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Hoffman A, Nizet V. The Prospect of Biomimetic Immune Cell Membrane-Coated Nanomedicines for Treatment of Serious Bacterial Infections and Sepsis. J Pharmacol Exp Ther 2024; 389:289-300. [PMID: 38580449 PMCID: PMC11125797 DOI: 10.1124/jpet.123.002095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 02/17/2024] [Accepted: 03/07/2024] [Indexed: 04/07/2024] Open
Abstract
Invasive bacterial infections and sepsis are persistent global health concerns, complicated further by the escalating threat of antibiotic resistance. Over the past 40 years, collaborative endeavors to improve the diagnosis and critical care of septic patients have improved outcomes, yet grappling with the intricate immune dysfunction underlying the septic condition remains a formidable challenge. Anti-inflammatory interventions that exhibited promise in murine models failed to manifest consistent survival benefits in clinical studies through recent decades. Novel therapeutic approaches that target bacterial virulence factors, for example with monoclonal antibodies, aim to thwart pathogen-driven damage and restore an advantage to the immune system. A pioneering technology addressing this challenge is biomimetic nanoparticles-a therapeutic platform featuring nanoscale particles enveloped in natural cell membranes. Borne from the quest for a durable drug delivery system, the original red blood cell-coated nanoparticles showcased a broad capacity to absorb bacterial and environmental toxins from serum. Tailoring the membrane coating to immune cell sources imparts unique characteristics to the nanoparticles suitable for broader application in infectious disease. Their capacity to bind both inflammatory signals and virulence factors assembles the most promising sepsis therapies into a singular, pathogen-agnostic therapeutic. This review explores the ongoing work on immune cell-coated nanoparticle therapeutics for infection and sepsis. SIGNIFICANCE STATEMENT: Invasive bacterial infections and sepsis are a major global health problem made worse by expanding antibiotic resistance, meaning better treatment options are urgently needed. Biomimetic cell-membrane-coated nanoparticles are an innovative therapeutic platform that deploys a multifaceted mechanism to action to neutralize microbial virulence factors, capture endotoxins, and bind excessive host proinflammatory cytokines, seeking to reduce host tissue injury, aid in microbial clearance, and improve patient outcomes.
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Affiliation(s)
- Alexandria Hoffman
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, UC San Diego School of Medicine, La Jolla, California (A.H., V.N.); and Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, California (V.N.)
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, UC San Diego School of Medicine, La Jolla, California (A.H., V.N.); and Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, California (V.N.)
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2
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Liu A, Garrett S, Hong W, Zhang J. Staphylococcus aureus Infections and Human Intestinal Microbiota. Pathogens 2024; 13:276. [PMID: 38668232 PMCID: PMC11053856 DOI: 10.3390/pathogens13040276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/18/2024] [Accepted: 03/23/2024] [Indexed: 04/29/2024] Open
Abstract
Staphylococcus aureus (S. aureus) is a common pathogen that can cause many human diseases, such as skin infection, food poisoning, endocarditis, and sepsis. These diseases can be minor infections or life-threatening, requiring complex medical management resulting in substantial healthcare costs. Meanwhile, as the critically ignored "organ," the intestinal microbiome greatly impacts physiological health, not only in gastrointestinal diseases but also in disorders beyond the gut. However, the correlation between S. aureus infection and intestinal microbial homeostasis is largely unknown. Here, we summarized the recent progress in understanding S. aureus infections and their interactions with the microbiome in the intestine. These summarizations will help us understand the mechanisms behind these infections and crosstalk and the challenges we are facing now, which could contribute to preventing S. aureus infections, effective treatment investigation, and vaccine development.
