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Wu T, Zhang Z, Li T, Dong X, Wu D, Zhu L, Xu K, Zhang Y. The type III secretion system facilitates systemic infections of Pseudomonas aeruginosa in the clinic. Microbiol Spectr 2024; 12:e0222423. [PMID: 38088541 PMCID: PMC10783026 DOI: 10.1128/spectrum.02224-23] [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: 05/27/2023] [Accepted: 11/14/2023] [Indexed: 01/13/2024] Open
Abstract
IMPORTANCE The identification of decisive virulence-associated genes in highly pathogenic P. aeruginosa isolates in the clinic is essential for diagnosis and the start of appropriate treatment. Over the past decades, P. aeruginosa ST463 has spread rapidly in East China and is highly resistant to β-lactams. Given the poor clinical outcome caused by this phenotype, detailed information regarding its decisive virulence genes and factors affecting virulence expression needs to be deciphered. Here, we demonstrate that the T3SS effector ExoU has toxic effects on mammalian cells and is required for virulence in the murine bloodstream infection model. Moreover, a functional downstream SpcU is required for ExoU secretion and cytotoxicity. This work highlights the potential role of ExoU in the pathogenesis of disease and provides a new perspective for further research on the development of new antimicrobials with antivirulence ability.
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Affiliation(s)
- Tiantian Wu
- Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhenchuan Zhang
- Research Center for Healthcare Data Science, Zhejiang Lab, Hangzhou, China
| | - Tong Li
- Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xu Dong
- Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Dan Wu
- Research and Service Center, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
- College of Food and Health, Zhejiang A&F University, Lin'an, Hangzhou, China
| | - Lixia Zhu
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Kaijin Xu
- Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ying Zhang
- Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, China
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2
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Fontana L, Strasfeld L, Hakki M. Pseudomonas aeruginosa ExoU-associated virulence in HCT recipients and patients with hematologic malignancies. Blood Adv 2023; 7:4035-4038. [PMID: 37216281 PMCID: PMC10410125 DOI: 10.1182/bloodadvances.2023009806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/15/2023] [Accepted: 04/01/2023] [Indexed: 05/24/2023] Open
Affiliation(s)
- Lauren Fontana
- Division of Infectious Diseases and International Medicine, University of Minnesota, Minneapolis, MN
| | - Lynne Strasfeld
- Division of Infectious Diseases, Oregon Health and Science University, Portland, OR
| | - Morgan Hakki
- Division of Infectious Diseases, Oregon Health and Science University, Portland, OR
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3
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Zhuang T, Hu M, Wang J, Mei L, Zhu X, Zhang H, Jin F, Shao J, Wang T, Wang C, Niu X, Wu D. Sodium houttuyfonate effectively treats acute pulmonary infection of Pseudomonas aeruginosa by affecting immunity and intestinal flora in mice. Front Cell Infect Microbiol 2022; 12:1022511. [PMID: 36530439 PMCID: PMC9751016 DOI: 10.3389/fcimb.2022.1022511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/14/2022] [Indexed: 12/04/2022] Open
Abstract
Introduction Pseudomonas aeruginosa is a major nosocomial pathogen that frequently causes ventilator-associated pneumonia in specific populations. Sodium houttuyfonate (SH) has shown mild antibacterial activity against P. aeruginosa in vitro, but the mechanism of potent antimicrobial activity of SH against P. aeruginosa infection in vivo remains unclear. Methods Here, using the mouse pneumonia model induced by P. aeruginosa nasal drip to explore the therapeutic effects of SH. Results We found that SH exhibits dose-dependent therapeutic effects of reducing P. aeruginosa burden and systemic inflammation in pneumonia mice. SH ameliorates inflammatory gene expression and production of inflammatory proteins, such as interleukin-6 (IL-6), nuclear factor kappa-B (NF-κB) and toll-like receptor 4 (TLR4), associated with the TLR4/NF-κB pathway in mice with P. aeruginosa pneumonia. Furthermore, we analyzed the intestinal flora of mice and found that compared with the model group, the abundance and diversity of beneficial bacterial flora of SH treatment groups increased significantly, suggesting that SH can improve the intestinal flora disorder caused by inflammation. In addition, SH improves alpha and beta diversity index and reduces species abundance differences of intestinal flora in pneumonia mice. Discussion Taken together, our presented results indicate that SH may effectively alleviate the acute pulmonary infection induced by P. aeruginosa by reducing the disturbance of regulating immunity and intestinal flora in mice.
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Affiliation(s)
- Tian Zhuang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China
| | - Mengxue Hu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China
| | - Jian Wang
- Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China,Pathology Department, First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei, China
| | - Longfei Mei
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China
| | - Xiaoxiao Zhu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China
| | - Haitao Zhang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China
| | - Feng Jin
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China
| | - Jing Shao
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China,Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China
| | - Tianming Wang
- Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China
| | - Changzhong Wang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China,Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China
| | - Xiaojia Niu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Research Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, China,Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China,*Correspondence: Daqiang Wu, ; Xiaojia Niu,
| | - Daqiang Wu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China,Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China,*Correspondence: Daqiang Wu, ; Xiaojia Niu,
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4
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Constantino-Teles P, Jouault A, Touqui L, Saliba AM. Role of Host and Bacterial Lipids in Pseudomonas aeruginosa Respiratory Infections. Front Immunol 2022; 13:931027. [PMID: 35860265 PMCID: PMC9289105 DOI: 10.3389/fimmu.2022.931027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa is one of the most common agents of respiratory infections and has been associated with high morbidity and mortality rates. The ability of P. aeruginosa to cause severe respiratory infections results from the coordinated action of a variety of virulence factors that promote bacterial persistence in the lungs. Several of these P. aeruginosa virulence mechanisms are mediated by bacterial lipids, mainly lipopolysaccharide, rhamnolipid, and outer membrane vesicles. Other mechanisms arise from the activity of P. aeruginosa enzymes, particularly ExoU, phospholipase C, and lipoxygenase A, which modulate host lipid signaling pathways. Moreover, host phospholipases, such as cPLA2α and sPLA2, are also activated during the infectious process and play important roles in P. aeruginosa pathogenesis. These mechanisms affect key points of the P. aeruginosa-host interaction, such as: i) biofilm formation that contributes to bacterial colonization and survival, ii) invasion of tissue barriers that allows bacterial dissemination, iii) modulation of inflammatory responses, and iv) escape from host defenses. In this mini-review, we present the lipid-based mechanism that interferes with the establishment of P. aeruginosa in the lungs and discuss how bacterial and host lipids can impact the outcome of P. aeruginosa respiratory infections.
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Affiliation(s)
- Pamella Constantino-Teles
- Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Albane Jouault
- Sorbonne Université, Centre de Recherche Saint-Antoine, Inserm, Institut Pasteur, Mucoviscidose et Bronchopathies Chroniques, Département Santé Globale, Paris, France
| | - Lhousseine Touqui
- Sorbonne Université, Centre de Recherche Saint-Antoine, Inserm, Institut Pasteur, Mucoviscidose et Bronchopathies Chroniques, Département Santé Globale, Paris, France
| | - Alessandra Mattos Saliba
- Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Rio de Janeiro State University, Rio de Janeiro, Brazil
- *Correspondence: Alessandra Mattos Saliba,
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5
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Hardy KS, Tuckey AN, Housley NA, Andrews J, Patel M, Al-Mehdi AB, Barrington RA, Cassel SL, Sutterwala FS, Audia JP. The Pseudomonas aeruginosa Type III Secretion System Exoenzyme Effector ExoU Induces Mitochondrial Damage in a Murine Bone Marrow-Derived Macrophage Infection Model. Infect Immun 2022; 90:e0047021. [PMID: 35130452 PMCID: PMC8929383 DOI: 10.1128/iai.00470-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that causes nosocomial pneumonia, urinary tract infections, and bacteremia. A hallmark of P. aeruginosa pathogenesis is disruption of host cell function by the type III secretion system (T3SS) and its cognate exoenzyme effectors. The T3SS effector ExoU is phospholipase A2 (PLA2) that targets the host cell plasmalemmal membrane to induce cytolysis and is an important virulence factor that mediates immune avoidance. In addition, ExoU has been shown to subvert the host inflammatory response in a noncytolytic manner. In primary bone marrow-derived macrophages (BMDMs), P. aeruginosa infection is sensed by the nucleotide-binding domain containing leucine-rich repeats-like receptor 4 (NLRC4) inflammasome, which triggers caspase-1 activation and inflammation. ExoU transiently inhibits NLRC4 inflammasome-mediated activation of caspase-1 and its downstream target, interleukin 1β (IL-1β), to suppress activation of inflammation. In the present study, we sought to identify additional noncytolytic virulence functions for ExoU and discovered an unexpected association between ExoU, host mitochondria, and NLRC4. We show that infection of BMDMs with P. aeruginosa strains expressing ExoU elicited mitochondrial oxidative stress. In addition, mitochondria and mitochondrion-associated membrane fractions enriched from infected cells exhibited evidence of autophagy activation, indicative of damage. The observation that ExoU elicited mitochondrial stress and damage suggested that ExoU may also associate with mitochondria during infection. Indeed, ExoU phospholipase A2 enzymatic activity was present in enriched mitochondria and mitochondrion-associated membrane fractions isolated from P. aeruginosa-infected BMDMs. Intriguingly, enriched mitochondria and mitochondrion-associated membrane fractions isolated from infected Nlrc4 homozygous knockout BMDMs displayed significantly lower levels of ExoU enzyme activity, suggesting that NLRC4 plays a role in the ExoU-mitochondrion association. These observations prompted us to assay enriched mitochondria and mitochondrion-associated membrane fractions for NLRC4, caspase-1, and IL-1β. NLRC4 and pro-caspase-1 were detected in enriched mitochondria and mitochondrion-associated membrane fractions isolated from noninfected BMDMs, and active caspase-1 and active IL-1β were detected in response to P. aeruginosa infection. Interestingly, ExoU inhibited mitochondrion-associated caspase-1 and IL-1β activation. The implications of ExoU-mediated effects on mitochondria and the NLRC4 inflammasome during P. aeruginosa infection are discussed.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Amanda N. Tuckey
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Nicole A. Housley
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Joel Andrews
- Mitchell Cancer Institute, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Mita Patel
- Department of Pharmcology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Abu-Bakr Al-Mehdi
- Department of Pharmcology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Robert A. Barrington
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Suzanne L. Cassel
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Fayyaz S. Sutterwala
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
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6
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Hardy KS, Tuckey AN, Renema P, Patel M, Al-Mehdi AB, Spadafora D, Schlumpf CA, Barrington RA, Alexeyev MF, Stevens T, Pittet JF, Wagener BM, Simmons JD, Alvarez DF, Audia JP. ExoU Induces Lung Endothelial Cell Damage and Activates Pro-Inflammatory Caspase-1 during Pseudomonas aeruginosa Infection. Toxins (Basel) 2022; 14:toxins14020152. [PMID: 35202178 PMCID: PMC8878379 DOI: 10.3390/toxins14020152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Accepted: 02/11/2022] [Indexed: 12/24/2022] Open
Abstract
The Gram-negative, opportunistic pathogen Pseudomonas aeruginosa utilizes a type III secretion system to inject exoenzyme effectors into a target host cell. Of the four best-studied exoenzymes, ExoU causes rapid cell damage and death. ExoU is a phospholipase A2 (PLA2) that hydrolyses host cell membranes, and P. aeruginosa strains expressing ExoU are associated with poor outcomes in critically ill patients with pneumonia. While the effects of ExoU on lung epithelial and immune cells are well studied, a role for ExoU in disrupting lung endothelial cell function has only recently emerged. Lung endothelial cells maintain a barrier to fluid and protein flux into tissue and airspaces and regulate inflammation. Herein, we describe a pulmonary microvascular endothelial cell (PMVEC) culture infection model to examine the effects of ExoU. Using characterized P. aeruginosa strains and primary clinical isolates, we show that strains expressing ExoU disrupt PMVEC barrier function by causing substantial PMVEC damage and lysis, in a PLA2-dependent manner. In addition, we show that strains expressing ExoU activate the pro-inflammatory caspase-1, in a PLA2-dependent manner. Considering the important roles for mitochondria and oxidative stress in regulating inflammatory responses, we next examined the effects of ExoU on reactive oxygen species production. Infection of PMVECs with P. aeruginosa strains expressing ExoU triggered a robust oxidative stress compared to strains expressing other exoenzyme effectors. We also provide evidence that, intriguingly, ExoU PLA2 activity was detectable in mitochondria and mitochondria-associated membrane fractions isolated from P. aeruginosa-infected PMVECs. Interestingly, ExoU-mediated activation of caspase-1 was partially inhibited by reactive oxygen species scavengers. Together, these data suggest ExoU exerts pleiotropic effects on PMVEC function during P. aeruginosa infection that may inhibit endothelial barrier and inflammatory functions.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Amanda N. Tuckey
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
| | - Phoibe Renema
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Biomedical Sciences, College of Allied Health, University of South Alabama Mobile, Mobile, AL 36688, USA
| | - Mita Patel
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Abu-Bakr Al-Mehdi
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Domenico Spadafora
- Flow Cytometry Core Lab, College of Medicine, University of South Alabama, Mobile, AL 36688, USA;
| | - Cody A. Schlumpf
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
| | - Robert A. Barrington
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Flow Cytometry Core Lab, College of Medicine, University of South Alabama, Mobile, AL 36688, USA;
| | - Mikhail F. Alexeyev
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Troy Stevens
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, Birmingham School of Medicine, University of Alabama, Birmingham, AL 35294, USA; (J.-F.P.); (B.M.W.)
