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Hofstaedter CE, Chandler CE, Met CM, Gillespie JJ, Harro JM, Goodlett DR, Rasko DA, Ernst RK. Divergent Pseudomonas aeruginosa LpxO enzymes perform site-specific lipid A 2-hydroxylation. mBio 2024; 15:e0282323. [PMID: 38131669 PMCID: PMC10865791 DOI: 10.1128/mbio.02823-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Pseudomonas aeruginosa can survive in a myriad of environments, partially due to modifications of its lipid A, the membrane anchor of lipopolysaccharide. We previously demonstrated that divergent late acyltransferase paralogs, HtrB1 and HtrB2, add acyloxyacyl laurate to lipid A 2- and 2'-acyl chains, respectively. The genome of P. aeruginosa also has genes which encode two dioxygenase enzymes, LpxO1 and LpxO2, that individually hydroxylate a specific secondary laurate. LpxO1 acts on the 2'-acyloxyacyl laurate (added by HtrB2), whereas LpxO2 acts on the 2-acyloxyacyl laurate (added by HtrB1) in a site-specific manner. Furthermore, while both enzyme pairs are evolutionarily linked, phylogenomic analysis suggests the LpxO1/HtrB2 enzyme pair as being of ancestral origin, present throughout the Pseudomonas lineage, whereas the LpxO2/HtrB1 enzyme pair likely arose via horizontal gene transfer and has been retained in P. aeruginosa over time. Using a murine pulmonary infection model, we showed that both LpxO1 and LpxO2 enzymes are functional in vivo, as direct analysis of in vivo lipid A structure from bronchoalveolar lavage fluid revealed 2-hydroxylated lipid A. Gene expression analysis reveals increased lpxO2 but unchanged lpxO1 expression in vivo, suggesting differential regulation of these enzymes during infection. We also demonstrate that loss-of-function mutations arise in lpxO1 and lpxO2 during chronic lung infection in people with cystic fibrosis (CF), indicating a potential role for pathogenesis and airway adaptation. Collectively, our study characterizes lipid A 2-hydroxylation during P. aeruginosa airway infection that is regulated by two distinct lipid A dioxygenase enzymes.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen that causes severe infection in hospitalized and chronically ill individuals. During infection, P. aeruginosa undergoes adaptive changes to evade host defenses and therapeutic interventions, increasing mortality and morbidity. Lipid A structural alteration is one such change that P. aeruginosa isolates undergo during chronic lung infection in CF. Investigating genetic drivers of this lipid A structural variation is crucial in understanding P. aeruginosa adaptation during infection. Here, we describe two lipid A dioxygenases with acyl-chain site specificity, each with different evolutionary origins. Further, we show that loss of function in these enzymes occurs in CF clinical isolates, suggesting a potential pathoadaptive phenotype. Studying these bacterial adaptations provides insight into selection pressures of the CF airway on P. aeruginosa phenotypes that persist during chronic infection. Understanding these adaptive changes may ultimately provide clinicians better control over bacterial populations during chronic infection.
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Affiliation(s)
- Casey E. Hofstaedter
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, Maryland, USA
- Medical Scientist Training Program, University of Maryland, Baltimore, Baltimore, Maryland, USA
| | - Courtney E. Chandler
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, Maryland, USA
| | - Charles M. Met
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, Maryland, USA
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, University of Maryland Baltimore, Baltimore, Maryland, USA
| | - Janette M. Harro
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, Maryland, USA
| | - David R. Goodlett
- Departments of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - David A. Rasko
- Department of Microbiology and Immunology, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute for Genome Sciences, University of Maryland, Baltimore, Baltimore, Maryland, USA
- Center for Pathogen Research, University of Maryland, Baltimore, Baltimore, Maryland, USA
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland Baltimore, Baltimore, Maryland, USA
- Center for Pathogen Research, University of Maryland, Baltimore, Baltimore, Maryland, USA
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Mandal P, Lyons JD, Burd EM, Koval M, Mocarski ES, Coopersmith CM. Integrated evaluation of lung disease in single animals. PLoS One 2021; 16:e0246270. [PMID: 34237078 PMCID: PMC8266100 DOI: 10.1371/journal.pone.0246270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 01/15/2021] [Indexed: 11/18/2022] Open
