motile, form and a biofilm mode, in which bacterial cells can aggregate and attach to a solid surface. The transition between these two forms represents an example of bacterial adaptation to environmental signals and stresses. In 'environmental pathogens', namely, environmental bacteria that are also able to cause disease in animals and humans, signals associated either with the host or with the external environment, such as temperature, oxygen availability, nutrient concentrations etc., play a major role in triggering the switch between the motile and the biofilm mode, via complex regulatory mechanisms that control flagellar synthesis and motility, and production of adhesion factors. In this review article, we present examples of how environmental signals can impact biofilm formation and cell motility in the Gram negative bacteria Pseudomonas aeruginosa, Escherichia coli and in the Burkholderia genus, and how the switch between motile and biofilm mode can be an essential part of a more general process of adaptation either to the host or to the external environment.
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Affiliation(s)
- E Rossi
- Department of Clinical Microbiology, Rigshospitalet, København, Denmark
| | - M Paroni
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - P Landini
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
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18
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Modelling of ciprofloxacin killing enhanced by hyperbaric oxygen treatment in Pseudomonas aeruginosa PAO1 biofilms. PLoS One 2018; 13:e0198909. [PMID: 29902223 PMCID: PMC6002088 DOI: 10.1371/journal.pone.0198909] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 05/29/2018] [Indexed: 01/12/2023] Open
Abstract
Outline In chronic lung infections by Pseudomonas aeruginosa (PA) the bacteria thrive in biofilm structures protected from the immune system of the host and from antibiotic treatment. Increasing evidence suggests that the susceptibility of the bacteria to antibiotic treatment can be significantly enhanced by hyperbaric oxygen treatment. The aim of this study is to simulate the effect of ciprofloxacin treatment in a PAO1 biofilm model with aggregates in agarose when combined with hyperbaric oxygen treatment. This is achieved in a reaction-diffusion model that describes the combined effect of ciprofloxacin diffusion, oxygen diffusion and depletion, bacterial growth and killing, and adaptation of the bacteria to ciprofloxacin. In the model, the oxygen diffusion and depletion use a set of parameters derived from experimental results presented in this work. The part of the model describing ciprofloxacin killing uses parameter values from the literature in combination with our estimates (Jacobs, et al., 2016; Grillon, et al., 2016). Micro-respirometry experiments were conducted to determine the oxygen consumption in the P. aeruginosa strain PAO1. The parameters were validated against existing data from an HBOT experiment by Kolpen et al. (2017). The complete oxygen model comprises a reaction-diffusion equation describing the oxygen consumption by using a Michaelis-Menten reaction term. The oxygen model performed well in predicting oxygen concentrations in both time and depth into the biofilm. At 2.8 bar pure oxygen pressure, HBOT increases the penetration depth of oxygen into the biofilm almost by a of factor 4 in agreement with the scaling that follows from the stationary balance between the consumption term and diffusion term. Conclusion In the full reaction-diffusion model we see that hyperbaric oxygen treatment significantly increases the killing by ciprofloxacin in a PAO1 biofilm in alignment with the experimental results from Kolpen et al. (Kolpen, et al., 2017; Kolpen, et al. 2016). The enhanced killing, in turn, lowers the oxygen consumption in the outer layers of the biofilm, and leads to even deeper penetration of oxygen into the biofilm.
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19
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Hyperbaric Oxygen Sensitizes Anoxic Pseudomonas aeruginosa Biofilm to Ciprofloxacin. Antimicrob Agents Chemother 2017; 61:AAC.01024-17. [PMID: 28874373 PMCID: PMC5655102 DOI: 10.1128/aac.01024-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/22/2017] [Indexed: 01/08/2023] Open
Abstract
Chronic Pseudomonas aeruginosa lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm, which is subject to strong oxygen (O2) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility of biofilms remain unclear, but accumulating evidence suggests that the efficacy of several bactericidal antibiotics is enhanced by stimulation of aerobic respiration of pathogens, while lack of O2 increases their tolerance. In fact, the bactericidal effect of several antibiotics depends on active aerobic metabolism activity and the endogenous formation of reactive O2 radicals (ROS). In this study, we aimed to apply hyperbaric oxygen treatment (HBOT) to sensitize anoxic P. aeruginosa agarose biofilms established to mimic situations with intense O2 consumption by the host response in the cystic fibrosis (CF) lung. Application of HBOT resulted in enhanced bactericidal activity of ciprofloxacin at clinically relevant durations and was accompanied by indications of restored aerobic respiration, involvement of endogenous lethal oxidative stress, and increased bacterial growth. The findings highlight that oxygenation by HBOT improves the bactericidal activity of ciprofloxacin on P. aeruginosa biofilm and suggest that bacterial biofilms are sensitized to antibiotics by supplying hyperbaric O2.