| | - Brant M. Wagener
- Department of Anesthesiology and Perioperative Medicine, Birmingham School of Medicine, University of Alabama, Birmingham, AL 35294, USA; (J.-F.P.); (B.M.W.)
| | - Jon D. Simmons
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Surgery, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Diego F. Alvarez
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Physiology and Pharmacology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX 77304, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Correspondence:
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7
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Hardy KS, Tessmer MH, Frank DW, Audia JP. Perspectives on the Pseudomonas aeruginosa Type III Secretion System Effector ExoU and Its Subversion of the Host Innate Immune Response to Infection. Toxins (Basel) 2021; 13:880. [PMID: 34941717 PMCID: PMC8708460 DOI: 10.3390/toxins13120880] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/19/2021] [Accepted: 12/04/2021] [Indexed: 12/02/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic, Gram-negative pathogen and an important cause of hospital acquired infections, especially in immunocompromised patients. Highly virulent P. aeruginosa strains use a type III secretion system (T3SS) to inject exoenzyme effectors directly into the cytoplasm of a target host cell. P. aeruginosa strains that express the T3SS effector, ExoU, associate with adverse outcomes in critically ill patients with pneumonia, owing to the ability of ExoU to rapidly damage host cell membranes and subvert the innate immune response to infection. Herein, we review the structure, function, regulation, and virulence characteristics of the T3SS effector ExoU, a highly cytotoxic phospholipase A2 enzyme.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, AL 36608, USA;
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, AL 36608, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Maxx H. Tessmer
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA;
| | - Dara W. Frank
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, AL 36608, USA;
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, AL 36608, USA
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8
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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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Bouillot S, Pont S, Gallet B, Moriscot C, Deruelle V, Attrée I, Huber P. Inflammasome activation by Pseudomonas aeruginosa's ExlA pore-forming toxin is detrimental for the host. Cell Microbiol 2020; 22:e13251. [PMID: 32779854 DOI: 10.1111/cmi.13251] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/24/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
During acute Pseudomonas aeruginosa infection, the inflammatory response is essential for bacterial clearance. Neutrophil recruitment can be initiated following the assembly of an inflammasome within sentinel macrophages, leading to activation of caspase-1, which in turn triggers macrophage pyroptosis and IL-1β/IL-18 maturation. Inflammasome formation can be induced by a number of bacterial determinants, including Type III secretion systems (T3SSs) or pore-forming toxins, or, alternatively, by lipopolysaccharide (LPS) via caspase-11 activation. Surprisingly, previous studies indicated that a T3SS-induced inflammasome increased pathogenicity in mouse models of P. aeruginosa infection. Here, we investigated the immune reaction of mice infected with a T3SS-negative P. aeruginosa strain (IHMA879472). Virulence of this strain relies on ExlA, a secreted pore-forming toxin. IHMA879472 promoted massive neutrophil infiltration in infected lungs, owing to efficient priming of toll-like receptors, and thus enhanced the expression of inflammatory proteins including pro-IL-1β and TNF-α. However, mature-IL-1β and IL-18 were undetectable in wild-type mice, suggesting that ExlA failed to effectively activate caspase-1. Nevertheless, caspase-1/11 deficiency improved survival following infection with IHMA879472, as previously described for T3SS+ bacteria. We conclude that the detrimental effect associated with the ExlA-induced inflammasome is probably not due to hyperinflammation, rather it stems from another inflammasome-dependent process.
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Affiliation(s)
- Stéphanie Bouillot
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Stéphane Pont
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Benoit Gallet
- Institut de Biologie Structurale, CEA, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Christine Moriscot
- Institut de Biologie Structurale, CEA, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Vincent Deruelle
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Ina Attrée
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Philippe Huber
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
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10
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Hasannejad-Bibalan M, Jafari A, Sabati H, Goswami R, Jafaryparvar Z, Sedaghat F, Sedigh Ebrahim-Saraie H. Risk of type III secretion systems in burn patients with Pseudomonas aeruginosa wound infection: A systematic review and meta-analysis. Burns 2020; 47:538-544. [PMID: 32532479 DOI: 10.1016/j.burns.2020.04.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 03/17/2020] [Accepted: 04/23/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE The pathogenesis of Pseudomonas aeruginosa is multifactorial and attributed to the production of several cell-associated and extracellular virulence factors including those implicated in adherence, iron uptake, exoenzymes (Exo) and exotoxins. The present study aimed to determine the prevalence of type III secretion systems (T3SS) effectors in Iranian burn patients with P. aeruginosa wound infection. METHODS A systematic search was conducted to identify papers published by Iranian authors in the Web of Science, PubMed, Scopus, Embase, and Google Scholar electronic databases during the period of January, 2000 to December, 2018. Publications which met our inclusion criteria were selected for data extraction and analysis by Comprehensive Meta-Analysis Software. The inclusion criteria were articles that include burn patients with a wound infection caused by P. aeruginosa, and reported the prevalence of aimed exoenzymes. RESULTS Ten publications were selected out of 15 full-text reviewed articles with the inclusion criteria. Of ten studies, the pooled prevalence of ExoS producing isolates was estimated at 57.1% (95% CI: 40.3-72.5%). Five studies reported the prevalence of ExoU and ExoT, from which, the pooled prevalence of ExoU and ExoT producing isolates was estimated at 51.4% (95% CI: 31.4-70.9%) and 86.4% (95% CI: 48.1-97.8%), respectively. Four studies reported the prevalence of ExoY, from which, the pooled prevalence of ExoY producing isolates was estimated at 79.0% (95% CI: 48.6-93.8%). CONCLUSION Our results showed a remarkable prevalence of T3SS-positive genotype in patients with burn injuries. These findings provided attractive targets for new therapeutic strategies for burn patients who were infected with cytotoxin-producing P. aeruginosa.
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Affiliation(s)
| | - Alireza Jafari
- Urology Research Center, Razi Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Hoda Sabati
- Biotechnology and Biological Science Research Center, Faculty of Science, Shahid Chamran University of Ahvaz, Iran
| | - Rajendra Goswami
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - Zakiyeh Jafaryparvar
- Razi Clinical Research Development Unit, Razi Hospital, Guilan University of Medical Sciences, Rasht, Iran
| | - Farzaneh Sedaghat
- Student Research Committee, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Hadi Sedigh Ebrahim-Saraie
- Razi Clinical Research Development Unit, Razi Hospital, Guilan University of Medical Sciences, Rasht, Iran.
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11
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Cabral MP, Correia A, Vilanova M, Gärtner F, Moscoso M, García P, Vallejo JA, Pérez A, Francisco-Tomé M, Fuentes-Valverde V, Bou G. A live auxotrophic vaccine confers mucosal immunity and protection against lethal pneumonia caused by Pseudomonas aeruginosa. PLoS Pathog 2020; 16:e1008311. [PMID: 32040500 PMCID: PMC7034913 DOI: 10.1371/journal.ppat.1008311] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 02/21/2020] [Accepted: 01/06/2020] [Indexed: 12/28/2022] Open
Abstract
Pseudomonas aeruginosa is one of the leading causes of nosocomial pneumonia and its associated mortality. Moreover, extensively drug-resistant high-risk clones are globally widespread, presenting a major challenge to the healthcare systems. Despite this, no vaccine is available against this high-concerning pathogen. Here we tested immunogenicity and protective efficacy of an experimental live vaccine against P. aeruginosa pneumonia, consisting of an auxotrophic strain which lacks the key enzyme involved in D-glutamate biosynthesis, a structural component of the bacterial cell wall. As the amounts of free D-glutamate in vivo are trace substances in most cases, blockage of the cell wall synthesis occurs, compromising the growth of this strain, but not its immunogenic properties. Indeed, when delivered intranasally, this vaccine stimulated production of systemic and mucosal antibodies, induced effector memory, central memory and IL-17A-producing CD4+ T cells, and recruited neutrophils and mononuclear phagocytes into the airway mucosa. A significant improvement in mice survival after lung infection caused by ExoU-producing PAO1 and PA14 strains was observed. Nearly one third of the mice infected with the XDR high-risk clone ST235 were also protected. These findings highlight the potential of this vaccine for the control of acute pneumonia caused by this bacterial pathogen. Pseudomonas aeruginosa is an opportunistic bacterium and one of the most common causes of healthcare-associated diseases, including acute pneumonia, causing high mortality within immunocompromised hosts. Most of these infections are strikingly difficult to treat using conventional antibiotic therapies, since this microorganism displays high intrinsic resistance to a wide range of antibiotics. Moreover, to date, no vaccine is available for prevention. Here we used a mutated bacterial strain, which is unable to replicate in vivo and to cause disease, as a live vaccine against acute pneumonia caused by this pathogen. When applied intranasally, this vaccine induced immunity both at local and distant body sites, activating immune cells which were recruited into the airway mucosa. This evoked immune response reduced the number of non-surviving mice after infection with two cytotoxic P. aeruginosa strains causing acute lung infection. Some protection was also observed against an internationally disseminated cytotoxic strain. These data indicate that this is a promising vaccine candidate against P. aeruginosa-pneumonia.
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Affiliation(s)
- Maria P. Cabral
- Department of Microbiology, University Hospital A Coruña (CHUAC)–Biomedical Research Institute A Coruña (INIBIC), A Coruña, Spain
| | - Alexandra Correia
- i3S –Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC–Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Manuel Vilanova
- i3S –Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC–Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Fátima Gärtner
- i3S –Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
- IPATIMUP—Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Miriam Moscoso
- Department of Microbiology, University Hospital A Coruña (CHUAC)–Biomedical Research Institute A Coruña (INIBIC), A Coruña, Spain
| | - Patricia García
- Department of Microbiology, University Hospital A Coruña (CHUAC)–Biomedical Research Institute A Coruña (INIBIC), A Coruña, Spain
| | - Juan A. Vallejo
- Department of Microbiology, University Hospital A Coruña (CHUAC)–Biomedical Research Institute A Coruña (INIBIC), A Coruña, Spain
| | - Astrid Pérez
- Department of Microbiology, University Hospital A Coruña (CHUAC)–Biomedical Research Institute A Coruña (INIBIC), A Coruña, Spain
| | - Mónica Francisco-Tomé
- Department of Microbiology, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | - Víctor Fuentes-Valverde
- Department of Microbiology, University Hospital A Coruña (CHUAC)–Biomedical Research Institute A Coruña (INIBIC), A Coruña, Spain
| | - Germán Bou
- Department of Microbiology, University Hospital A Coruña (CHUAC)–Biomedical Research Institute A Coruña (INIBIC), A Coruña, Spain
- * E-mail:
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Abstract
PURPOSE OF REVIEW This review details the management of Pseudomonas aeruginosa infections covering both current and future treatment options that are and may be available for the clinicians. RECENT FINDINGS Pseudomonas aeruginosa infections are a great concern in hospital-acquired infections with very limited therapeutic options. The increasing antibiotic resistance has led to a need for different treatment choices that range from the use of new antibiotics to new nonantibiotic alternative agents to kill or disarm the pathogen. SUMMARY New molecules such as ceftolozane-tazobactam, ceftazidime-avibactam, and imipenem-relebactam have shown an adequate activity against P. aeruginosa, especially against multidrug resistance strains. Other nonantibiotic alternative treatments, such as antibodies, bacteriocins or phage therapy, have shown promising results, but future clinical studies are needed.