Abstract
During infectious disease, pathogen load drives inflammation and immune response that together contribute to tissue injury often resulting in organ dysfunction. Pulmonary failure in SARS-CoV2-infected hospitalized COVID-19 patients is one such prominent example. Intervention strategies require characterization of the host-pathogen interaction by accurately assessing all of the above-mentioned disease parameters. To study infection in intact mammals, mice are often used as essential genetic models. Due to humane concerns, there is a constant unmet demand to develop studies that reduce the number of mice utilized while generating objective data. Here, we describe an integrated method of evaluating lung inflammation in mice infected with Pseudomonas aeruginosa or murine gammaherpesvirus (MHV)-68. This method conserves animal resources while permitting evaluation of disease mechanisms in both infection settings. Lungs from a single euthanized mouse were used for two purposes-biological assays to determine inflammation and infection load, as well as histology to evaluate tissue architecture. For this concurrent assessment of multiple parameters from a single euthanized mouse, we limit in-situ formalin fixation to the right lung of the cadaver. The unfixed left lung is collected immediately and divided into several segments for biological assays including determination of pathogen titer, assessment of infection-driven cytokine levels and appearance of cell death markers. In situ fixed right lung was then processed for histological determination of tissue injury and confirmation of infection-driven cell death patterns. This method reduces overall animal use and minimizes inter-animal variability that results from sacrificing different animals for different types of assays. The technique can be applied to any lung disease study in mice or other mammals.
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Affiliation(s)
- Pratyusha Mandal
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, United States of America
| | - John D. Lyons
- Department of Surgery, Emory Critical Care Center, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Eileen M. Burd
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine and Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Edward S. Mocarski
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Craig M. Coopersmith
- Department of Surgery, Emory Critical Care Center, Emory University School of Medicine, Atlanta, GA, United States of America
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Bobrov AG, Getnet D, Swierczewski B, Jacobs A, Medina-Rojas M, Tyner S, Watters C, Antonic V. Evaluation of Pseudomonas aeruginosa pathogenesis and therapeutics in military-relevant animal infection models. APMIS 2021; 130:436-457. [PMID: 34132418 DOI: 10.1111/apm.13119] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/21/2021] [Indexed: 01/02/2023]
Abstract
Modern combat-related injuries are often associated with acute polytrauma. As a consequence of severe combat-related injuries, a dysregulated immune response results in serious infectious complications. The gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen that often causes life-threatening bloodstream, lung, bone, urinary tract, and wound infections following combat-related injuries. The rise in the number of multidrug-resistant P. aeruginosa strains has elevated its importance to civilian clinicians and military medicine. Development of novel therapeutics and treatment options for P. aeruginosa infections is urgently needed. During the process of drug discovery and therapeutic testing, in vivo testing in animal models is a critical step in the bench-to-bedside approach, and required for Food and Drug Administration approval. Here, we review current and past literature with a focus on combat injury-relevant animal models often used to understand infection development, the interplay between P. aeruginosa and the host, and evaluation of novel treatments. Specifically, this review focuses on the following animal infection models: wound, burn, bone, lung, urinary tract, foreign body, and sepsis.
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Affiliation(s)
- Alexander G Bobrov
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Derese Getnet
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Brett Swierczewski
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Anna Jacobs
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Maria Medina-Rojas
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Stuart Tyner
- US Army Medical Research and Development Command Military Infectious Diseases Research Program, Frederick, Maryland, USA
| | - Chase Watters