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20
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Gottrup F, Dissemond J, Baines C, Frykberg R, Jensen PØ, Kot J, Kröger K, Longobardi P. Use of Oxygen Therapies in Wound Healing. J Wound Care 2017; 26:S1-S43. [DOI: 10.12968/jowc.2017.26.sup5.s1] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Finn Gottrup
- University of Southern Denmark, Copenhagen Wound Healing Center, Department of Dermatology, D42, Bispebjerg University Hospital, DK-2400 Copenhagen NV, Denmark
| | - Joachim Dissemond
- Department of Dermatology, Venerology and Allergology, University Hospital of Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Carol Baines
- Royal Hobart Hospital, Hobart, Tasmania, Australia
| | - Robert Frykberg
- University of Arizona College of Medicine-Phoenix, AZ 85012 Phoenix, Arizona, USA
| | - Peter Østrup Jensen
- Department of Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Denmark and Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Jacek Kot
- National Center for Hyperbaric Medicine, Medical University of Gdansk, Powstania Styczniowego Str. 9B, 81-519 Gdynia, Poland
| | - Knut Kröger
- Department of Vascular Medicine, HELIOS Klinikum Krefeld, 47805 Krefeld, Germany
| | - Pasquale Longobardi
- Affiliate Researcher Institute for Life Sciences, Scuola Superiore Sant'Anna (SSSA) Pisa, Italy Medical Director Centro iperbarico, Ravenna, Italy
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21
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Moser C, Pedersen HT, Lerche CJ, Kolpen M, Line L, Thomsen K, Høiby N, Jensen PØ. Biofilms and host response - helpful or harmful. APMIS 2017; 125:320-338. [PMID: 28407429 DOI: 10.1111/apm.12674] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 01/14/2017] [Indexed: 01/09/2023]
Abstract
Biofilm infections are one of the modern medical world's greatest challenges. Probably, all non-obligate intracellular bacteria and fungi can establish biofilms. In addition, there are numerous biofilm-related infections, both foreign body-related and non-foreign body-related. Although biofilm infections can present in numerous ways, one common feature is involvement of the host response with significant impact on the course. A special characteristic is the synergy of the innate and the acquired immune responses for the induced pathology. Here, we review the impact of the host response for the course of biofilm infections, with special focus on cystic fibrosis, chronic wounds and infective endocarditis.