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13
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Subedi D, Kohli GS, Vijay AK, Willcox M, Rice SA. Accessory genome of the multi-drug resistant ocular isolate of Pseudomonas aeruginosa PA34. PLoS One 2019; 14:e0215038. [PMID: 30986237 PMCID: PMC6464166 DOI: 10.1371/journal.pone.0215038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 03/25/2019] [Indexed: 02/07/2023] Open
Abstract
Bacteria can acquire an accessory genome through the horizontal transfer of genetic elements from non-parental lineages. This leads to rapid genetic evolution allowing traits such as antibiotic resistance and virulence to spread through bacterial communities. The study of complete genomes of bacterial strains helps to understand the genomic traits associated with virulence and antibiotic resistance. We aimed to investigate the complete accessory genome of an ocular isolate of Pseudomonas aeruginosa strain PA34. We obtained the complete genome of PA34 utilising genome sequence reads from Illumina and Oxford Nanopore Technology followed by PCR to close any identified gaps. In-depth genomic analysis was performed using various bioinformatics tools. The susceptibility to heavy metals and cytotoxicity was determined to confirm expression of certain traits. The complete genome of PA34 includes a chromosome of 6.8 Mbp and two plasmids of 95.4 Kbp (pMKPA34-1) and 26.8 Kbp (pMKPA34-2). PA34 had a large accessory genome of 1,213 genes and had 543 unique genes not present in other strains. These exclusive genes encoded features related to metal and antibiotic resistance, phage integrase and transposons. At least 24 genomic islands (GIs) were predicated in the complete chromosome, of which two were integrated into novel sites. Eleven GIs carried virulence factors or replaced pathogenic genes. A bacteriophage carried the aminoglycoside resistance gene (AAC(3)-IId). The two plasmids carried other six antibiotic resistance genes. The large accessory genome of this ocular isolate plays a large role in shaping its virulence and antibiotic resistance.
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Affiliation(s)
- Dinesh Subedi
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
- * E-mail:
| | - Gurjeet Singh Kohli
- The Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ajay Kumar Vijay
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Mark Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Scott A. Rice
- The Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- The ithree Institute, The University of Technology Sydney, Sydney, New South Wales, Australia
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14
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Hoggarth A, Weaver A, Pu Q, Huang T, Schettler J, Chen F, Yuan X, Wu M. Mechanistic research holds promise for bacterial vaccines and phage therapies for Pseudomonas aeruginosa. DRUG DESIGN DEVELOPMENT AND THERAPY 2019; 13:909-924. [PMID: 30936684 PMCID: PMC6431001 DOI: 10.2147/dddt.s189847] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vaccines for Pseudomonas aeruginosa have been of longstanding interest to immunologists, bacteriologists, and clinicians, due to the widespread prevalence of hospital-acquired infection. As P. aeruginosa becomes increasingly antibiotic resistant, there is a dire need for novel treatments and preventive vaccines. Despite intense efforts, there currently remains no vaccine on the market to combat this dangerous pathogen. This article summarizes current and past vaccines under development that target various constituents of P. aeruginosa. Targeting lipopolysaccharides and O-antigens have shown some promise in preventing infection. Recombinant flagella and pili that target TLR5 have been utilized to combat P. aeruginosa by blocking its motility and adhesion. The type 3 secretion system components, such as needle-like structure PcrV or exotoxin PopB, are also potential vaccine targets. Outer membrane proteins including OprF and OprI are newer representatives of vaccine candidates. Live attenuated vaccines are a focal point in this review, and are also considered for novel vaccines. In addition, phage therapy is revived as an effective option for treating refractory infections after failure with antibiotic treatment. Many of the aforementioned vaccines act on a single target, thus lacking a broad range of protection. Recent studies have shown that mixtures of vaccines and combination approaches may significantly augment immunogenicity, thereby increasing their preventive and therapeutic potential.
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Affiliation(s)
- Austin Hoggarth
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Andrew Weaver
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Qinqin Pu
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Ting Huang
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA, .,Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, China
| | - Jacob Schettler
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Feng Chen
- Pulmonary and Allergy Institute, Affiliated Hospital of Southwestern Medical University, Luzhou, China
| | - Xiefang Yuan
- Pulmonary and Allergy Institute, Affiliated Hospital of Southwestern Medical University, Luzhou, China
| | - Min Wu
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
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15
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Development of a Broad-Spectrum Antimicrobial Combination for the Treatment of Staphylococcus aureus and Pseudomonas aeruginosa Corneal Infections. Antimicrob Agents Chemother 2018; 63:AAC.01929-18. [PMID: 30420484 DOI: 10.1128/aac.01929-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/25/2018] [Indexed: 10/28/2022] Open
Abstract
Staphylococcus aureus and Pseudomonas aeruginosa are two of the most common causes of bacterial keratitis and corresponding corneal blindness. Accordingly, such infections are predominantly treated with broad-spectrum fluoroquinolones, such as moxifloxacin. Yet, the rising fluoroquinolone resistance has necessitated the development of alternative therapeutic options. Herein, we describe the development of a polymyxin B-trimethoprim (PT) ophthalmic formulation containing the antibiotic rifampin, which exhibits synergistic antimicrobial activity toward a panel of contemporary ocular clinical S. aureus and P. aeruginosa isolates, low spontaneous resistance frequency, and in vitro bactericidal kinetics and antibiofilm activities equaling or exceeding the antimicrobial properties of moxifloxacin. The PT plus rifampin combination also demonstrated increased efficacy in comparison to those of either commercial PT or moxifloxacin in a murine keratitis model of infection, resulting in bacterial clearance of 70% in the animals treated. These results suggest that the combination of PT and rifampin may represent a novel antimicrobial agent in the treatment of bacterial keratitis.
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16
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Schaefers MM, Duan B, Mizrahi B, Lu R, Reznor G, Kohane DS, Priebe GP. PLGA-encapsulation of the Pseudomonas aeruginosa PopB vaccine antigen improves Th17 responses and confers protection against experimental acute pneumonia. Vaccine 2018; 36:6926-6932. [PMID: 30314911 DOI: 10.1016/j.vaccine.2018.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 07/20/2018] [Accepted: 10/03/2018] [Indexed: 12/26/2022]
Abstract
The Pseudomonas aeruginosa type III secretion system protein PopB and its chaperon protein PcrH, when co-administered with the adjuvant curdlan, elicit Th17 responses after intranasal immunization of mice. These PopB/PcrH-curdlan vaccines protect mice against acute lethal pneumonia in an IL-17-dependent fashion involving CD4 helper T cells secreting IL-17 (Th17 cells). In this study, we tested whether encapsulation of PopB/PcrH in poly-lactic-co-glycolic acid (PLGA) nanoparticles could elicit Th17 responses to PopB. Recombinant PopB/PcrH or PcrH alone was encapsulated into PLGA nanoparticles. Mice (FVB/N) were intranasally immunized with the PLGA-PopB/PcrH nanoparticles, PLGA-PcrH nanoparticles, PLGA alone, or PopB/PcrH alone. The protective efficacy was assessed in an acute lung infection model with a lethal dose of an ExoU-producing version of P. aeruginosa strain PAO1. Th17 responses were assayed by intracellular flow cytometry and by ELISA for IL-17 in supernatants of splenocytes co-cultured with purified PopB/PcrH. PLGA-PopB/PcrH-immunized mice showed 3-4-fold higher Th17 responses both in the lung and in the spleen compared to mice immunized with empty PLGA or PopB/PcrH alone. After challenge with P. aeruginosa, PLGA-PopB/PcrH-immunized mice showed significantly lower bacterial counts in the lungs and improved survival. In conclusion, encapsulation of PopB/PcrH in PLGA nanoparticles can elicit Th17 responses to intranasal vaccination and protect mice against acute lethal P. aeruginosa pneumonia.
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Affiliation(s)
- Matthew M Schaefers
- Division of Critical Care Medicine, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115 USA; Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA.
| | - Biyan Duan
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA
| | - Boaz Mizrahi
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Roger Lu
- Division of Critical Care Medicine, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115 USA; Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA
| | - Gally Reznor
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Daniel S Kohane
- Division of Critical Care Medicine, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115 USA; Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Gregory P Priebe
- Division of Critical Care Medicine, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115 USA; Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA
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17
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Saputra IWAGM, Mertaniasih NM, Fatmawati NND. Positivity of ExoU Gene of Type III Secretion System and Fluoroquinolone Resistance of Psedomonas aeruginosa from Sputum of Nosocomial Pneumonia Patients in Sanglah Hospital, Bali. FOLIA MEDICA INDONESIANA 2018. [DOI: 10.20473/fmi.v54i2.8863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pseudomonas aeruginosa is one of the Gram-negative rods bacteria that frequently cause nosocomial pneumonia. One of the main virulent effector proteins on Type III secretion system (TTSS) of P. aeruginosa is Exoenzyme U ( ExoU). ExoU works as a phospholipase A2 activity and exhibits lung tissue injury effect in pneumonia. As an antibiotic that has activity against P. aeruginosa, fluoroquinolone resistance has increased as many as three fold since the last decade. Infections caused by P. aeruginosa that are fluoroquinolone resistant and positive for ExoU gene show worse clinical outcome. The aim of this study was to determine the positivity of ExoU gene TTSS and fluoroquinolone resistance of P. aeruginosa that isolated from sputum of nosocomial pneumonia patients in Sanglah Hospital, Bali. P. aeruginosa isolated from sputum of patient that diagnosed as nosocomial pneumonia, isolates had been identified phenotypically by Vitek2 Compact system (bioMérieux, Inc., Marcy-l'Etoile - France), and then continued by genotypic detection by PCR. The susceptibility testing of P. aeruginosa isolates to Ciprofloxacin were conducted by Vitek2 Compact, whereas ExoU genes were detected by PCR. Fifty-three P. aeruginosa isolates were identified in this study, in which 35 isolates (66.1%) had ExoU gene and 22 isolates (41.5%) were resistant to Ciprofloxacin. Based on nosocomial pneumonia type, the highest proportion of isolates genotipically ExoU+ and phenotypically Ciprofloxacin were on VAP group accounted for 57.1% and 54.5%, respectively. Chi-square analysis showed significant correlation between Ciprofloxacin resistance and ExoU gene (p=0.001). As a conclusion, the positivity of ExoU+ isolates were more likely found in Ciprofloxacin resistant group.