- Naval Medical Research Unit-3, Ghana Detachment, Accra, Ghana
| | - Vlado Antonic
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
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Vadakkan K, Hemapriya J, Selvaraj V. Quorum quenching intervened in vivo attenuation and immunological clearance enhancement by Solanum torvum root extract against Pseudomonas aeruginosa instigated pneumonia in Sprague Dawley rats. CLINICAL PHYTOSCIENCE 2019. [DOI: 10.1186/s40816-019-0120-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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IV Immunoglobulin for Acute Lung Injury and Bacteremia in Pseudomonas aeruginosa Pneumonia. Crit Care Med 2016; 44:e12-24. [PMID: 26317571 DOI: 10.1097/ccm.0000000000001271] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVES Virulent and multidrug-resistant Pseudomonas aeruginosa causes a lethal pneumonia, especially in patients who are artificially ventilated. It has been reported that the virulence mechanism used by P. aeruginosa, which is linked to acute lung injury, is strongly associated with the type III secretion system, and specific antibodies targeting this system have shown a protective effect in both experimental and clinical settings. We investigated the effect of administering IV immunoglobulins on P. aeruginosa pneumonia, including its associated bacteremia and mortality, although focusing especially on type III secretion system-associated P. aeruginosa virulence. DESIGN Prospective randomized and controlled animal study. SETTING University laboratory. SUBJECTS Male ICR mice. INTERVENTIONS Mice were infected intratracheally with a lethal dose of the virulent P. aeruginosa PA103 strain. IV immunoglobulin administration was examined in three different settings: 1) premixed; 2) pre-IV, prophylactic administration before bacterial infection; and 3) post-IV, therapeutic administration after bacterial infection. The effect of specific antigen titer depletion of IV immunoglobulins was also examined. MEASUREMENTS AND MAIN RESULTS Survival and body temperature were monitored for 24 hours. Bacteremia, cytokine concentration, myeloperoxidase activity, WBC counts in the blood, and lung bacterial load were evaluated. Survival improved significantly in mice that received IV immunoglobulins (p < 0.05). Lung edema, lung bacteriologic load, and bacteremia decreased significantly in the IV immunoglobulin-treated mice (p < 0.05). The mechanism of protection was associated with the presence of antibodies against both PcrV and some bacterial surface antigens in the IV immunoglobulins. CONCLUSIONS IV immunoglobulin administration had a significantly protective effect against lethal infection from virulent P. aeruginosa. Prophylactic IV immunoglobulin administration at the highest dose was comparable with that achieved by administrating a specific anti-PcrV polyclonal IgG into the mice. The mechanism of protection is likely to involve the synergic action of anti-PcrV titers and antibodies against some surface antigen(s) that block the type III secretion system-associated virulence of P. aeruginosa.
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Sawa T, Ito E, Nguyen VH, Haight M. Anti-PcrV antibody strategies against virulent Pseudomonas aeruginosa. Hum Vaccin Immunother 2015; 10:2843-52. [PMID: 25483637 DOI: 10.4161/21645515.2014.971641] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic bacterial pathogen that causes fatal acute lung infections in critically ill individuals. Its pathogenesis is associated with bacterial virulence conferred by the type III secretion system (TTSS), through which P. aeruginosa causes necrosis of the lung epithelium and disseminates into the circulation, resulting in bacteremia, sepsis, and mortality. TTSS allows P. aeruginosa to directly translocate cytotoxins into eukaryotic cells, inducing cell death. The P. aeruginosa V-antigen PcrV, a homolog of the Yersinia V-antigen LcrV, is an indispensable contributor to TTS toxin translocation. Vaccination against PcrV ensures the survival of challenged mice and decreases lung inflammation and injury. Both the rabbit polyclonal anti-PcrV antibody and the murine monoclonal anti-PcrV antibody, mAb166, inhibit TTS toxin translocation. mAb166 IgG was cloned, and a molecular engineered humanized anti-PcrV IgG antigen-binding fragment, KB001, was developed for clinical use. KB001 is currently undergoing Phase-II clinical trials for ventilator-associated pneumonia in France and chronic pneumonia in cystic fibrosis in USA. In these studies, KB001 has demonstrated its safety, a favorable pharmacokinetic profile, and promising potential as a nonantibiotic strategy to reduce airway inflammation and damage in P. aeruginosa pneumonia.