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Affiliation(s)
- Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Hannah Trøstrup Pedersen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Christian Johann Lerche
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Costerton Biofilm Center, Institute of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Laura Line
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Kim Thomsen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Costerton Biofilm Center, Institute of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Costerton Biofilm Center, Institute of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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22
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Jensen PØ, Kolpen M, Kragh KN, Kühl M. Microenvironmental characteristics and physiology of biofilms in chronic infections of CF patients are strongly affected by the host immune response. APMIS 2017; 125:276-288. [PMID: 28407427 DOI: 10.1111/apm.12668] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 01/04/2017] [Indexed: 01/14/2023]
Abstract
In vitro studies of Pseudomonas aeruginosa and other pathogenic bacteria in biofilm aggregates have yielded detailed insight into their potential growth modes and metabolic flexibility under exposure to gradients of substrate and electron acceptor. However, the growth pattern of P. aeruginosa in chronic lung infections of cystic fibrosis (CF) patients is very different from what is observed in vitro, for example, in biofilms grown in flow chambers. Dense in vitro biofilms of P. aeruginosa exhibit rapid O2 depletion within <50-100 μm due to their own aerobic metabolism. In contrast, in vivo investigations show that P. aeruginosa persists in the chronically infected CF lung as relatively small cell aggregates that are surrounded by numerous PMNs, where the activity of PMNs is the major cause of O2 depletion rendering the P. aeruginosa aggregates anoxic. High levels of nitrate and nitrite enable P. aeruginosa to persist fueled by denitrification in the PMN-surrounded biofilm aggregates. This configuration creates a potentially long-term stable ecological niche for P. aeruginosa in the CF lung, which is largely governed by slow growth and anaerobic metabolism and enables persistence and resilience of this pathogen even under the recurring aggressive antimicrobial treatments of CF patients. As similar slow growth of other CF pathogens has recently been observed in endobronchial secretions, there is now a clear need for better in vitro models that simulate such in vivo growth patterns and anoxic microenvironments in order to help unravel the efficiency of existing or new antimicrobials targeting anaerobic metabolism in P. aeruginosa and other CF pathogens. We also advocate that host immune responses such as PMN-driven O2 depletion play a central role in the formation of anoxic microniches governing bacterial persistence in other chronic infections such as chronic wounds.
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Affiliation(s)
- Peter Ø Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.,Department of International Health, Immunology and Microbiology, UC-CARE, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.,Department of International Health, Immunology and Microbiology, UC-CARE, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kasper N Kragh
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.,Department of International Health, Immunology and Microbiology, UC-CARE, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.,Climate Change Cluster, University of Technology, Sydney, NSW, Australia
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23
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Robinson JL, Jaslove JM, Murawski AM, Fazen CH, Brynildsen MP. An integrated network analysis reveals that nitric oxide reductase prevents metabolic cycling of nitric oxide by Pseudomonas aeruginosa. Metab Eng 2017; 41:67-81. [PMID: 28363762 DOI: 10.1016/j.ymben.2017.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/21/2016] [Accepted: 03/27/2017] [Indexed: 01/08/2023]
Abstract
Nitric oxide (NO) is a chemical weapon within the arsenal of immune cells, but is also generated endogenously by different bacteria. Pseudomonas aeruginosa are pathogens that contain an NO-generating nitrite (NO2-) reductase (NirS), and NO has been shown to influence their virulence. Interestingly, P. aeruginosa also contain NO dioxygenase (Fhp) and nitrate (NO3-) reductases, which together with NirS provide the potential for NO to be metabolically cycled (NO→NO3-→NO2-→NO). Deeper understanding of NO metabolism in P. aeruginosa will increase knowledge of its pathogenesis, and computational models have proven to be useful tools for the quantitative dissection of NO biochemical networks. Here we developed such a model for P. aeruginosa and confirmed its predictive accuracy with measurements of NO, O2, NO2-, and NO3- in mutant cultures devoid of Fhp or NorCB (NO reductase) activity. Using the model, we assessed whether NO was metabolically cycled in aerobic P. aeruginosa cultures. Calculated fluxes indicated a bottleneck at NO3-, which was relieved upon O2 depletion. As cell growth depleted dissolved O2 levels, NO3- was converted to NO2- at near-stoichiometric levels, whereas NO2- consumption did not coincide with NO or NO3- accumulation. Assimilatory NO2- reductase (NirBD) or NorCB activity could have prevented NO cycling, and experiments with ΔnirB, ΔnirS, and ΔnorC showed that NorCB was responsible for loss of flux from the cycle. Collectively, this work provides a computational tool to analyze NO metabolism in P. aeruginosa, and establishes that P. aeruginosa use NorCB to prevent metabolic cycling of NO.