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18
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Casasanta MA, Yoo CC, Smith HB, Duncan AJ, Cochrane K, Varano AC, Allen-Vercoe E, Slade DJ. A chemical and biological toolbox for Type Vd secretion: Characterization of the phospholipase A1 autotransporter FplA from Fusobacterium nucleatum. J Biol Chem 2017; 292:20240-20254. [PMID: 29021252 PMCID: PMC5724010 DOI: 10.1074/jbc.m117.819144] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/10/2017] [Indexed: 01/28/2023] Open
Abstract
Fusobacterium nucleatum is an oral pathogen that is linked to multiple human infections and colorectal cancer. Strikingly, F. nucleatum achieves virulence in the absence of large, multiprotein secretion systems (Types I, II, III, IV, and VI), which are widely used by Gram-negative bacteria for pathogenesis. By contrast, F. nucleatum strains contain genomic expansions of Type V secreted effectors (autotransporters) that are critical for host cell adherence, invasion, and biofilm formation. Here, we present the first characterization of an F. nucleatum Type Vd phospholipase class A1 autotransporter (strain ATCC 25586, gene FN1704) that we hereby rename Fusobacterium phospholipase autotransporter (FplA). Biochemical analysis of multiple Fusobacterium strains revealed that FplA is expressed as a full-length 85-kDa outer membrane–embedded protein or as a truncated phospholipase domain that remains associated with the outer membrane. Whereas the role of Type Vd secretion in bacteria remains unidentified, we show that FplA binds with high affinity to host phosphoinositide-signaling lipids, revealing a potential role for this enzyme in establishing an F. nucleatum intracellular niche. To further analyze the role of FplA, we developed an fplA gene knock-out strain, which will guide future in vivo studies to determine its potential role in F. nucleatum pathogenesis. In summary, using recombinant FplA constructs, we have identified a biochemical toolbox that includes lipid substrates for enzymatic assays, potent inhibitors, and chemical probes to detect, track, and characterize the role of Type Vd secreted phospholipases in Gram-negative bacteria.
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Affiliation(s)
- Michael A Casasanta
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - Christopher C Yoo
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - Hans B Smith
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - Alison J Duncan
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - Kyla Cochrane
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4S6, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, Simon Fraser University, Vancouver, British Columbia V5A 1S6, Canada
| | - Ann C Varano
- Virginia Tech Carilion Research Institute, Roanoke, Virginia 24016
| | - Emma Allen-Vercoe
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Daniel J Slade
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061.
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Pazos MA, Lanter BB, Yonker LM, Eaton AD, Pirzai W, Gronert K, Bonventre JV, Hurley BP. Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration. PLoS Pathog 2017; 13:e1006548. [PMID: 28771621 PMCID: PMC5557605 DOI: 10.1371/journal.ppat.1006548] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/15/2017] [Accepted: 07/22/2017] [Indexed: 12/21/2022] Open
Abstract
Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3), initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4). We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2) activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment. Pseudomonas aeruginosa is an opportunistic pathogen that causes acute pneumonia in immune compromised patients, and infects 70–80% of patients suffering from cystic fibrosis. Infections can result in excessive airway inflammation, which lead to immune-mediated lung damage, in particular through the action of recruited white blood cells known as neutrophils. Certain strains of P. aeruginosa produce the exotoxin ExoU, which has been associated with increased virulence. ExoU causes host cell lysis by hydrolyzing host membrane lipids through its phospholipase activity. However, host phospholipases play a key role in immune signaling by mediating the production of lipids known as eicosanoids. We investigated whether separate from its cytolytic activity, ExoU could modulate host immune responses through its phospholipase activity by hijacking eicosanoid production. Using in vitro and in vivo models of neutrophil recruitment, we find that ExoU producing strains of P. aeruginosa elicit higher levels of the eicosanoid chemoattractant leukotriene B4 from migrated neutrophils. This results in increased neutrophil transepithelial migration. This work reveals a new mechanism for how bacterial pathogens alter our immune function, and highlights a new potential therapeutic strategy for moderating Pseudomonas pathogenesis in patients with cystic fibrosis and acute pneumonia.
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Affiliation(s)
- Michael A. Pazos
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bernard B. Lanter
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lael M. Yonker
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alex D. Eaton
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
| | - Waheed Pirzai
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
| | - Karsten Gronert
- Vision Science Program, School of Optometry, University of California at Berkeley, Berkeley, California, United States of America
| | - Joseph V. Bonventre
- Renal Division and Biomedical Engineering Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bryan P. Hurley
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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20
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Fischer AW, Anderson DM, Tessmer MH, Frank DW, Feix JB, Meiler J. Structure and Dynamics of Type III Secretion Effector Protein ExoU As determined by SDSL-EPR Spectroscopy in Conjunction with De Novo Protein Folding. ACS OMEGA 2017; 2:2977-2984. [PMID: 28691114 PMCID: PMC5494639 DOI: 10.1021/acsomega.7b00349] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/15/2017] [Indexed: 05/24/2023]
Abstract
ExoU is a 74 kDa cytotoxin that undergoes substantial conformational changes as part of its function, that is, it has multiple thermodynamically stable conformations that interchange depending on its environment. Such flexible proteins pose unique challenges to structural biology: (1) not only is it often difficult to determine structures by X-ray crystallography for all biologically relevant conformations because of the flat energy landscape (2) but also experimental conditions can easily perturb the biologically relevant conformation. The first challenge can be overcome by applying orthogonal structural biology techniques that are capable of observing alternative, biologically relevant conformations. The second challenge can be addressed by determining the structure in the same biological state with two independent techniques under different experimental conditions. If both techniques converge to the same structural model, the confidence that an unperturbed biologically relevant conformation is observed increases. To this end, we determine the structure of the C-terminal domain of the effector protein, ExoU, from data obtained by electron paramagnetic resonance spectroscopy in conjunction with site-directed spin labeling and in silico de novo structure determination. Our protocol encompasses a multimodule approach, consisting of low-resolution topology sampling, clustering, and high-resolution refinement. The resulting model was compared with an ExoU model in complex with its chaperone SpcU obtained previously by X-ray crystallography. The two models converged to a minimal RMSD100 of 3.2 Å, providing evidence that the unbound structure of ExoU matches the fold observed in complex with SpcU.
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Affiliation(s)
- Axel W. Fischer
- Department
of Chemistry and Center for Structural Biology, Vanderbilt
University, Nashville, Tennessee 37232, United States
| | - David M. Anderson
- Department
of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Maxx H. Tessmer
- Department of Biophysics and Department of
Microbiology and Immunology, Medical College
of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - Dara W. Frank
- Department of Biophysics and Department of
Microbiology and Immunology, Medical College
of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - Jimmy B. Feix
- Department of Biophysics and Department of
Microbiology and Immunology, Medical College
of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - Jens Meiler
- Department
of Chemistry and Center for Structural Biology, Vanderbilt
University, Nashville, Tennessee 37232, United States
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21
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Pseudomonas aeruginosa Exolysin promotes bacterial growth in lungs, alveolar damage and bacterial dissemination. Sci Rep 2017; 7:2120. [PMID: 28522850 PMCID: PMC5437091 DOI: 10.1038/s41598-017-02349-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/10/2017] [Indexed: 11/18/2022] Open
Abstract
Exolysin (ExlA) is a recently-identified pore-forming toxin secreted by a subset of Pseudomonas aeruginosa strains identified worldwide and devoid of Type III secretion system (T3SS), a major virulence factor. Here, we characterized at the ultrastructural level the lesions caused by an ExlA-secreting strain, CLJ1, in mouse infected lungs. CLJ1 induced necrotic lesions in pneumocytes and endothelial cells, resulting in alveolo-vascular barrier breakdown. Ectopic expression of ExlA in an exlA-negative strain induced similar tissue injuries. In addition, ExlA conferred on bacteria the capacity to proliferate in lungs and to disseminate in secondary organs, similar to bacteria possessing a functional T3SS. CLJ1 did not promote a strong neutrophil infiltration in the alveoli, owing to the weak pro-inflammatory cytokine reaction engendered by the strain. However, CLJ1 was rapidly eliminated from the blood in a bacteremia model, suggesting that it can be promptly phagocytosed by immune cells. Together, our study ascribes to ExlA-secreting bacteria the capacity to proliferate in the lung and to damage pulmonary tissues, thereby promoting metastatic infections, in absence of substantial immune response exacerbation.
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22
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Cong X, Hubmayr RD, Li C, Zhao X. Plasma membrane wounding and repair in pulmonary diseases. Am J Physiol Lung Cell Mol Physiol 2017; 312:L371-L391. [PMID: 28062486 PMCID: PMC5374305 DOI: 10.1152/ajplung.00486.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/12/2022] Open
Abstract
Various pathophysiological conditions such as surfactant dysfunction, mechanical ventilation, inflammation, pathogen products, environmental exposures, and gastric acid aspiration stress lung cells, and the compromise of plasma membranes occurs as a result. The mechanisms necessary for cells to repair plasma membrane defects have been extensively investigated in the last two decades, and some of these key repair mechanisms are also shown to occur following lung cell injury. Because it was theorized that lung wounding and repair are involved in the pathogenesis of acute respiratory distress syndrome (ARDS) and idiopathic pulmonary fibrosis (IPF), in this review, we summarized the experimental evidence of lung cell injury in these two devastating syndromes and discuss relevant genetic, physical, and biological injury mechanisms, as well as mechanisms used by lung cells for cell survival and membrane repair. Finally, we discuss relevant signaling pathways that may be activated by chronic or repeated lung cell injury as an extension of our cell injury and repair focus in this review. We hope that a holistic view of injurious stimuli relevant for ARDS and IPF could lead to updated experimental models. In addition, parallel discussion of membrane repair mechanisms in lung cells and injury-activated signaling pathways would encourage research to bridge gaps in current knowledge. Indeed, deep understanding of lung cell wounding and repair, and discovery of relevant repair moieties for lung cells, should inspire the development of new therapies that are likely preventive and broadly effective for targeting injurious pulmonary diseases.
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Affiliation(s)
- Xiaofei Cong
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
| | - Rolf D Hubmayr
- Emerius, Thoracic Diseases Research Unit, Mayo Clinic, Rochester, Minnesota; and
| | - Changgong Li
- Department of Pediatrics, University of Southern California, Los Angeles, California
| | - Xiaoli Zhao
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia;
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23
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Hegde S, Zimmermann M, Flöck M, Brunthaler R, Spergser J, Rosengarten R, Chopra-Dewasthaly R. Genetic loci of Mycoplasma agalactiae involved in systemic spreading during experimental intramammary infection of sheep. Vet Res 2016; 47:106. [PMID: 27765069 PMCID: PMC5073455 DOI: 10.1186/s13567-016-0387-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/19/2016] [Indexed: 12/17/2022] Open
Abstract
Mycoplasmas are amongst the most successful pathogens of both humans and animals yet the molecular basis of mycoplasma pathogenesis is poorly understood. This is partly due to the lack of classical virulence factors and little similarity to common bacterial pathogenic determinants. Using Mycoplasma agalactiae as a model we initiated research in this direction by screening a transposon mutant library in the natural sheep host using a negative selection method. Having successfully identified putative factors involved in the colonization of local infection and lymphogenic sites, the current study assessed mutants unable to spread systemically in sheep after experimental intramammary infection. Analysis of distant body sites for complete absence of mutants via SSM PCR revealed that additional set of genes, such as pdhB, oppC, oppB, gtsB, MAG1890, MAG5520 and MAG3650 are required for systemic spreading apart from those that were necessary for initial colonization. Additional in vitro studies with the mutants absent at these systemic sites confirmed the potential role of some of the respective gene products concerning their interaction with host cells. Mutants of pdhB, oppC and MAG4460 exhibited significantly slower growth in the presence of HeLa cells in MEM medium. This first attempt to identify genes exclusively required for systemic spreading provides a basis for further in-depth research to understand the exact mechanism of chronicity and persistence of M. agalactiae.
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Affiliation(s)
- Shivanand Hegde
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria.,Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Martina Zimmermann
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Martina Flöck
- Clinic for Ruminants, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Rene Brunthaler
- Institute of Pathology and Forensic Veterinary Medicine, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Joachim Spergser
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Renate Rosengarten
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Rohini Chopra-Dewasthaly
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria.