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Key Words
- CF, cystic fibrosis
- Fab, fragment antigen binding
- Fc, fragment crystallizable region
- MDR, multidrug resistant
- MDRP, multidrug resistant Pseudomonas aeruginosa
- P. aeruginosa, Pseudomonas aeruginosa
- PcrV
- Pseudomonas aeruginosa
- TTS, type III secretory
- TTSS, type III secretion system
- V-antigen
- VAP, ventilator-associated pneumonia
- antibody
- immunoglobulin G, IgG
- mAb, monoclonal antibody
- type III secretion system
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Affiliation(s)
- Teiji Sawa
- a Department of Anesthesiology ; Kyoto Prefectural University of Medicine ; Kyoto , Japan
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Sartorius A, Lu Q, Vieira S, Tonnellier M, Lenaour G, Goldstein I, Rouby JJ. Mechanical ventilation and lung infection in the genesis of air-space enlargement. Crit Care 2007; 11:R14. [PMID: 17274806 PMCID: PMC2147711 DOI: 10.1186/cc5680] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 11/22/2006] [Accepted: 02/02/2007] [Indexed: 11/24/2022] Open
Abstract
Introduction Air-space enlargement may result from mechanical ventilation and/or lung infection. The aim of this study was to assess how mechanical ventilation and lung infection influence the genesis of bronchiolar and alveolar distention. Methods Four groups of piglets were studied: non-ventilated-non-inoculated (controls, n = 5), non-ventilated-inoculated (n = 6), ventilated-non-inoculated (n = 6), and ventilated-inoculated (n = 8) piglets. The respiratory tract of intubated piglets was inoculated with a highly concentrated solution of Escherichia coli. Mechanical ventilation was maintained during 60 hours with a tidal volume of 15 ml/kg and zero positive end-expiratory pressure. After sacrifice by exsanguination, lungs were fixed for histological and lung morphometry analyses. Results Lung infection was present in all inoculated piglets and in five of the six ventilated-non-inoculated piglets. Mean alveolar and mean bronchiolar areas, measured using an analyzer computer system connected through a high-resolution color camera to an optical microscope, were significantly increased in non-ventilated-inoculated animals (+16% and +11%, respectively, compared to controls), in ventilated-non-inoculated animals (+49% and +49%, respectively, compared to controls), and in ventilated-inoculated animals (+95% and +118%, respectively, compared to controls). Mean alveolar and mean bronchiolar areas significantly correlated with the extension of lung infection (R = 0.50, p < 0.01 and R = 0.67, p < 0.001, respectively). Conclusion Lung infection induces bronchiolar and alveolar distention. Mechanical ventilation induces secondary lung infection and is associated with further air-space enlargement. The combination of primary lung infection and mechanical ventilation markedly increases air-space enlargement, the degree of which depends on the severity and extension of lung infection.
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Affiliation(s)
- Alfonso Sartorius
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Qin Lu
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Silvia Vieira
- Department of Internal Medicine, Faculty of Medicine, Federal University from Rio Grande do Sul, Intensive Care Unit, Hospital de Clinicas de Porto Alegre, Rua Ramiro Barcelos, 2350 – 90035-903 Porto Alegre/Rio Grande do Sul, Brazil
| | - Marc Tonnellier
- Medical Intensive Care Unit, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Gilles Lenaour
- Department of Pathology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Ivan Goldstein
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Jean-Jacques Rouby
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
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Robriquet L, Collet F, Tournoys A, Prangère T, Nevière R, Fourrier F, Guery BP. Intravenous administration of activated protein C in Pseudomonas-induced lung injury: impact on lung fluid balance and the inflammatory response. Respir Res 2006; 7:41. [PMID: 16553944 PMCID: PMC1435891 DOI: 10.1186/1465-9921-7-41] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Accepted: 03/22/2006] [Indexed: 01/11/2023] Open
Abstract
Background Acute lung injury (ALI) induces a coagulation/fibrinolysis imbalance and leads to fibrin deposition. The protein C pathway is an important regulator of the coagulation system and reduces the inflammatory response. The aim of the study was to examine the effects of recombinant human activated protein C (rhAPC) in the early phase of Pseudomonas aeruginosa (Pa)-induced lung injury. Methods The study was conducted in vivo on a rat model of Pa-induced ALI. Continuous intravenous (IV) rhAPC was administrated simultaneously with intratracheal (IT) Pa. We instilled into the airspaces a 5% bovine albumin solution with 1 μ(Ci of 125 I-albumin and injected IV 1 μ(Ci of 111In-albumin to measure lung liquid clearance (LLC) and endothelial injury. Cytokines levels (TNFα and IL-6) and thrombin-antithrombin (TAT) complexes were measured in blood and bronchoalveolar lavage fluid (BALF) at 4 hours. Four groups were compared: control (CTR), pneumonia (PNP) receiving IT Pa (0.5 ml/kg of 1 × 109 cfu), APC: IV rhAPC (300 μg/kg/h), A-PNP: IT Pa /IV rhAPC. Results Alveolar-capillary permeability was increased in the PNP versus the CTR group (0.28 ± 0.08 vs. 0.03 ± 0.01, p < 0.05). IV rhAPC in Pa-induced ALI led to further injury (0.47 ± 0.17 vs. 0.28 ± 0.08, p = 0.2). The LLC was significantly decreased in the A-PNP group compared to PNP group (9.1 ± (4.3% vs. 33.4 ± 2.6%, p < 0.05). The lung wet to dry weight ratio was significantly increased in the PNP group (4.62 ± 0.31) compared to the CTR group (3.87 ± 0.22, p < 0.05). IV rhAPC administration tends to increase this parameter in Pa-induced ALI (5.80 ± 0.66, p = 0.07). These findings were associated with a loss of inflammatory response compartmentalization measured by TNFα and IL-6 systemic levels. TAT complexes in BALF were increased in the A-PNP group (23.17 ± 2.89 ng/ml) compared to the CTR group (0.92 ± 0.17 ng/ml, p < 0.05) and the PNP group (11.06 ± 2.76 ng/ml, p < 0.05). Conclusion rhAPC reduces LLC following Pa-induced ALI and may influence pulmonary edema formation. The early massive fibrin formation is probably beneficial in ALI limiting both the extent of injury and permeability disorders.
