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Seghal Kiran G, Ramasamy P, Sekar S, Ramu M, Hassan S, Ninawe A, Selvin J. Synthetic biology approaches: Towards sustainable exploitation of marine bioactive molecules. Int J Biol Macromol 2018; 112:1278-1288. [DOI: 10.1016/j.ijbiomac.2018.01.149] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 01/18/2018] [Accepted: 01/21/2018] [Indexed: 12/18/2022]
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Nguyen TH, Park MD, Otto M. Host Response to Staphylococcus epidermidis Colonization and Infections. Front Cell Infect Microbiol 2017; 7:90. [PMID: 28377905 PMCID: PMC5359315 DOI: 10.3389/fcimb.2017.00090] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 03/07/2017] [Indexed: 01/11/2023] Open
Abstract
The majority of research in the Staphylococcus field has been dedicated to the understanding of Staphylococcus aureus infections. In contrast, there is limited information on infections by coagulase-negative Staphylococci (CoNS) and how the host responds to them. S. epidermidis, a member of the coagulase-negative Staphylococci, is an important commensal organism of the human skin and mucous membranes; and there is emerging evidence of its benefit for human health in fighting off harmful microorganisms. However, S. epidermidis can cause opportunistic infections, which include particularly biofilm-associated infections on indwelling medical devices. These often can disseminate into the bloodstream; and in fact, S. epidermidis is the most frequent cause of nosocomial sepsis. The increasing use of medical implants and the dramatic shift in the patient demographic population in recent years have contributed significantly to the rise of S. epidermidis infections. Furthermore, treatment has been complicated by the emergence of antibiotic-resistant strains. Today, S. epidermidis is a major nosocomial pathogen posing significant medical and economic burdens. In this review, we present the current understanding of mechanisms of host defense against the prototypical CoNS species S. epidermidis as a commensal of the skin and mucous membranes, and during biofilm-associated infection and sepsis.
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Affiliation(s)
- Thuan H Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health Bethesda, MD, USA
| | - Matthew D Park
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health Bethesda, MD, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health Bethesda, MD, USA
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Al-Ishaq R, Armstrong J, Gregory M, O'Hara M, Phiri K, Harris LG, Rohde H, Siemssen N, Frommelt L, Mack D, Wilkinson TS. Effects of polysaccharide intercellular adhesin (PIA) in an ex vivo model of whole blood killing and in prosthetic joint infection (PJI): A role for C5a. Int J Med Microbiol 2015; 305:948-56. [PMID: 26365169 DOI: 10.1016/j.ijmm.2015.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 08/05/2015] [Accepted: 08/16/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND A major complication of using medical devices is the development of biofilm-associated infection caused by Staphylococcus epidermidis where polysaccharide intercellular adhesin (PIA) is a major mechanism of biofilm accumulation. PIA affects innate and humoral immunity in isolated cells and animal models. Few studies have examined these effects in prosthetic joint infection (PJI). METHODS This study used ex vivo whole blood modelling in controls together with matched-serum and staphylococcal isolates from patients with PJI. RESULTS Whole blood killing of PIA positive S. epidermidis and its isogenic negative mutant was identical. Differences were unmasked in immunosuppressed whole blood pre-treated with dexamethasone where PIA positive bacteria showed a more resistant phenotype. PIA expression was identified in three unique patterns associated with bacteria and leukocytes, implicating a soluble form of PIA. Purified PIA reduced whole blood killing while increasing C5a levels. In clinically relevant staphylococcal isolates and serum samples from PJI patients; firstly complement C5a was increased 3-fold compared to controls; secondly, the C5a levels were significantly higher in serum from PJI patients whose isolates preferentially formed PIA-associated biofilms. CONCLUSIONS These data demonstrate for the first time that the biological effects of PIA are mediated through C5a in patients with PJI.
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Affiliation(s)
- Rand Al-Ishaq
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom
| | - Jayne Armstrong
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom
| | - Martin Gregory
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom
| | - Miriam O'Hara
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom
| | - Kudzai Phiri
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom
| | - Llinos G Harris
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom
| | - Holger Rohde
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Nicolaus Siemssen
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Lars Frommelt
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Dietrich Mack
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom; Bioscientia Labor Ingelheim, Institut für Medizinische Diagnostik GmbH, Mikrobiologie Konrad-Adenauer-Straße 17, 55218 Ingelheim, Germany
| | - Thomas S Wilkinson
- Institute of Life Science, Microbiology and Infectious Disease, Swansea University, First Floor, Room 137, Singleton Park SA2 8PP, United Kingdom.
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Neonatal immune adaptation of the gut and its role during infections. Clin Dev Immunol 2013; 2013:270301. [PMID: 23737810 PMCID: PMC3659470 DOI: 10.1155/2013/270301] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 04/03/2013] [Indexed: 12/22/2022]
Abstract
The intestinal tract is engaged in a relationship with a dense and complex microbial ecosystem, the microbiota. The establishment of this symbiosis is essential for host physiology, metabolism, and immune homeostasis. Because newborns are essentially sterile, the first exposure to microorganisms and environmental endotoxins during the neonatal period is followed by a crucial sequence of active events leading to immune tolerance and homeostasis. Contact with potent immunostimulatory molecules starts immediately at birth, and the discrimination between commensal bacteria and invading pathogens is essential to avoid an inappropriate immune stimulation and/or host infection. The dysregulation of these tight interactions between host and microbiota can be responsible for important health disorders, including inflammation and sepsis. This review summarizes the molecular events leading to the establishment of postnatal immune tolerance and how pathogens can avoid host immunity and induce neonatal infections and sepsis.
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