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24
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Kaiser SJ, Mutters NT, DeRosa A, Ewers C, Frank U, Günther F. Determinants for persistence of Pseudomonas aeruginosa in hospitals: interplay between resistance, virulence and biofilm formation. Eur J Clin Microbiol Infect Dis 2016; 36:243-253. [PMID: 27734161 DOI: 10.1007/s10096-016-2792-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 09/14/2016] [Indexed: 12/27/2022]
Abstract
Pseudomonas aeruginosa (Pa) is one of the major bacterial pathogens causing nosocomial infections. During the past few decades, multidrug-resistant (MDR) and extensively drug-resistant (XDR) lineages of Pa have emerged in hospital settings with increasing numbers. However, it remains unclear which determinants of Pa facilitated this spread. A total of 211 clinical XDR and 38 susceptible clinical Pa isolates (nonXDR), as well as 47 environmental isolates (EI), were collected at the Heidelberg University Hospital. We used RAPD PCR to identify genetic clusters. Carriage of carbapenamases (CPM) and virulence genes were analyzed by PCR, biofilm formation capacity was assessed, in vitro fitness was evaluated using competitive growth assays, and interaction with the host's immune system was analyzed using serum killing and neutrophil killing assays. XDR isolates showed significantly elevated biofilm formation (p < 0.05) and higher competitive fitness compared to nonXDR and EI isolates. Thirty percent (62/205) of the XDR isolates carried a CPM. Similarities in distribution of virulence factors, as well as biofilm formation properties, between CPM+ Pa isolates and EI and between CPM- and nonXDR isolates were detected. Molecular typing revealed two distinct genetic clusters within the XDR population, which were characterized by even higher biofilm formation. In contrast, XDR isolates were more susceptible to the immune response than nonXDR isolates. Our study provides evidence that the ability to form biofilms is an outstanding determinant for persistence and endemic spread of Pa in the hospital setting.
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Affiliation(s)
- S J Kaiser
- Department of Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - N T Mutters
- Department of Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - A DeRosa
- Department of Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - C Ewers
- Institute of Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, Giessen, Germany
| | - U Frank
- Department of Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - F Günther
- Department of Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.
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25
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Kamei A, Gao G, Neale G, Loh LN, Vogel P, Thomas PG, Tuomanen EI, Murray PJ. Exogenous remodeling of lung resident macrophages protects against infectious consequences of bone marrow-suppressive chemotherapy. Proc Natl Acad Sci U S A 2016; 113:E6153-E6161. [PMID: 27671632 PMCID: PMC5068317 DOI: 10.1073/pnas.1607787113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Infection is the single greatest threat to survival during cancer chemotherapy because of depletion of bone marrow-derived immune cells. Phagocytes, especially neutrophils, are key effectors in immunity to extracellular pathogens, which has limited the development of new approaches to protect patients with cancer and chemotherapy-induced neutropenia. Using a model of vaccine-induced protection against lethal Pseudomonas aeruginosa pneumonia in the setting of chemotherapy-induced neutropenia, we found a population of resident lung macrophages in the immunized lung that mediated protection in the absence of neutrophils, bone marrow-derived monocytes, or antibodies. These vaccine-induced macrophages (ViMs) expanded after immunization, locally proliferated, and were closely related to alveolar macrophages (AMs) by surface phenotype and gene expression profiles. By contrast to AMs, numbers of ViMs were stable through chemotherapy, showed enhanced phagocytic activity, and prolonged survival of neutropenic mice from lethal P. aeruginosa pneumonia upon intratracheal adoptive transfer. Thus, induction of ViMs by tissue macrophage remodeling may become a framework for new strategies to activate immune-mediated reserves against infection in immunocompromised hosts.
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Affiliation(s)
- Akinobu Kamei
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105; Department of Pediatrics, Keio University School of Medicine, Tokyo 160-8582, Japan;
| | - Geli Gao
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Geoffrey Neale
- Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Lip Nam Loh
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Peter Vogel
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Paul G Thomas
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Elaine I Tuomanen
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Peter J Murray
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105; Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
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26
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Agnello M, Finkel SE, Wong-Beringer A. Fitness Cost of Fluoroquinolone Resistance in Clinical Isolates of Pseudomonas aeruginosa Differs by Type III Secretion Genotype. Front Microbiol 2016; 7:1591. [PMID: 27757111 PMCID: PMC5047889 DOI: 10.3389/fmicb.2016.01591] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 09/22/2016] [Indexed: 12/23/2022] Open
Abstract
Fluoroquinolone (FQ) resistance is highly prevalent among clinical strains of Pseudomonas aeruginosa, limiting treatment options. We have reported previously that highly virulent strains containing the exoU gene of the type III secretion system are more likely to be FQ-resistant than strains containing the exoS gene, as well as more likely to acquire resistance-conferring mutations in gyrA/B and parC/E. We hypothesize that FQ-resistance imposes a lower fitness cost on exoU compared to exoS strains, thus allowing for better adaptation to the FQ-rich clinical environment. We created isogenic mutants containing a common FQ-resistance conferring point mutation in parC from three exoU to three exoS clinical isolates and tested fitness in vitro using head-to-head competition assays. The mutation differentially affected fitness in the exoU and exoS strains tested. While the addition of the parC mutation dramatically increased fitness in one of the exoU strains leaving the other two unaffected, all three exoS strains displayed a general decrease in fitness. In addition, we found that exoU strains may be able to compensate for the fitness costs associated with the mutation through better regulation of supercoiling compared to the exoS strains. These results may provide a biological explanation for the observed predominance of the virulent exoU genotype in FQ-resistant clinical subpopulations and represent the first investigation into potential differences in fitness costs of FQ-resistance that are linked to the virulence genotype of P. aeruginosa. Understanding the fitness costs of antibiotic resistance and possibilities of compensation for these costs is essential for the rational development of strategies to combat the problem of antibiotic resistance.
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Affiliation(s)
- Melissa Agnello
- School of Pharmacy, University of Southern California Los Angeles, CA, USA
| | - Steven E Finkel
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California Los Angeles, CA, USA
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27
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Colmer-Hamood JA, Dzvova N, Kruczek C, Hamood AN. In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 142:151-91. [PMID: 27571695 DOI: 10.1016/bs.pmbts.2016.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections.
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Affiliation(s)
- J A Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
| | - N Dzvova
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - C Kruczek
- Honors College, Texas Tech University, Lubbock, TX, United States
| | - A N Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
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28
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Bridge DR, Whitmire JM, Makobongo MO, Merrell DS. Heterologous Pseudomonas aeruginosa O-antigen delivery using a Salmonella enterica serovar Typhimurium wecA mutant strain. Int J Med Microbiol 2016; 306:529-540. [PMID: 27476047 DOI: 10.1016/j.ijmm.2016.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 06/22/2016] [Accepted: 06/27/2016] [Indexed: 01/30/2023] Open
Abstract
There is a broad interest in adapting live vaccine strains (LVS) for use as recombinant vaccines that can deliver heterologous antigens. The Salmonella enterica serovar Typhimurium SL1344 ΔwecA LVS contains a mutation in wecA that abrogates production of Enterobacterial common antigen. This ΔwecA strain is attenuated in vivo, persistently colonizes the host, and protects against both wild type and cross-Salmonella serovar lethal challenge in a murine model of salmonellosis. Given these characteristics, we hypothesized that the SL1344 ΔwecA strain could be used as a carrier for heterologous antigen expression. To test this hypothesis, SL1344 ΔwecA was engineered to express the Pseudomonas aeruginosa O11 O-antigen gene cluster. Intraperitoneal (IP) but not oral immunization of BALB/c mice with the heterologous expression strain protected against lethal P. aeruginosa intranasal (IN) challenge. Furthermore, IP immunization resulted in P. aeruginosa O11-specific Ig and IgG antibody production. Functional analysis of sera collected from the IP immunized mice showed antibody-mediated agglutination and opsonophagocytic activity against P. aeruginosa. En masse, these results indicate that the S. Typhimurium SL1344 ΔwecA strain expressing the P. aeruginosa O11 O-antigen gene cluster is able to induce a humoral immune response and to protect against lethal P. aeruginosa challenge. As such, the S. Typhimurium SL1344 ΔwecA LVS can likely serve as a vehicle for expression of a wide variety of heterologous antigens as a means to create recombinant vaccines.
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Affiliation(s)
- Dacie R Bridge
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, United States.
| | - Jeannette M Whitmire
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, United States.
| | - Morris O Makobongo
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, United States.
| | - D Scott Merrell
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, United States.
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29
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Abstract
Bacterial sphingomyelinases and phospholipases are a heterogeneous group of esterases which are usually surface associated or secreted by a wide variety of Gram-positive and Gram-negative bacteria. These enzymes hydrolyze sphingomyelin and glycerophospholipids, respectively, generating products identical to the ones produced by eukaryotic enzymes which play crucial roles in distinct physiological processes, including membrane dynamics, cellular signaling, migration, growth, and death. Several bacterial sphingomyelinases and phospholipases are essential for virulence of extracellular, facultative, or obligate intracellular pathogens, as these enzymes contribute to phagosomal escape or phagosomal maturation avoidance, favoring tissue colonization, infection establishment and progression, or immune response evasion. This work presents a classification proposal for bacterial sphingomyelinases and phospholipases that considers not only their enzymatic activities but also their structural aspects. An overview of the main physiopathological activities is provided for each enzyme type, as are examples in which inactivation of a sphingomyelinase- or a phospholipase-encoding gene impairs the virulence of a pathogen. The identification of sphingomyelinases and phospholipases important for bacterial pathogenesis and the development of inhibitors for these enzymes could generate candidate vaccines and therapeutic agents, which will diminish the impacts of the associated human and animal diseases.
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30
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Mosquera-Rendón J, Rada-Bravo AM, Cárdenas-Brito S, Corredor M, Restrepo-Pineda E, Benítez-Páez A. Pangenome-wide and molecular evolution analyses of the Pseudomonas aeruginosa species. BMC Genomics 2016; 17:45. [PMID: 26754847 PMCID: PMC4710005 DOI: 10.1186/s12864-016-2364-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 01/05/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Drug treatments and vaccine designs against the opportunistic human pathogen Pseudomonas aeruginosa have multiple issues, all associated with the diverse genetic traits present in this pathogen, ranging from multi-drug resistant genes to the molecular machinery for the biosynthesis of biofilms. Several candidate vaccines against P. aeruginosa have been developed, which target the outer membrane proteins; however, major issues arise when attempting to establish complete protection against this pathogen due to its presumably genotypic variation at the strain level. To shed light on this concern, we proposed this study to assess the P. aeruginosa pangenome and its molecular evolution across multiple strains. RESULTS The P. aeruginosa pangenome was estimated to contain more than 16,000 non-redundant genes, and approximately 15 % of these constituted the core genome. Functional analyses of the accessory genome indicated a wide presence of genetic elements directly associated with pathogenicity. An in-depth molecular evolution analysis revealed the full landscape of selection forces acting on the P. aeruginosa pangenome, in which purifying selection drives evolution in the genome of this human pathogen. We also detected distinctive positive selection in a wide variety of outer membrane proteins, with the data supporting the concept of substantial genetic variation in proteins probably recognized as antigens. Approaching the evolutionary information of genes under extremely positive selection, we designed a new Multi-Locus Sequencing Typing assay for an informative, rapid, and cost-effective genotyping of P. aeruginosa clinical isolates. CONCLUSIONS We report the unprecedented pangenome characterization of P. aeruginosa on a large scale, which included almost 200 bacterial genomes from one single species and a molecular evolutionary analysis at the pangenome scale. Evolutionary information presented here provides a clear explanation of the issues associated with the use of protein conjugates from pili, flagella, or secretion systems as antigens for vaccine design, which exhibit high genetic variation in terms of non-synonymous substitutions in P. aeruginosa strains.
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Affiliation(s)
- Jeanneth Mosquera-Rendón
- Bioinformatics Analysis Group-GABi, Centro de Investigación y Desarrollo en Biotecnología-CIDBIO, 111221, Bogotá DC, Colombia. .,Grupo GEBIOMIC, FCEN, Universidad de Antioquia, Medellín, Colombia.
| | - Ana M Rada-Bravo
- Grupo Bacterias y Cáncer, Universidad de Antioquia, Medellín, Colombia. .,Grupo Biociencias, Institución Universitaria Colegio Mayor de Antioquia, Medellín, Colombia.
| | - Sonia Cárdenas-Brito
- Bioinformatics Analysis Group-GABi, Centro de Investigación y Desarrollo en Biotecnología-CIDBIO, 111221, Bogotá DC, Colombia.
| | | | | | - Alfonso Benítez-Páez
- Bioinformatics Analysis Group-GABi, Centro de Investigación y Desarrollo en Biotecnología-CIDBIO, 111221, Bogotá DC, Colombia. .,Centro de Investigación y Desarrollo en Biotecnología, Calle 64A # 52-53 Int8 Of203, 111221, Bogotá DC, Colombia. .,Microbial Ecology, Nutrition & Health Research Unit, Agrochemistry and Food Technology Institute (IATA-CSIC), 46980, Paterna-Valencia, Spain.