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Affiliation(s)
- Laurent Robriquet
- EA 2689, Faculté de Médecine–Université de Lille 2- 1 place de Verdun, 59045 Lille Cedex, France
| | - François Collet
- EA 2689, Faculté de Médecine–Université de Lille 2- 1 place de Verdun, 59045 Lille Cedex, France
| | - Antoine Tournoys
- Laboratoire d'Hématologie CHRU Lille, Hopital Salengro, Bd Pr Leclecq, 59037 Lille Cedex, France
| | - Thierry Prangère
- Laboratoire de Biophysique- Service de Médecine Nucléaire–Faculté de Médecine/CHRU de Lille- 1 place de Verdun, 59045 Lille Cedex, France
| | - Rémi Nevière
- EA 2689, Faculté de Médecine–Université de Lille 2- 1 place de Verdun, 59045 Lille Cedex, France
| | - François Fourrier
- EA 2689, Faculté de Médecine–Université de Lille 2- 1 place de Verdun, 59045 Lille Cedex, France
| | - Benoît P Guery
- EA 2689, Faculté de Médecine–Université de Lille 2- 1 place de Verdun, 59045 Lille Cedex, France
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Allmond LR, Ajayi T, Moriyama K, Wiener-Kronish JP, Sawa T. V-antigen genotype and phenotype analyses of clinical isolates of Pseudomonas aeruginosa. J Clin Microbiol 2004; 42:3857-60. [PMID: 15297549 PMCID: PMC497603 DOI: 10.1128/jcm.42.8.3857-3860.2004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pcrV genotype was analyzed in clinical isolates of Pseudomonas aeruginosa which showed a negative phenotype for secretion of V-antigen PcrV. The suppression of PcrV secretion in these isolates was due not to a lack of the pcrV gene but rather to suppression of PcrV expression.
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Affiliation(s)
- Leonard R Allmond
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143-0542, USA
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Faure K, Fujimoto J, Shimabukuro DW, Ajayi T, Shime N, Moriyama K, Spack EG, Wiener-Kronish JP, Sawa T. Effects of monoclonal anti-PcrV antibody on Pseudomonas aeruginosa-induced acute lung injury in a rat model. JOURNAL OF IMMUNE BASED THERAPIES AND VACCINES 2003; 1:2. [PMID: 12943554 PMCID: PMC194171 DOI: 10.1186/1476-8518-1-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2003] [Accepted: 08/13/2003] [Indexed: 11/10/2022]
Abstract
BACKGROUND: The effects of the murine monoclonal anti-PcrV antibody Mab166 on acute lung injury induced by Pseudomonas aeruginosa were analyzed in a rat model. METHODS: Lung injury was induced by the instillation of P. aeruginosa strain PA103 directly into the left lungs of anesthetized rats. One hour after the bacterial instillation, rabbit polyclonal anti-PcrV IgG, murine monoclonal anti-PcrV IgG Mab166 or Mab166 Fab-fragments were administered intratracheally directly into the lungs. The degree of alveolar epithelial injury, amount of lung edema, decrease in oxygenation and extent of lung inflammation by histology were evaluated as independent parameters of acute lung injury. RESULTS: These parameters improved in rats that had received intratracheal instillation of either rabbit polyclonal anti-PcrV IgG, murine monoclonal anti-PcrV IgG Mab166 or Mab166 Fab-fragments in comparison with the control group. CONCLUSION: Mab166 and its Fab fragments have potential as adjuvant therapy for acute lung injury due to P. aeruginosa pneumonia.