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Affiliation(s)
- Jonathan L Robinson
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jacob M Jaslove
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Rutgers Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Allison M Murawski
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Rutgers Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Christopher H Fazen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Mark P Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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24
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Erukainure OL, Zaruwa MZ, Mesaik AM, Muhammad A, Adoga JO, Ogunyemi IO, Ebuehi OA, Elemo GN. Suppression of phagocytic oxidative burst, cytotoxic effect, and computational prediction of oral toxicity of dietary fatty acids of Clerodendrum volubile stem. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s00580-017-2438-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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25
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Lin CK, Kazmierczak BI. Inflammation: A Double-Edged Sword in the Response to Pseudomonas aeruginosa Infection. J Innate Immun 2017; 9:250-261. [PMID: 28222444 DOI: 10.1159/000455857] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/05/2017] [Indexed: 12/22/2022] Open
Abstract
The Gram-negative opportunistic pathogen Pseudomonas aeruginosa exploits failures of barrier defense and innate immunity to cause acute infections at a range of anatomic sites. We review the defense mechanisms that normally protect against P. aeruginosa pulmonary infection, as well as the bacterial products and activities that trigger their activation. Innate immune recognition of P. aeruginosa is critical for pathogen clearance; nonetheless, inflammation is also associated with pathogen persistence and poor host outcomes. We describe P. aeruginosa adaptations that improve this pathogen's fitness in the inflamed airway, and briefly discuss strategies to manipulate inflammation to benefit the host. Such adjunct therapies may become increasingly important in the treatment of acute and chronic infections caused by this multi-drug-resistant pathogen.
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Whether a novel drug delivery system can overcome the problem of biofilms in respiratory diseases? Drug Deliv Transl Res 2016; 7:179-187. [DOI: 10.1007/s13346-016-0349-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Flowers of Clerodendrum volubile exacerbate immunomodulation by suppressing phagocytic oxidative burst and modulation of COX-2 activity. Biomed Pharmacother 2016; 83:1478-1484. [DOI: 10.1016/j.biopha.2016.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/22/2016] [Accepted: 09/01/2016] [Indexed: 01/13/2023] Open
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Scales BS, Dickson RP, Huffnagle GB. A tale of two sites: how inflammation can reshape the microbiomes of the gut and lungs. J Leukoc Biol 2016; 100:943-950. [PMID: 27365534 DOI: 10.1189/jlb.3mr0316-106r] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/06/2016] [Indexed: 12/31/2022] Open
Abstract
Inflammation can directly and indirectly modulate the bacterial composition of the microbiome. Although studies of inflammation primarily focus on its function to negatively select against potential pathogens, some bacterial species have the ability to exploit inflammatory byproducts for their benefit. Inflammatory cells release reactive nitrogen species as antimicrobial effectors against infection, but some facultative anaerobes can also utilize the increase in extracellular nitrate in their environment for anaerobic respiration and growth. This phenomenon has been studied in the gastrointestinal tract, where blooms of facultative anaerobic Gammaproteobacteria, primarily Escherichia coli, often occur during colonic inflammation. In cystic fibrosis, Pseudomonas aeruginosa, another Gammaproteobacteria facultative anaerobe, can reduce nitrogen for anaerobic respiration and it blooms in the airways of the chronically inflamed cystic fibrosis lung. This review focuses on the evidence that inflammation can provide terminal electron acceptors for anaerobic respiration and can support blooms of facultative anaerobes, such as E. coli and P. aeruginosa in distinct, but similar, environments of the inflamed gastrointestinal and respiratory tracts.