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Lopez-Medina E, Fan D, Coughlin LA, Ho EX, Lamont IL, Reimmann C, Hooper LV, Koh AY. Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis. PLoS Pathog 2015; 11:e1005129. [PMID: 26313907 PMCID: PMC4552174 DOI: 10.1371/journal.ppat.1005129] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/04/2015] [Indexed: 01/09/2023] Open
Abstract
Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa’s ability to colonize the GI tract but does decrease P. aeruginosa’s cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease. Pseudomonas aeruginosa and Candida albicans are two medically important human pathogens that often co-infect or co-colonize the same human niches, such as the gut. In a normal healthy host, P. aeruginosa and C. albicans can colonize the gut without any significant pathologic sequelae. But in immunocompromised hosts, both pathogens can escape the gut and cause life-threatening disseminated infections. Yet the mechanisms and pathogenic consequences of interactions between these two pathogens within a living mammalian host are not well understood. Here, we use a mouse model of P. aeruginosa and C. albicans gut co-infection to better understand the mechanisms by which C. albicans inhibits P. aeruginosa infection. C. albicans inhibits the expression of P. aeruginosa genes that are vital for iron acquisition. Accordingly, deleting these iron acquisition genes in P. aeruginosa prevents infection. Understanding how microbes interact and antagonize each other may help us identify new potential therapeutic targets for preventing or treating infections.
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Affiliation(s)
- Eduardo Lopez-Medina
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Di Fan
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Laura A. Coughlin
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Evi X. Ho
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Iain L. Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Cornelia Reimmann
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Lora V. Hooper
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- The Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Center for Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Andrew Y. Koh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail:
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Fu L, He Y, Xu F, Ma Q, Wang F, Xu J. Characterization of a novel thermostable patatin-like protein from a Guaymas basin metagenomic library. Extremophiles 2015; 19:829-40. [DOI: 10.1007/s00792-015-0758-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 05/10/2015] [Indexed: 10/23/2022]
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Sawa T, Shimizu M, Moriyama K, Wiener-Kronish JP. Association between Pseudomonas aeruginosa type III secretion, antibiotic resistance, and clinical outcome: a review. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:668. [PMID: 25672496 PMCID: PMC4331484 DOI: 10.1186/s13054-014-0668-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pseudomonas aeruginosa uses a complex type III secretion system to inject the toxins ExoS, ExoT, ExoU, and ExoY into the cytosol of target eukaryotic cells. This system is regulated by the exoenzyme S regulon and includes the transcriptional activator ExsA. Of the four toxins, ExoU is characterized as the major virulence factor responsible for alveolar epithelial injury in patients with P. aeruginosa pneumonia. Virulent strains of P. aeruginosa possess the exoU gene, whereas non-virulent strains lack this particular gene. The mechanism of virulence for the exoU+ genotype relies on the presence of a pathogenic gene cluster (PAPI-2) encoding exoU and its chaperone, spcU. The ExoU toxin has a patatin-like phospholipase domain in its N-terminal, exhibits phospholipase A2 activity, and requires a eukaryotic cell factor for activation. The C-terminal of ExoU has a ubiquitinylation mechanism of activation. This probably induces a structural change in enzymatic active sites required for phospholipase A2 activity. In P. aeruginosa clinical isolates, the exoU+ genotype correlates with a fluoroquinolone resistance phenotype. Additionally, poor clinical outcomes have been observed in patients with pneumonia caused by exoU+-fluoroquinolone-resistant isolates. Therefore, the potential exists to improve clinical outcomes in patients with P. aeruginosa pneumonia by identifying virulent and antimicrobial drug-resistant strains through exoU genotyping or ExoU protein phenotyping or both.
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Zhang J, Chu Y, Wang P, Ji X, Li X, Wang C, Peng Y. Clinical Outcomes of Multidrug Resistant Pseudomonas aeruginosa Infection and the Relationship With Type III Secretion System in Patients With Diabetic Foot. INT J LOW EXTR WOUND 2014; 13:205-10. [DOI: 10.1177/1534734614545878] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The objective was to analyze the clinical outcomes of multidrug resistant Pseudomonas aeruginosa (MDRPA) infection and determine the relationship between type III secretion system (TTSS) and MDRPA in diabetic foot (DF) patients. A total of 117 patients infected with P aeruginosa were recruited and grouped into MDRPA and non-MDRPA group according to antimicrobial susceptibility testing. TTSS genes were detected by polymerase chain reaction (PCR). Potential risk factors for MDRPA infection were examined using univariate and multivariate analyses. Clinical outcomes were compared on the basis of MDRPA or TTSS virulence gene. Previous antibiotic therapy, previous hospitalization and osteomyelitis were associated with MDRPA infection. MDRPA group had a higher amputation/toe rate (32.6% vs 16.2%) and lower healing rate (20.9% vs 41.9%) than non-MDRPA group ( P = .032). A significantly higher proportion of exoU was present in MDRPA group (75.0% vs 25.0%, P < .05) than non-MDRPA group. Patients infected with exoU isolates had a lower healing rate and higher amputation/toe rate (25.0% vs 65.2%, 33.3% vs 8.7%, P < .05) than infected with exoS isolates. The exoU gene was predominance among MDRPA strains. The poor clinical outcomes of MDRPA infection in patients with DF were attributable to exoU gene.
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Affiliation(s)
- Jinghang Zhang
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, The Key Laboratory of Hormones and Development(Ministry of Health), Department of Diabetic foot, the Metabolic Disease Hospital,Tianjin Institute of Endocrinology,Tianjin Medical University, Tianjin, China
| | - Yuejie Chu
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, The Key Laboratory of Hormones and Development(Ministry of Health), Department of Diabetic foot, the Metabolic Disease Hospital,Tianjin Institute of Endocrinology,Tianjin Medical University, Tianjin, China
| | - Penghua Wang
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, The Key Laboratory of Hormones and Development(Ministry of Health), Department of Diabetic foot, the Metabolic Disease Hospital,Tianjin Institute of Endocrinology,Tianjin Medical University, Tianjin, China
| | - Xiaoyan Ji
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, The Key Laboratory of Hormones and Development(Ministry of Health), Department of Diabetic foot, the Metabolic Disease Hospital,Tianjin Institute of Endocrinology,Tianjin Medical University, Tianjin, China
| | - Xiwen Li
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, The Key Laboratory of Hormones and Development(Ministry of Health), Department of Diabetic foot, the Metabolic Disease Hospital,Tianjin Institute of Endocrinology,Tianjin Medical University, Tianjin, China
| | - Chao Wang
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, The Key Laboratory of Hormones and Development(Ministry of Health), Department of Diabetic foot, the Metabolic Disease Hospital,Tianjin Institute of Endocrinology,Tianjin Medical University, Tianjin, China
| | - Yue Peng
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, The Key Laboratory of Hormones and Development(Ministry of Health), Department of Diabetic foot, the Metabolic Disease Hospital,Tianjin Institute of Endocrinology,Tianjin Medical University, Tianjin, China
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Sato H, Frank DW. Intoxication of host cells by the T3SS phospholipase ExoU: PI(4,5)P2-associated, cytoskeletal collapse and late phase membrane blebbing. PLoS One 2014; 9:e103127. [PMID: 25061861 PMCID: PMC4111512 DOI: 10.1371/journal.pone.0103127] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 06/27/2014] [Indexed: 01/09/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is associated with hospital-acquired infections, ventilator-associated pneumonia, and morbidity of immunocompromised individuals. A subpopulation of P. aeruginosa encodes a protein, ExoU, which exhibits acute cytotoxicity. Toxicity is directly related to the phospholipase A2 activity of the protein after injection into the host cytoplasm via a type III secretion system. ExoU enzymatic activity requires eukaryotic cofactors, ubiquitin or ubiquitin-modified proteins. When administered extracellularly, ExoU is unable to intoxicate epithelial cells in culture, even in the presence of the cofactor. Injection or transfection of ExoU is necessary to observe the acute cytotoxic response. Biochemical approaches indicate that ExoU possesses high affinity to a multifunctional phosphoinositide, phosphatidylinositol 4,5-bisphosphate or PI(4,5)P2 and that it is capable of utilizing this phospholipid as a substrate. In eukaryotic cells, PI(4,5)P2 is mainly located in the cytoplasmic side of the plasma membrane and anchors adaptor proteins that are involved in cytoskeletal structures, focal adhesions, and plasma membranes. Time-lapse fluorescent microscopy analyses of infected live cells demonstrate that ExoU intoxication correlates with intracellular damage in the early phases of infection, such as disruption of focal adhesions, cytoskeletal collapse, actin depolymerization, and cell rounding. At later time points, a membrane blebbing phenotype was prominent prior to the loss of the plasma membrane integrity and barrier function. Membrane blebbing appears to accelerate membrane rupture and the release of intracellular markers. Our data suggest that in eukaryotic host cells, intracellular ExoU targets and hydrolyzes PI(4,5)P2 on the plasma membrane, causing a subsequent disruption of cellular structures and membrane integrity.
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Affiliation(s)
- Hiromi Sato
- Center for Infectious Disease Research, Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
| | - Dara W. Frank
- Center for Infectious Disease Research, Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
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Pereira SG, Rosa AC, Ferreira AS, Moreira LM, Proença DN, Morais PV, Cardoso O. Virulence factors and infection ability of Pseudomonas aeruginosa isolates from a hydropathic facility and respiratory infections. J Appl Microbiol 2014; 116:1359-68. [PMID: 24484457 DOI: 10.1111/jam.12463] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 01/17/2014] [Accepted: 01/27/2014] [Indexed: 11/27/2022]
Abstract
AIMS To compare the virulence pool and acute infection ability of Pseudomonas aeruginosa isolates from a hydropathic facility, used to treat respiratory conditions by inhalation of untreated natural mineral water, with clinical isolates from respiratory infections. METHODS AND RESULTS Pseudomonas aeruginosa isolates from a hydropathic facility and from respiratory infections were typed by pulsed-field gel electrophoresis. Nonclonal representatives of each population were selected. 18 virulence-encoding genes were screened by polymerase chain reaction and statistically compared by multiple correspondence analysis. Homogeneous distribution of genes between populations but higher genetic association in aquatic isolates was observed, as well as distinct virulence pool according to location in the water system. Acute infection ability of selected isolates from each population, in Galleria mellonella model, showed lower LD50 of the majority of the hydropathic isolates and significant variations in LD50 of biofilm isolates from different equipments. CONCLUSIONS Hydrotherapy Ps. aeruginosa isolates present similar virulence to isolates from respiratory infections. Hydrotherapy users may be exposed to different microbiological risks when using different treatment equipments. SIGNIFICANCE AND IMPACT OF THE STUDY Twenty-one million people use hydropathic facilities in Europe, and the majority present risk factors to pneumonia. This study demonstrates the health risk associated with this practice. Revision of European regulations should be considered.