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Affiliation(s)
- Karine Faure
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA94143-0542, U,S,A.
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Haddad JJ. Science review: redox and oxygen-sensitive transcription factors in the regulation of oxidant-mediated lung injury: role for hypoxia-inducible factor-1alpha. Crit Care 2003; 7:47-54. [PMID: 12617740 PMCID: PMC154109 DOI: 10.1186/cc1840] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A progressive rise of oxidative stress due to altered reduction-oxidation (redox) homeostasis appears to be one of the hallmarks of the processes that regulate gene transcription in physiology and pathophysiology. Reactive oxygen species and reactive nitrogen species serve as signaling messengers for the evolution and perpetuation of the inflammatory process that is often associated with the condition of oxidative stress, which involves genetic regulation. Changes in the pattern of gene expression through reactive oxygen species/reactive nitrogen species-sensitive regulatory transcription factors are crucial components of the machinery that determines cellular responses to oxidative/redox conditions. The present review describes the basic components of the intracellular oxidative/redox control machinery and its crucial regulation of oxygen-sensitive and redox-sensitive transcription factors within the context of lung injury. Particularly, the review discusses mechanical ventilation and NF-kappaB-mediated lung injury, ischemia-reperfusion and transplantation, compromised host defense and inflammatory stimuli, and hypoxemia and the crucial role of hypoxia-inducible factor in mediating lung injury. Changes in the pattern of gene expression through regulatory transcription factors are therefore crucial components of the machinery that determines cellular responses to oxidative/redox stress.
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Affiliation(s)
- John J Haddad
- Severinghaus-Radiometer Research Laboratories, Department of Anesthesia and Perioperative Care, University of California at San Francisco, School of Medicine, San Francisco, California, USA.
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Charles PE, Piroth L, Desbiolles N, Lequeu C, Martin L, Portier H, Chavanet P. New model of ventilator-associated pneumonia in immunocompetent rabbits. Crit Care Med 2002; 30:2278-83. [PMID: 12394956 DOI: 10.1097/00003246-200210000-00016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Despite the high rate of therapeutic failures in ventilator-associated pneumonia, up to now there has been no animal model specifically designed for antimicrobial evaluation. A rabbit model of ventilator-associated pneumonia is described for the first time in this study. DESIGN Prospective, randomized experimental study. SETTING An animal research laboratory. SUBJECTS Male New Zealand healthy rabbits (n = 44). INTERVENTIONS After oral intubation and an hour of mechanical ventilation, animals in the ventilator-associated pneumonia group (n = 22) were infected intrabronchially with a calibrated inoculum of. The nonventilated pneumonia group (n = 22) was composed of animals that received the same inoculum in the absence of mechanical ventilation. Rabbits from both groups were randomly killed 3, 6, 12, 24, or 48 hrs after inoculation. Pneumonia evaluation was based on histologic (macroscopic and microscopic score) and bacteriologic (bacterial count) findings. MAIN RESULTS Infected animals undergoing mechanical ventilation rapidly developed a progressive bilateral and multifocal pneumonia. Lung bacterial mean (sd) concentration was 6.48 (0.71) log10 colony-forming units (cfu) per gram of tissue at the 48th hour, whereas bacteremia occurred in most cases. In the nonventilated pneumonia group, pneumonia was less severe in terms of bacterial count (3.18 [1.86] log10 cfu/g; p <.05), and spleen cultures remained negative. In addition, microscopic examination revealed noninfectious lung injury in the ventilator-associated pneumonia group, especially hyaline membrane filling alveolar spaces. Of note, these features were never observed in the nonventilated pneumonia group. CONCLUSIONS An animal model of ventilator-associated pneumonia was obtained in immunocompetent rabbits. Histopathologic and bacteriologic features were similar to those found in humans. Obviously, pneumonia was more severe when animals underwent mechanical ventilation, especially in terms of systemic spread. Noninfectious lung injury corresponding to ventilation-induced lung injury may explain the difference. This model emphasizes the strong impact of both mechanical ventilation and infection on lung because they seem to act synergistically when causing alveolar damage. Moreover, it seems well suited to testing antimicrobial effectiveness.