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Affiliation(s)
- Brittan S Scales
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Robert P Dickson
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Gary B Huffnagle
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Désert C, Merlot E, Zerjal T, Bed'hom B, Härtle S, Le Cam A, Roux PF, Baeza E, Gondret F, Duclos MJ, Lagarrigue S. Transcriptomes of whole blood and PBMC in chickens. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2016; 20:1-9. [PMID: 27442111 DOI: 10.1016/j.cbd.2016.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 05/16/2016] [Accepted: 06/22/2016] [Indexed: 10/21/2022]
Abstract
Global transcriptome analysis of chicken whole blood to discover biomarkers of different phenotypes or physiological disorders has never been investigated so far. Whole blood provides significant advantages, allowing large scale and non-invasive sampling. However, generation of gene expression data from the blood of non-mammalian species remains a challenge, notably due to the nucleated red blood cells, hindering the use of well-established protocols. The aim of this study was to analyze the relevance of using whole blood cells (WB) to find biomarkers, instead of Peripheral Blood Mononuclear Cells (PBMC), usually chosen for immune challenges. RNA sources from WB and PBMC was characterized by microarray analysis. Our results show that the quality and quantity of RNA obtained from WB was suitable for further analyses, although the quality was lower than that from PBMC. The transcriptome profiling comparison revealed that the majority of genes were expressed in both WB and PBMC. Hemoglobin subunits were the major transcripts in WB, whereas the most enriched biological process was related to protein catabolic process. Most of the over-represented transcripts in PBMC were implicated in functions specific to thrombocytes, like coagulation and platelet activation, probably due to the large proportion of this nucleated cell type in chicken PBMC. Functions related to B and T cells and to other immune functions were also enriched in the PBMC subset. We conclude that WB is more suitable for large scale immunity oriented studies and other biological processes that have been poorly investigated so far.
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Affiliation(s)
- Colette Désert
- INRA, UMR1348 Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'élevage, Saint-Gilles, France; Agrocampus-Ouest, UMR1348, Rennes, France.
| | - Elodie Merlot
- INRA, UMR1348 Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'élevage, Saint-Gilles, France; Agrocampus-Ouest, UMR1348, Rennes, France
| | - Tatiana Zerjal
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Bertrand Bed'hom
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Sonja Härtle
- Department of Veterinary Sciences, Ludwig Maximilian University, Munich, Germany
| | - Aurélie Le Cam
- INRA, UR1037 Laboratoire de Physiologie et Génomique des Poissons, Rennes, France
| | - Pierre-François Roux
- INRA, UMR1348 Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'élevage, Saint-Gilles, France; Agrocampus-Ouest, UMR1348, Rennes, France
| | | | - Florence Gondret
- INRA, UMR1348 Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'élevage, Saint-Gilles, France; Agrocampus-Ouest, UMR1348, Rennes, France
| | | | - Sandrine Lagarrigue
- INRA, UMR1348 Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'élevage, Saint-Gilles, France; Agrocampus-Ouest, UMR1348, Rennes, France
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Kolpen M, Mousavi N, Sams T, Bjarnsholt T, Ciofu O, Moser C, Kühl M, Høiby N, Jensen PØ. Reinforcement of the bactericidal effect of ciprofloxacin on Pseudomonas aeruginosa biofilm by hyperbaric oxygen treatment. Int J Antimicrob Agents 2016; 47:163-7. [DOI: 10.1016/j.ijantimicag.2015.12.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/03/2015] [Accepted: 12/09/2015] [Indexed: 02/07/2023]
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Kolpen M, Appeldorff CF, Brandt S, Mousavi N, Kragh KN, Aydogan S, Uppal HA, Bjarnsholt T, Ciofu O, Høiby N, Jensen PØ. Increased bactericidal activity of colistin on Pseudomonas aeruginosa biofilms in anaerobic conditions. Pathog Dis 2015; 74:ftv086. [PMID: 26458402 PMCID: PMC4655427 DOI: 10.1093/femspd/ftv086] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2015] [Indexed: 12/19/2022] Open
Abstract
Tolerance towards antibiotics of Pseudomonas aeruginosa biofilms is recognized as a major cause of therapeutic failure of chronic lung infection in cystic fibrosis (CF) patients. This lung infection is characterized by antibiotic-tolerant biofilms in mucus with zones of O2 depletion mainly due to polymorphonuclear leukocytic activity. In contrast to the main types of bactericidal antibiotics, it has not been possible to establish an association between the bactericidal effects of colistin and the production of detectable levels of OH ˙ on several strains of planktonic P. aeruginosa. Therefore, we propose that production of OH ˙ may not contribute significantly to the bactericidal activity of colistin on P. aeruginosa biofilm. Thus, we investigated the effect of colistin treatment on biofilm of wild-type PAO1, a catalase-deficient mutant (ΔkatA) and a colistin-resistant CF isolate cultured in microtiter plates in normoxic- or anoxic atmosphere with 1 mM nitrate. The killing of bacteria during colistin treatment was measured by CFU counts, and the OH⋅ formation was measured by 3(')-(p-hydroxylphenyl fluorescein) fluorescein (HPF) fluorescence. Validation of the assay was done by hydrogen peroxide treatment. OH⋅ formation was undetectable in aerobic PAO1 biofilms during 3 h of colistin treatment. Interestingly, we demonstrate increased susceptibility of P. aeruginosa biofilms towards colistin during anaerobic conditions. In fact, the maximum enhancement of killing by anaerobic conditions exceeded 2 logs using 4 mg L(-1) of colistin compared to killing at aerobic conditions.