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Affiliation(s)
- S G Pereira
- Center for Pharmaceutical Studies, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
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Sullivan E, Bensman J, Lou M, Agnello M, Shriner K, Wong-Beringer A. Risk of developing pneumonia is enhanced by the combined traits of fluoroquinolone resistance and type III secretion virulence in respiratory isolates of Pseudomonas aeruginosa. Crit Care Med 2014; 42:48-56. [PMID: 23963124 DOI: 10.1097/ccm.0b013e318298a86f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To determine the differential association of host characteristics, antimicrobial resistance, and type III secretion system virulence of Pseudomonas aeruginosa isolates with respiratory syndromes in hospitalized adult patients. DESIGN Retrospective, cohort study. SETTING Community teaching hospital. PATIENTS Two hundred eighteen consecutive adult patients with respiratory culture positive for P. aeruginosa between January 2005 to January 2010. INTERVENTIONS Medical charts were reviewed to obtain demographic, laboratory, radiographic, and clinical information. Isolates were assayed by polymerase chain reaction for genes encoding the type III secretion system effectors (ExoU, ExoS, and PcrV) and for strain relatedness using randomly amplified polymorphic DNA analysis. Levofloxacin susceptibility was determined by broth microdilution. Patients were grouped by colonization, bronchitis, or pneumonia and were compared for differential risk of developing the clinical syndrome with respect to host and microbial characteristics. MEASUREMENTS AND MAIN RESULTS Half of the study cohort (54%, 117 of 218) had pneumonia, 32% (70 of 218) had bronchitis, and 14% (31 of 218) had colonization; in-hospital mortality was 35%, 11%, and 0%, respectively. Host factors strongly associated with pneumonia development were residence in long-term care facility, healthcare-associated acquisition of P. aeruginosa, higher Acute Physiology and Chronic Health Evaluation II score, presence of enteral feeding tube, mechanical ventilation, and recent history of pneumonia. Fluoroquinolone-resistant (57% vs 34%, 16%; p < 0.0001) and multidrug-resistant (36% vs 26%, 7%; p = 0.0045) strains were more likely to cause pneumonia than bronchitis or colonization, respectively. Analysis of host and microbial factors in a multivariate regression model yielded the combined traits of fluoroquinolone resistance and gene encoding the type III secretion system ExoU effector in P. aeruginosa as the single most significant predictor of pneumonia development. CONCLUSIONS These results suggest that fluoroquinolone-resistant phenotype in a type III secretion system exoU strain background contributes toward the pathogenesis of P. aeruginosa in pneumonia.
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Affiliation(s)
- Eva Sullivan
- 1Huntington Hospital, Pasadena, CA. 2University of Southern California, Los Angeles, CA
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The molecular mechanism of acute lung injury caused by Pseudomonas aeruginosa: from bacterial pathogenesis to host response. J Intensive Care 2014; 2:10. [PMID: 25520826 PMCID: PMC4267601 DOI: 10.1186/2052-0492-2-10] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 01/28/2014] [Indexed: 12/25/2022] Open
Abstract
Pseudomonas aeruginosa is the most common gram-negative pathogen causing pneumonia in immunocompromised patients. Acute lung injury induced by bacterial exoproducts is associated with a poor outcome in P. aeruginosa pneumonia. The major pathogenic toxins among the exoproducts of P. aeruginosa and the mechanism by which they cause acute lung injury have been investigated: exoenzyme S and co-regulated toxins were found to contribute to acute lung injury. P. aeruginosa secretes these toxins through the recently defined type III secretion system (TTSS), by which gram-negative bacteria directly translocate toxins into the cytosol of target eukaryotic cells. TTSS comprises the secretion apparatus (termed the injectisome), translocators, secreted toxins, and regulatory components. In the P. aeruginosa genome, a pathogenic gene cluster, the exoenzyme S regulon, encodes genes underlying the regulation, secretion, and translocation of TTSS. Four type III secretory toxins, namely ExoS, ExoT, ExoU, and ExoY, have been identified in P. aeruginosa. ExoS is a 49-kDa form of exoenzyme S, a bifunctional toxin that exerts ADP-ribosyltransferase and GTPase-activating protein (GAP) activity to disrupt endocytosis, the actin cytoskeleton, and cell proliferation. ExoT, a 53-kDa form of exoenzyme S with 75% sequence homology to ExoS, also exerts GAP activity to interfere with cell morphology and motility. ExoY is a nucleotidal cyclase that increases the intracellular levels of cyclic adenosine and guanosine monophosphates, resulting in edema formation. ExoU, which exhibits phospholipase A2 activity activated by host cell ubiquitination after translocation, is a major pathogenic cytotoxin that causes alveolar epithelial injury and macrophage necrosis. Approximately 20% of clinical isolates also secrete ExoU, a gene encoded within an insertional pathogenic gene cluster named P. aeruginosa pathogenicity island-2. The ExoU secretory phenotype is associated with a poor clinical outcome in P. aeruginosa pneumonia. Blockade of translocation by TTSS or inhibition of the enzymatic activity of translocated toxins has the potential to decrease acute lung injury and improve clinical outcome.
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Allewelt M. Aspiration pneumonia and primary lung abscess: diagnosis and therapy of an aerobic or an anaerobic infection? Expert Rev Respir Med 2014; 1:111-9. [DOI: 10.1586/17476348.1.1.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Azghani AO, Neal K, Idell S, Amaro R, Baker JW, Omri A, Pendurthi UR. Mechanism of fibroblast inflammatory responses to Pseudomonas aeruginosa elastase. MICROBIOLOGY-SGM 2014; 160:547-555. [PMID: 24385476 DOI: 10.1099/mic.0.075325-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Receptor tyrosine kinases, including the epidermal growth factor receptors (EGFR), are able to activate the mitogen-activated protein kinases (MAPK) via several adaptor proteins and protein kinases such as Raf. EGFR can be activated by a variety of extracellular stimuli including neutrophil elastase, but we are aware of no report as to whether Pseudomonas aeruginosa produced elastase (PE) could elicit such signalling through EGFR activation. We sought to test the inference that PE modulates inflammatory responses in human lung fibroblasts and that the process occurs by activation of the EGFR/MAPK pathways. We utilized IL-8 cytokine expression as a pathway-specific end point measure of the fibroblast inflammatory response to PE. Western blot analysis was performed to detect phosphorylation of EGFR and signal transduction intermediates. Northern blot, real-time PCR, and ELISA methods were utilized to determine cytokine gene expression levels. We found that PE induces phosphorylation of the EGFR and the extracellular signal-regulated proteins (ERK1/2) of the MAPK pathway, and nuclear translocation of NF-κB. Furthermore, enzymically active PE enhances IL-8 mRNA and protein secretion. Pretreatment of the cells with specific inhibitors of EGFR, MAPK kinase and NF-κB markedly attenuated the PE-induced signal proteins phosphorylation and IL-8 gene expression and protein secretion. Collectively, the data show that PE produced by Pseudomonas aeruginosa can modulate lung inflammation by exploiting the EGFR/ERK signalling cascades and enhancing IL-8 production in the lungs via NF-κB activation.
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Affiliation(s)
- Ali O Azghani
- Department of Biology, University of Texas at Tyler, Tyler, TX, USA
| | - Kourtney Neal
- Department of Biology, University of Texas at Tyler, Tyler, TX, USA
| | - Steven Idell
- Department of Cellular and Molecular Biology and Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, TX, USA
| | - Rodolfo Amaro
- Department of Pediatric Pulmonology, University of Texas Health Science Center at Tyler, Tyler, TX, USA
| | - Jason W Baker
- Program in Environmental and Earth Sciences, University of Texas at Arlington, Arlington, TX, USA
| | - Abdelwahab Omri
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, Canada
| | - Usha R Pendurthi
- Department of Cellular and Molecular Biology and Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, TX, USA
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Rolsma SL, Frank DW. In vitro assays to monitor the activity of Pseudomonas aeruginosa Type III secreted proteins. Methods Mol Biol 2014; 1149:171-84. [PMID: 24818904 PMCID: PMC5860653 DOI: 10.1007/978-1-4939-0473-0_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pseudomonas aeruginosa secretes numerous toxins and destructive enzymes that play distinct roles in pathogenesis. The Type III secretion system (T3SS) of Pseudomonas is a system that delivers a subset of toxins directly into the cytoplasm of eukaryotic cells. The secreted effectors include ExoS, ExoT, ExoU, and ExoY. In this chapter, we describe methods to induce T3S expression and measure the enzymatic activities of each effector in in vitro assays. ExoU is a phospholipase and its activity can be measured in a fluorescence-based assay monitoring the cleavage of the fluorogenic substrate, PED6. ExoS and ExoT both possess ADP-ribosyltransferase (ADPRT) and GTPase-activating protein (GAP) activity. ADPRT activity can be assessed by using radiolabeled nicotinamide adenine dinucleotide (NAD(+)) and measuring the covalent incorporation of ADP-ribose into a target protein. GAP activity is measured by the release of radiolabeled phosphate from [γ-(32)P]GTP-bound target proteins. In accordance with recent trends towards reducing the use of radioactivity in the laboratory, alternative assays using fluorescent or biotin-labeled reagents are described. ExoY is a nucleotidyl cyclase; cAMP production stimulated by ExoY can be monitored using reverse-phase HPLC or with commercially available immunological assays.
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Affiliation(s)
- Stephanie L Rolsma
- Department of Microbiology and Molecular Genetics, Center of Infectious Disease Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
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van de Weert – van Leeuwen PB, de Vrankrijker AMM, Fentz J, Ciofu O, Wojtaszewski JFP, Arets HGM, Hulzebos HJ, van der Ent CK, Beekman JM, Johansen HK. Effect of long-term voluntary exercise wheel running on susceptibility to bacterial pulmonary infections in a mouse model. PLoS One 2013; 8:e82869. [PMID: 24376599 PMCID: PMC3871638 DOI: 10.1371/journal.pone.0082869] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 11/06/2013] [Indexed: 12/29/2022] Open
Abstract
Regular moderate exercise has been suggested to exert anti-inflammatory effects and improve immune effector functions, resulting in reduced disease incidence and viral infection susceptibility. Whether regular exercise also affects bacterial infection susceptibility is unknown. The aim of this study was to investigate whether regular voluntary exercise wheel running prior to a pulmonary infection with bacteria (P. aeruginosa) affects lung bacteriology, sickness severity and phagocyte immune function in mice. Balb/c mice were randomly placed in a cage with or without a running wheel. After 28 days, mice were intranasally infected with P. aeruginosa. Our study showed that regular exercise resulted in a higher sickness severity score and bacterial (P. aeruginosa) loads in the lungs. The phagocytic capacity of monocytes and neutrophils from spleen and lungs was not affected. Although regular moderate exercise has many health benefits, healthy mice showed increased bacterial (P. aeruginosa) load and symptoms, after regular voluntary exercise, with perseverance of the phagocytic capacity of monocytes and neutrophils. Whether patients, suffering from bacterial infectious diseases, should be encouraged to engage in exercise and physical activities with caution requires further research.
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Affiliation(s)
- Pauline B. van de Weert – van Leeuwen
- Department of Pediatric Pulmonology, University Medical Centre Utrecht, Utrecht, The Netherlands
- Department of Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
- Centre for Molecular and Cellular Intervention, University Medical Centre Utrecht, Utrecht, The Netherlands
- * E-mail:
| | | | - Joachim Fentz
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Oana Ciofu
- Department of International Health, Immunology and Microbiology, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F. P. Wojtaszewski
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Hubertus G. M. Arets
- Department of Pediatric Pulmonology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Hendrikus J. Hulzebos
- Child Development & Exercise Centre, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Cornelis K. van der Ent
- Department of Pediatric Pulmonology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Jeffrey M. Beekman
- Department of Pediatric Pulmonology, University Medical Centre Utrecht, Utrecht, The Netherlands
- Department of Translational Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
- Centre for Molecular and Cellular Intervention, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Helle K. Johansen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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Exploitation of eukaryotic subcellular targeting mechanisms by bacterial effectors. Nat Rev Microbiol 2013; 11:316-26. [PMID: 23588250 DOI: 10.1038/nrmicro3009] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Several bacterial species have evolved specialized secretion systems to deliver bacterial effector proteins into eukaryotic cells. These effectors have the capacity to modulate host cell pathways in order to promote bacterial survival and replication. The spatial and temporal context in which the effectors exert their biochemical activities is crucial for their function. To fully understand effector function in the context of infection, we need to understand the mechanisms that lead to the precise subcellular localization of effectors following their delivery into host cells. Recent studies have shown that bacterial effectors exploit host cell machinery to accurately target their biochemical activities within the host cell.