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Affiliation(s)
- Aotong Liu
- Department of Pharmacology & Regenerative Medicine, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA;
| | - Shari Garrett
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA;
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL 60612, USA
| | - Wanqing Hong
- Faculty of Science, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
- School of Chemistry & Chemical Engineering and Materials Sciences, Shandong Normal University, Jinan 250061, China
| | - Jilei Zhang
- Department of Pharmacology & Regenerative Medicine, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA;
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3
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Mei M, Lu M, Li S, Ren X, Xing B, Hu Y, Wu Y, Chen H, Wang L, Yi L, Ming K, Wei Z. Development of nanobodies specific to clumping factors A of Staphylococcus aureus by yeast surface display. Int J Biol Macromol 2024; 259:129208. [PMID: 38185298 DOI: 10.1016/j.ijbiomac.2024.129208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/25/2023] [Accepted: 01/01/2024] [Indexed: 01/09/2024]
Abstract
The Staphylococcus aureus clumping factor A (ClfA) is a fibrinogen (Fg) binding protein that plays an important role in the clumping of S. aureus in blood plasma. The current anti-infective approaches targeting ClfA are mainly based on monoclonal antibodies but showed less impressive efficacy for clinical applications. Nanobodies offer advantages in enhanced tissue penetration and a propensity to bind small epitopes. However, there is no report on generating specific nanobodies for ClfA. Here, we constructed a synthetic nanobody library based on yeast surface display to isolate nanobodies against the Fg binding domain ClfA221-550. We firstly obtained a primary nanobody directed to ClfA221-550, and then employed error-prone mutagenesis to enhance its binding affinity. Finally, 18 variants were isolated with high affinities (EC50, 1.1 ± 0.1 nM to 4.8 ± 0.3 nM), in which CNb1 presented the highest inhibition efficiency in the adhesion of S. aureus to fibrinogen. Moreover, structural simulation analysis indicated that the epitope for CNb1 partially overlapped with the binding sites for fibrinogen, thus inhibiting ClfA binding to Fg. Overall, these results indicated that the specific nanobodies generated here could prevent the adhesion of S. aureus to fibrinogen, suggesting their potential capacities in the control of S. aureus infections.
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Affiliation(s)
- Meng Mei
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China; Hubei Jiangxia Laboratory, Wuhan, Hubei, China
| | - Mengqing Lu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Shiqi Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Xinyi Ren
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Banbin Xing
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Yang Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Yuqi Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Huan Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Longhao Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Li Yi
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Ke Ming
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China; Hubei Jiangxia Laboratory, Wuhan, Hubei, China
| | - Zigong Wei
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China; Hubei Jiangxia Laboratory, Wuhan, Hubei, China; Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, National & Local Joint Engineering Research Center of High-throughput Drug Screening Technology, School of life sciences, Hubei University, Wuhan, Hubei, PR China.
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4
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Negrón O, Weggeman M, Grimbergen J, Clark EG, Abrahams S, Hur WS, Koopman J, Flick MJ. Fibrinogen γ' promotes host survival during Staphylococcus aureus septicemia in mice. J Thromb Haemost 2023; 21:2277-2290. [PMID: 37001817 PMCID: PMC10528022 DOI: 10.1016/j.jtha.2023.03.019] [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: 02/09/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/31/2023]
Abstract
BACKGROUND Staphylococcus aureus is a common gram-positive bacterium that is the causative agent for several human diseases, including sepsis. A key virulence mechanism is pathogen binding to host fibrinogen through the C-terminal region of the γ-chain. Previous work demonstrated that FggΔ5 mice expressing mutant fibrinogen γΔ5 lacking a S. aureus binding motif had significantly improved survival following S. aureus septicemia. Fibrinogen γ' is a human splice variant that represents about 10% to 15% of the total fibrinogen in plasma and circulates as a fibrinogen γ'-γ heterodimer (phFibγ'-γ). The fibrinogen γ'-chain is also expected to lack S. aureus binding function. OBJECTIVE Determine if human fibrinogen γ'-γ confers host protection during S. aureus septicemia. METHODS Analyses of survival and the host response following S. aureus septicemia challenge in FggΔ5 mice and mice reconstituted with purified phFibγ'-γ or phFibγ-γ. RESULTS Reconstitution of fibrinogen-deficient or wildtype mice with purified phFibγ'-γ prior to infection provided a significant prolongation in host survival relative to mice reconstituted with purified phFibγ-γ, which was superior to that observed with heterozygous FggΔ5 mice. Improved survival could not be accounted for by quantitative differences in fibrinogen-dependent adhesion or clumping, but phFibγ'-γ-containing mixtures generated notably smaller bacterial aggregates. Importantly, administration of phFibγ'-γ after infection also provided a therapeutic benefit by prolonging host survival relative to administration of phFibγ-γ. CONCLUSION These findings provide the proof-of-concept that changing the ratio of naturally occurring fibrinogen variants in blood could offer significant therapeutic potential against bacterial infection and potentially other diseases.