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Affiliation(s)
- Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark Department of Immunology and Microbiology, UC-CARE, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | | | - Sarah Brandt
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Nabi Mousavi
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Kasper N Kragh
- Department of Immunology and Microbiology, UC-CARE, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Sevtap Aydogan
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Haleema A Uppal
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark Department of Immunology and Microbiology, UC-CARE, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Oana Ciofu
- Department of Immunology and Microbiology, UC-CARE, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark Department of Immunology and Microbiology, UC-CARE, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Peter Ø Jensen
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
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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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López-Causapé C, Rojo-Molinero E, Macià MD, Oliver A. The problems of antibiotic resistance in cystic fibrosis and solutions. Expert Rev Respir Med 2014; 9:73-88. [PMID: 25541089 DOI: 10.1586/17476348.2015.995640] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chronic respiratory infection is the main cause of morbidity and mortality in cystic fibrosis (CF) patients. One of the hallmarks of these infections, led by the opportunistic pathogen Pseudomonas aeruginosa, is their long-term (lifelong) persistence despite intensive antimicrobial therapy. Antimicrobial resistance in CF is indeed a multifactorial problem, which includes physiological changes, represented by the transition from the planktonic to the biofilm mode of growth and the acquisition of multiple (antibiotic resistance) adaptive mutations catalyzed by frequent mutator phenotypes. Emerging multidrug-resistant CF pathogens, transmissible epidemic strains and transferable genetic elements (such as those encoding class B carbapenemases) also significantly contribute to this concerning scenario. Strategies directed to combat biofilm growth, prevent the emergence of mutational resistance, promote the development of novel antimicrobial agents against multidrug-resistant strains and implement strict infection control measures are thus needed.
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Affiliation(s)
- Carla López-Causapé
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria de Palma (IdISPa), Ctra. Valldemossa 79, 07010 Palma de Mallorca, Spain
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Line L, Alhede M, Kolpen M, Kühl M, Ciofu O, Bjarnsholt T, Moser C, Toyofuku M, Nomura N, Høiby N, Jensen PØ. Physiological levels of nitrate support anoxic growth by denitrification of Pseudomonas aeruginosa at growth rates reported in cystic fibrosis lungs and sputum. Front Microbiol 2014; 5:554. [PMID: 25386171 PMCID: PMC4208399 DOI: 10.3389/fmicb.2014.00554] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 10/03/2014] [Indexed: 12/13/2022] Open
Abstract
Chronic Pseudomonas aeruginosa lung infection is the most severe complication in patients with cystic fibrosis (CF). The infection is characterized by the formation of biofilm surrounded by numerous polymorphonuclear leukocytes (PMNs) and strong O2 depletion in the endobronchial mucus. We have reported that O2 is mainly consumed by the activated PMNs, while O2 consumption by aerobic respiration is diminutive and nitrous oxide (N2O) is produced in infected CF sputum. This suggests that the reported growth rates of P. aeruginosa in lungs and sputum may result from anaerobic respiration using denitrification. The growth rate of P. aeruginosa achieved by denitrification at physiological levels (~400 μM) of nitrate (NO(-) 3) is however, not known. Therefore, we have measured growth rates of anoxic cultures of PAO1 and clinical isolates (n = 12) in LB media supplemented with NO(-) 3 and found a significant increase of growth when supplementing PAO1 and clinical isolates with ≥150 μM NO(-) 3 and 100 μM NO(-) 3, respectively. An essential contribution to growth by denitrification was demonstrated by the inability to establish a significantly increased growth rate by a denitrification deficient ΔnirS-N mutant at <1 mM of NO(-) 3. Activation of denitrification could be achieved by supplementation with as little as 62.5 μM of NO(-) 3 according to the significant production of N2O by the nitrous oxide reductase deficient ΔnosZ mutant. Studies of the promoter activity, gene transcripts, and enzyme activity of the four N-oxide reductases in PAO1 (Nar, Nir, Nor, Nos) further verified the engagement of denitrification, showing a transient increase in activation and expression and rapid consumption of NO(-) 3 followed by a transient increase of NO(-) 2. Growth rates obtained by denitrification in this study were comparable to our reported growth rates in the majority of P. aeruginosa cells in CF lungs and sputum. Thus, we have demonstrated that denitrification is required for P. aeruginosa growth in infected endobronchial CF mucus.