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Wood GC, Boucher BA, Croce MA, Hanes SD, Herring VL, Fabian TC. Aerosolized ceftazidime for prevention of ventilator-associated pneumonia and drug effects on the proinflammatory response in critically ill trauma patients. Pharmacotherapy 2002; 22:972-82. [PMID: 12173800 DOI: 10.1592/phco.22.12.972.33596] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
STUDY OBJECTIVES To evaluate the safety and efficacy of aerosolized ceftazidime for prevention of ventilator-associated pneumonia (VAP) and to evaluate the effects of the drug on the proinflammatory response. DESIGN Prospective, randomized, double-blind, placebo-controlled clinical trial. SETTING University teaching hospital. PATIENTS Forty critically ill trauma patients at high risk for VAP Intervention. Within 48 hours of admission to the intensive care unit (ICU), patients were randomly assigned to receive aerosolized ceftazidime 250 mg every 12 hours or placebo (normal saline) for up to 7 days. Bronchoalveolar concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, and IL-8 were determined at baseline and the end of therapy (days 4-7). MEASUREMENTS AND MAIN RESULTS The frequency of VAP in patients receiving aerosolized ceftazidime was 73% lower than that in patients receiving placebo at ICU day 14 (15% vs 55%, p = 0.021), and 54% lower for the entire ICU stay (30% vs 65%, p = 0.022). No clinically significant changes in bacterial culture and sensitivity patterns were observed. No adverse events from aerosolized ceftazidime were reported. Pulmonary TNF-alpha, IL-beta, and IL-8 concentrations were attenuated in the ceftazidime group compared with those in the placebo group (p < 0.001, p = 0.02, and p = 0.003). The frequency of VAP was related directly to changes in TNF-alpha and IL-beta (p < 0.001, p = 0.02). CONCLUSIONS Aerosolized ceftazidime decreased the frequency of VAP in critically ill trauma patients, without adversely affecting ICU flora. Aerosolized ceftazidime also may attenuate the proinflammatory response in the lung.
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Affiliation(s)
- G Christopher Wood
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee, Memphis 38163, USA
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Bellais S, Mimoz O, Léotard S, Jacolot A, Petitjean O, Nordmann P. Efficacy of beta-lactams for treating experimentally induced pneumonia due to a carbapenem-hydrolyzing metallo-beta-lactamase-producing strain of Pseudomonas aeruginosa. Antimicrob Agents Chemother 2002; 46:2032-4. [PMID: 12019134 PMCID: PMC127240 DOI: 10.1128/aac.46.6.2032-2034.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A rat pneumonia model was established with a Pseudomonas aeruginosa strain that produced the plasmid-encoded metallocarbapenemase VIM-2. A significant decrease in lung bacterial titers was observed when imipenem, cefepime, ceftazidime, and piperacillin-tazobactam were given at the highest doses recommended for humans, despite their high MICs. Aztreonam at high doses produced a similar decrease in bacterial titers.
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Affiliation(s)
- Samuel Bellais
- Service de Bactériologie-Virologie-Hygiène, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Faculté de Médecine de Paris-Sud, 94275 Le Kremlin-Bicêtre, France
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Abstract
Widespread resistance problems exist today in a global sense because of the incorporation of antibiotics with a high resistance potential into animal feeds and because of the uncontrolled use of antibiotics with a high resistance potential in the clinical setting. The only proven method of controlling nonoutbreak resistance problems in hospitals is to limit the hospital formulary to antibiotics with little or no resistance potential. The control of multiresistant organisms in outbreaks occurring in hospitals is best contained using appropriate infection control containment measures. Physicians treating infections in the community, with all other factors being equal, should preferentially select antibiotics with a low resistance potential. The titles and headings of much of the resistance literature are misleading. Articles should not contain fluoroquinolone resistant in the title when ciprofloxacin-resistant organisms are described. Many articles concerning penicillin-resistant pneumococci are entitled fluoroquinolone-resistant S. pneumoniae. These articles describe ciprofloxacin-resistant S. pneumoniae and not resistance to other fluoroquinolones. The same error is perpetuated in describing third-generation cephalosporins and carbapenems. Virtually all of the resistance problems associated with third-generation cephalosporins and carbapenems are due to ceftazidime or imipenem. More precise titling in the literature would remind physicians that antibiotic resistance is related to a specific agent and not class phenomena.
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Affiliation(s)
- B A Cunha
- Infectious Disease Division, Winthrop-University Hospital, Mineola, New York, USA
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