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Affiliation(s)
- Oscar Negrón
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | | | | - Emily G Clark
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sara Abrahams
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Woosuk S Hur
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | | - Matthew J Flick
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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Hsieh RC, Liu R, Burgin DJ, Otto M. Understanding mechanisms of virulence in MRSA: implications for antivirulence treatment strategies. Expert Rev Anti Infect Ther 2023; 21:911-928. [PMID: 37501364 DOI: 10.1080/14787210.2023.2242585] [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: 05/15/2023] [Accepted: 07/26/2023] [Indexed: 07/29/2023]
Abstract
INTRODUCTION Methicillin-resistant Staphylococcus aureus (MRSA) is a widespread pathogen, often causing recurrent and deadly infections in the hospital and community. Many S. aureus virulence factors have been suggested as potential targets for antivirulence therapy to decrease the threat of diminishing antibiotic availability. Antivirulence methods hold promise due to their adjunctive and prophylactic potential and decreased risk for selective pressure. AREAS COVERED This review describes the dominant virulence mechanisms exerted by MRSA and antivirulence therapeutics that are currently undergoing testing in clinical or preclinical stages. We also discuss the advantages and downsides of several investigational antivirulence approaches, including the targeting of bacterial transporters, host-directed therapy, and quorum-sensing inhibitors. For this review, a systematic search of literature on PubMed, Google Scholar, and Web of Science for relevant search terms was performed in April and May 2023. EXPERT OPINION Vaccine and antibody strategies have failed in clinical trials and could benefit from more basic science-informed approaches. Antivirulence-targeting approaches need to be set up better to meet the requirements of drug development, rather than only providing limited results to provide 'proof-of-principle' translational value of pathogenesis research. Nevertheless, there is great potential of such strategies and potential particular promise for novel probiotic approaches.
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Affiliation(s)
- Roger C Hsieh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Dylan J Burgin
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
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6
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Patel H, Rawat S. A genetic regulatory see-saw of biofilm and virulence in MRSA pathogenesis. Front Microbiol 2023; 14:1204428. [PMID: 37434702 PMCID: PMC10332168 DOI: 10.3389/fmicb.2023.1204428] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/30/2023] [Indexed: 07/13/2023] Open
Abstract
Staphylococcus aureus is one of the most common opportunistic human pathogens causing several infectious diseases. Ever since the emergence of the first methicillin-resistant Staphylococcus aureus (MRSA) strain decades back, the organism has been a major cause of hospital-acquired infections (HA-MRSA). The spread of this pathogen across the community led to the emergence of a more virulent subtype of the strain, i.e., Community acquired Methicillin resistant Staphylococcus aureus (CA-MRSA). Hence, WHO has declared Staphylococcus aureus as a high-priority pathogen. MRSA pathogenesis is remarkable because of the ability of this "superbug" to form robust biofilm both in vivo and in vitro by the formation of polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA), wall teichoic acids (WTAs), and capsule (CP), which are major components that impart stability to a biofilm. On the other hand, secretion of a diverse array of virulence factors such as hemolysins, leukotoxins, enterotoxins, and Protein A regulated by agr and sae two-component systems (TCS) aids in combating host immune response. The up- and downregulation of adhesion genes involved in biofilm formation and genes responsible for synthesizing virulence factors during different stages of infection act as a genetic regulatory see-saw in the pathogenesis of MRSA. This review provides insight into the evolution and pathogenesis of MRSA infections with a focus on genetic regulation of biofilm formation and virulence factors secretion.