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Affiliation(s)
- Laura Line
- Department of Clinical Microbiology Rigshospitalet, Copenhagen, Denmark ; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen Copenhagen, Denmark
| | - Morten Alhede
- Department of Clinical Microbiology Rigshospitalet, Copenhagen, Denmark ; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology Rigshospitalet, Copenhagen, Denmark ; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen Copenhagen, Denmark
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen Copenhagen, Denmark ; Plant Functional Biology and Climate Change Cluster, University of Technology Sydney Sydney, NSW, Australia ; Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University Singapore, Singapore
| | - Oana Ciofu
- Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Department of Clinical Microbiology Rigshospitalet, Copenhagen, Denmark ; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology Rigshospitalet, Copenhagen, Denmark
| | - Masanori Toyofuku
- Graduate School of Life and Environmental Sciences, University of Tsukuba Tsukuba, Japan
| | - Nobuhiko Nomura
- Graduate School of Life and Environmental Sciences, University of Tsukuba Tsukuba, Japan
| | - Niels Høiby
- Department of Clinical Microbiology Rigshospitalet, Copenhagen, Denmark ; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen Copenhagen, Denmark
| | - Peter Ø Jensen
- Department of Clinical Microbiology Rigshospitalet, Copenhagen, Denmark
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Kolpen M, Kragh KN, Bjarnsholt T, Line L, Hansen CR, Dalbøge CS, Hansen N, Kühl M, Høiby N, Jensen PØ. Denitrification by cystic fibrosis pathogens - Stenotrophomonas maltophilia is dormant in sputum. Int J Med Microbiol 2014; 305:1-10. [PMID: 25441256 DOI: 10.1016/j.ijmm.2014.07.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 07/03/2014] [Accepted: 07/15/2014] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Chronic Pseudomonas aeruginosa lung infection is the most severe complication for cystic fibrosis (CF) patients. Infected endobronchial mucus of CF patients contains anaerobic zones mainly due to the respiratory burst of polymorphonuclear leukocytes. We have recently demonstrated ongoing denitrification in sputum from patients infected with P. aeruginosa. Therefore we aimed to investigate, whether the pathogenicity of several known CF pathogens is correlated to their ability to perform denitrification. METHODS We measured denitrification with N(2)O microsensors in concert with anaerobic growth measurements by absorbance changes and colony counting in isolates from 32 CF patients chronically infected with the highly pathogenic bacteria P. aeruginosa, Achromobacter xylosoxidans, Burkholderia multivorans or the less pathogenic bacterium Stenotrophomonas maltophilia. Consumption of NO(3)(-) and NO(2)(-) was estimated by the Griess Assay. All isolates were assayed during 2 days of incubation in anaerobic LB broth with NO(3)(-) or NO(2)(-). PNA FISH staining of 16S rRNA was used to estimate the amount of ribosomes per bacterial cells and thereby the in situ growth rate of S. maltophilia in sputum. RESULTS Supplemental NO(3)(-) caused increased production of N(2)O by P. aeruginosa, A. xylosoxidans and B. multivorans and increased growth for all pathogens. Growth was, however, lowest for S. maltophilia. NO(3)(-) was metabolized by all pathogens, but only P. aeruginosa was able to remove NO(2)(-). S. maltophilia had limited growth in sputum as seen by the weak PNA FISH staining. CONCLUSIONS All four pathogens were able to grow anaerobically by NO(3)(-) reduction. Denitrification as demonstrated by N(2)O production was, however, not found in S. maltophilia isolates. The ability to perform denitrification may contribute to the pathogenicity of the infectious isolates since complete denitrification promotes faster anaerobic growth. The inability of S. maltophilia to proliferate by denitrification and therefore grow in the anaerobic CF sputum may explain its low pathogenicity in CF patients.