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Schuster M, Sexton DJ, Diggle SP, Greenberg EP. Acyl-homoserine lactone quorum sensing: from evolution to application. Annu Rev Microbiol 2013; 67:43-63. [PMID: 23682605 DOI: 10.1146/annurev-micro-092412-155635] [Citation(s) in RCA: 380] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Quorum sensing (QS) is a widespread process in bacteria that employs autoinducing chemical signals to coordinate diverse, often cooperative activities such as bioluminescence, biofilm formation, and exoenzyme secretion. Signaling via acyl-homoserine lactones is the paradigm for QS in Proteobacteria and is particularly well understood in the opportunistic pathogen Pseudomonas aeruginosa. Despite thirty years of mechanistic research, empirical studies have only recently addressed the benefits of QS and provided support for the traditional assumptions regarding its social nature and its role in optimizing cell-density-dependent group behaviors. QS-controlled public-goods production has served to investigate principles that explain the evolution and stability of cooperation, including kin selection, pleiotropic constraints, and metabolic prudence. With respect to medical application, appreciating social dynamics is pertinent to understanding the efficacy of QS-inhibiting drugs and the evolution of resistance. Future work will provide additional insight into the foundational assumptions of QS and relate laboratory discoveries to natural ecosystems.
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Affiliation(s)
- Martin Schuster
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331; ,
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Djonović S, Urbach JM, Drenkard E, Bush J, Feinbaum R, Ausubel JL, Traficante D, Risech M, Kocks C, Fischbach MA, Priebe GP, Ausubel FM. Trehalose biosynthesis promotes Pseudomonas aeruginosa pathogenicity in plants. PLoS Pathog 2013; 9:e1003217. [PMID: 23505373 PMCID: PMC3591346 DOI: 10.1371/journal.ppat.1003217] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 01/13/2013] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa strain PA14 is a multi-host pathogen that infects plants, nematodes, insects, and vertebrates. Many PA14 factors are required for virulence in more than one of these hosts. Noting that plants have a fundamentally different cellular architecture from animals, we sought to identify PA14 factors that are specifically required for plant pathogenesis. We show that synthesis by PA14 of the disaccharide trehalose is required for pathogenesis in Arabidopsis, but not in nematodes, insects, or mice. In-frame deletion of two closely-linked predicted trehalose biosynthetic operons, treYZ and treS, decreased growth in Arabidopsis leaves about 50 fold. Exogenously co-inoculated trehalose, ammonium, or nitrate, but not glucose, sulfate, or phosphate suppressed the phenotype of the double ΔtreYZΔtreS mutant. Exogenous trehalose or ammonium nitrate does not suppress the growth defect of the double ΔtreYZΔtreS mutant by suppressing the plant defense response. Trehalose also does not function intracellularly in P. aeruginosa to ameliorate a variety of stresses, but most likely functions extracellularly, because wild-type PA14 rescued the in vivo growth defect of the ΔtreYZΔtreS in trans. Surprisingly, the growth defect of the double ΔtreYZΔtreS double mutant was suppressed by various Arabidopsis cell wall mutants that affect xyloglucan synthesis, including an xxt1xxt2 double mutant that completely lacks xyloglucan, even though xyloglucan mutants are not more susceptible to pathogens and respond like wild-type plants to immune elicitors. An explanation of our data is that trehalose functions to promote the acquisition of nitrogen-containing nutrients in a process that involves the xyloglucan component of the plant cell wall, thereby allowing P. aeruginosa to replicate in the intercellular spaces in a leaf. This work shows how P. aeruginosa, a multi-host opportunistic pathogen, has repurposed a highly conserved "house-keeping" anabolic pathway (trehalose biosynthesis) as a potent virulence factor that allows it to replicate in the intercellular environment of a leaf.
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Affiliation(s)
- Slavica Djonović
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jonathan M. Urbach
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Eliana Drenkard
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jenifer Bush
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Rhonda Feinbaum
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jonathan L. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - David Traficante
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Martina Risech
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Christine Kocks
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael A. Fischbach
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States of America
| | - Gregory P. Priebe
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts, United States of America
| | - Frederick M. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Spread of multidrug-resistant Pseudomonas aeruginosa clones in a university hospital. J Clin Microbiol 2012; 51:665-8. [PMID: 23241381 DOI: 10.1128/jcm.03071-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
An outbreak of multidrug-resistant Pseudomonas aeruginosa (MDRPA) infections in a university hospital is described. Phenotypic and genotypic analysis of 240 isolates revealed that 152 patients, mainly in the intensive care unit (ICU), were colonized or infected with MDRPA, the majority with O11. All metallo-β-lactamase (MBL)-positive isolates carried the bla(VIM-2) or bla(VIM-1) gene. One or more type III secretion system toxin genes were detected in most isolates. Five dominant pulsed-field gel electrophoresis (PFGE) types were characterized, associated with ST235, ST111, ST253, ST309, and ST639.
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Kamei A, Wu W, Traficante DC, Koh AY, Van Rooijen N, Pier GB, Priebe GP. Collaboration between macrophages and vaccine-induced CD4+ T cells confers protection against lethal Pseudomonas aeruginosa pneumonia during neutropenia. J Infect Dis 2012; 207:39-49. [PMID: 23100569 DOI: 10.1093/infdis/jis657] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The usefulness of vaccine-based strategies to prevent lethal bacterial infection in a host with neutropenia is not well-defined. Here, we show in a neutropenic mouse model that immunity induced by mucosal vaccination with a live-attenuated Pseudomonas aeruginosa vaccine is protective against lethal P. aeruginosa pneumonia caused by both vaccine-homologous and vaccine-heterologous strains, whereas passive immunization confers only vaccine-homologous protection. Cells in the macrophage lineage served as crucial innate cellular effectors in the neutropenic host after active immunization. Vaccine efficacy was CD4(+) T-cell dependent and associated with accumulation of macrophage-lineage cells in the alveolar space after infection, as well as with enhanced P. aeruginosa clearance from the lung. Adaptive CD4(+) T cells produced granulocyte-macrophage colony-stimulating factor (GM-CSF) on restimulation in vitro, and local GM-CSF was critical for vaccine efficacy. Thus, collaboration between the innate and adaptive effectors induced by mucosal vaccination can overcome neutropenia and confer protection against lethal bacterial infection in the profoundly neutropenic host.
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Affiliation(s)
- Akinobu Kamei
- Channing Laboratory, Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA.
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Agnello M, Wong-Beringer A. Differentiation in quinolone resistance by virulence genotype in Pseudomonas aeruginosa. PLoS One 2012; 7:e42973. [PMID: 22905192 PMCID: PMC3414457 DOI: 10.1371/journal.pone.0042973] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 07/16/2012] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa is a leading pathogen that has become increasingly resistant to the fluoroquinolone antibiotics due to widespread prescribing. Adverse outcomes have been shown for patients infected with fluoroquinolone-resistant strains. The type III secretion system (TTSS) is a major virulence determinant during acute infections through the injection of effector toxins into host cells. Most strains exhibit a unique TTSS virulence genotype defined by the presence of either exoS or exoU gene encoding two of the effector toxins, ExoS and ExoU, respectively. Specific TTSS effector genotype has been shown previously to differentially impact virulence in pneumonia. In this study, we examined the relationship between TTSS effector genotype and fluoroquinolone resistance mechanisms in a collection of 270 respiratory isolates. We found that a higher proportion of exoU+ strains were fluoroquinolone-resistant compared to exoS+ strains (63% vs 49%, p = 0.03) despite its lower overall prevalence (38% exoU+ vs 56% exoS+). Results from sequencing the quinolone resistance determining regions (QRDRs) of the 4 target genes (gyrA, gyrB, parC, parE) indicated that strains containing the exoU gene were more likely to acquire ≥2 mutations than exoS+ strains at MICs ≤8 µg/ml (13% vs none) and twice as likely to have mutations in both gyrA and parC than exoS+ strains (48% vs 24% p = 0.0439). Our findings indicate that P. aeruginosa strains differentially develop resistance-conferring mutations that correlate with TTSS effector genotype and the more virulent exoU+ subpopulation. Differences in mutational processes by virulence genotype that were observed suggest co-evolution of resistance and virulence traits favoring a more virulent genotype in the quinolone-rich clinical environment.
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Affiliation(s)
- Melissa Agnello
- School of Pharmacy, University of Southern California, Los Angeles, California, United States of America
| | - Annie Wong-Beringer
- School of Pharmacy, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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Topical neutralization of interleukin-17 during experimental Pseudomonas aeruginosa corneal infection promotes bacterial clearance and reduces pathology. Infect Immun 2012; 80:3706-12. [PMID: 22802348 DOI: 10.1128/iai.00249-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The proinflammatory cytokine interleukin-17 (IL-17) is involved in neutrophilic tissue infiltration, contributing to both microbial clearance as well as inflammation-associated tissue damage. Its role during bacterial corneal infections is unknown. We hypothesized that IL-17 responses would be detrimental in this setting and tested the impact of IL-17 receptor deficiency or antibody-mediated neutralization of IL-17 in a murine model of Pseudomonas aeruginosa ulcerative keratitis after scratch injury. We found that, compared with infected corneas from wild-type mice, those from IL-17 receptor (IL-17R)-deficient mice had significantly lower corneal pathology scores, neutrophil influx, and intracellular bacterial levels. Infected IL-17R-deficient corneas had low intercellular adhesion molecule 1 (ICAM-1) expression, and ICAM-1-deficient mice were similarly resistant to infection. Topical treatment with polyclonal antibodies to IL-17 resulted in significant reductions in corneal pathology and also lowered bacterial counts after infection with six different laboratory or clinical P. aeruginosa strains, including both invasive and cytotoxic strains. Thus, neutralization of IL-17 during P. aeruginosa corneal infection reduces neutrophil influx and pathology without compromising bacterial clearance and offers a promising new avenue for therapy of these potentially sight-threatening infections.
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Wu W, Huang J, Duan B, Traficante DC, Hong H, Risech M, Lory S, Priebe GP. Th17-stimulating protein vaccines confer protection against Pseudomonas aeruginosa pneumonia. Am J Respir Crit Care Med 2012; 186:420-7. [PMID: 22723292 DOI: 10.1164/rccm.201202-0182oc] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
RATIONALE New vaccine approaches are needed for Pseudomonas aeruginosa, which continues to be a major cause of serious pulmonary infections. Although Th17 cells can protect against gram-negative pathogens at mucosal surfaces, including the lung, the bacterial proteins recognized by Th17 cells are largely unknown and could be potential new vaccine candidates. OBJECTIVES We describe a strategy to identify Th17-stimulating protein antigens of Pseudomonas aeruginosa to assess their efficacy as vaccines against pneumonia. METHODS Using a library of in vitro transcribed and translated P. aeruginosa proteins, we screened for Th17-stimulating antigens by coculturing the library proteins with splenocytes from mice immunized with a live-attenuated P. aeruginosa vaccine that is protective via Th17-based immunity. We measured antibody and Th17 responses after intranasal immunization of mice with the purified proteins mixed with the Th17 adjuvant curdlan, and we tested the protective efficacy of vaccination in a murine model of acute pneumonia. MEASUREMENTS AND MAIN RESULTS The proteins PopB, FpvA, FptA, OprL, and PilQ elicited strong IL-17 secretion in the screen, and purified versions of PopB, FpvA, and OprL stimulated high IL-17 production from immune splenocytes. Immunization with PopB, which is a highly conserved component of the type III secretion system and a known virulence factor, elicited Th17 responses and also enhanced clearance of P. aeruginosa from the lung and spleen after challenge. PopB-immunized mice were protected from lethal pneumonia in an antibody-independent, IL-17-dependent manner. CONCLUSIONS Screening for Th17-stimulating protein antigens identified PopB as a novel and promising vaccine candidate for P. aeruginosa.
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Affiliation(s)
- Weihui Wu
- Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115, USA
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