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Affiliation(s)
- Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kasper Nørskov Kragh
- Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Laura Line
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Christine Rønne Hansen
- Department of Paediatrics, Copenhagen CF Centre, Rigshospitalet, 2100 Copenhagen, Denmark
| | | | - Nana Hansen
- Department of Veterinary Disease Biology, Veterinary Clinical Microbiology, University of Copenhagen, 1870 Frederiksberg, Denmark
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000 Helsingør, Denmark; Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, Australia; Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark; Department of International Health, Immunology and Microbiology, Faculty of Health Sciences University of Copenhagen, 2200 Copenhagen, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Rigshospitalet, 2100 Copenhagen, Denmark.
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McDermott AJ, Frank CR, Falkowski NR, McDonald RA, Young VB, Huffnagle GB. Role of GM-CSF in the inflammatory cytokine network that regulates neutrophil influx into the colonic mucosa during Clostridium difficile infection in mice. Gut Microbes 2014; 5:476-84. [PMID: 25045999 PMCID: PMC5915364 DOI: 10.4161/gmic.29964] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Clostridium difficile infection in antibiotic-treated mice results in acute colitis characterized by severe intestinal histopathology, robust neutrophil influx, and increased expression of numerous inflammatory cytokines, including GM-CSF. We utilized a neutralizing monoclonal antibody (mAb) against GM-CSF in a murine model to study the role of GM-CSF during acute C. difficile colitis. Cefoperazone-treated mice were challenged with C. difficile (strain 630) spores. Expression of GM-CSF was significantly increased in animals challenged with C. difficile. Treatment with an anti-GM-CSF mAb did not alter C. difficile colonization levels, weight loss, or expression of IL-22 and RegIIIγ. However, expression of the inflammatory cytokines TNFα and IL-1β, as well as iNOS, was significantly reduced following anti-GM-CSF treatment. Expression of the neutrophil chemokines CXCL1 and CXCL2, but not the chemokines CCL2, CCL4, CXCL9, and CXCL10, was significantly reduced by anti-GM-CSF treatment. Consistent with a decrease in neutrophil-attractant chemokine expression, there were fewer neutrophils in histology sections and a reduction in the expression of secretory leukocyte protease inhibitor (SLPI), a tissue anti-protease that protects against damage by secreted neutrophil elastase. These data indicate that GM-CSF plays a role in the inflammatory signaling network that drives neutrophil recruitment in response to C. difficile infection but does not appear to play a role in clearance of the infection.
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Affiliation(s)
- Andrew J McDermott
- Department of Microbiology and Immunology; University of Michigan Medical School; Ann Arbor, MI USA
| | - Charles R Frank
- Division of Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Michigan Medical School; Ann Arbor, MI USA
| | - Nicole R Falkowski
- Division of Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Michigan Medical School; Ann Arbor, MI USA
| | - Roderick A McDonald
- Division of Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Michigan Medical School; Ann Arbor, MI USA
| | - Vincent B Young
- Department of Microbiology and Immunology; University of Michigan Medical School; Ann Arbor, MI USA,Division of Infectious Diseases; Department of Internal Medicine; University of Michigan Medical School; Ann Arbor, MI USA
| | - Gary B Huffnagle
- Department of Microbiology and Immunology; University of Michigan Medical School; Ann Arbor, MI USA,Division of Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Michigan Medical School; Ann Arbor, MI USA,Correspondence to: Gary B Huffnagle;
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