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Affiliation(s)
| | - Seema Rawat
- Microbiology Laboratory, School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India
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7
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Activation of Human Platelets by Staphylococcus aureus Secreted Protease Staphopain A. Pathogens 2022; 11:pathogens11111237. [DOI: 10.3390/pathogens11111237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
Infection by Staphylococcus aureus is the leading cause of infective endocarditis (IE). Activation of platelets by this pathogen results in their aggregation and thrombus formation which are considered to be important steps in the development and pathogenesis of IE. Here, we show that a secreted cysteine protease, staphopain A, activates human platelets and induces their aggregation. The culture supernatant of a scpA mutant deficient in staphopain A production was reduced in its ability to trigger platelet aggregation. The platelet agonist activity of purified staphopain A was inhibited by staphostatin A, a specific inhibitor, thus implicating its protease activity in the agonism. In whole blood, using concentrations of staphopain A that were otherwise insufficient to induce platelet aggregation, increased binding to collagen and thrombus formation was observed. Using antagonists specific to protease-activated receptors 1 and 4, we demonstrate their role in mediating staphopain A induced platelet activation.
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8
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Wei Y, Liu J, Liu G, Gao S, Wu D, Yang L, Luo R, Zhang F, Wang Y. Hemocompatibility Multi-in-One Hydrogel Coating with ROS-Triggered Inflammation Suppression and Anti-Infection Properties for Blood-Contacting Device. Biomacromolecules 2022; 23:4357-4369. [PMID: 36166656 DOI: 10.1021/acs.biomac.2c00815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In traditional blood-contacting medical devices, infection and thrombosis are easily formed on the surface of the materials. In addition, inflammation is also a clinical complication that cannot be ignored. More importantly, there is a mutually promoting relationship between the inflammatory response and the infection as well as thrombosis. In this work, we propose a self-adaptive anti-inflammatory coating strategy combined with anti-infection and anticoagulant capacity, which was accomplished based on nano-Ag particles and dexamethasone (Dex)-loaded hydrogel coating. The coating loaded with nano-Ag endows it with good bactericidal performance, including Gram-positive and Gram-negative bacteria. As an anti-inflammatory drug, Dex was grafted onto hydrogel coating by a reactive oxygen species (ROS)-cleavable thioketal (TK) bond and released upon the trigger of an inflammatory environment, blocking further inflammatory cascade, providing self-adaptive anti-inflammatory properties, and avoiding side effects of the drug. It was demonstrated that the coating worked as a precise strategy to resist coagulation, infection, and inflammation, provided a new perspective for designing clinical complication-conformable coatings, and had great application prospects on blood-contacting medical devices.
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Affiliation(s)
- Yuan Wei
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
| | - Jingze Liu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
| | - Gongyan Liu
- Collage of Biomass Chemistry and Engineering, Sichuan University, Chengdu 610064, P. R. China
| | - Shuai Gao
- Chengdu Daxan Innovative Medical Tech. Co., Ltd., Chengdu 611135, P. R. China
| | - Dimeng Wu
- Chengdu Daxan Innovative Medical Tech. Co., Ltd., Chengdu 611135, P. R. China
| | - Li Yang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
| | - Rifang Luo
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
| | - Fanjun Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
| | - Yunbing Wang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China
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9
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Pant N, Miranda-Hernandez S, Rush C, Warner J, Eisen DP. Non-Antimicrobial Adjuvant Therapy Using Ticagrelor Reduced Biofilm-Related Staphylococcus aureus Prosthetic Joint Infection. Front Pharmacol 2022; 13:927783. [PMID: 35846990 PMCID: PMC9284533 DOI: 10.3389/fphar.2022.927783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Prosthetic joint infection (PJI), frequently caused by Staphylococcus aureus, leads to a significant arthroplasty failure rate. Biofilm is a crucial virulence factor of S. aureus that is intrinsic to the pathogenesis of PJI. Biofilm-related infections are recalcitrant to antibiotic treatment. Surgical and antibiotic therapy could be combined with non-antibacterial adjuvants to improve overall treatment success. Ticagrelor, a P2Y12 receptor inhibitor antiplatelet drug, is known to have anti-staphylococcal antibacterial and antibiofilm activity. However, the molecular mechanism for ticagrelor’s antibiofilm activity and its efficacy in the treatment of S. aureus PJI are unknown.Methods: To study the in vitro antibacterial and antibiofilm activity of ticagrelor, broth microdilution and crystal violet staining method were used. Ticagrelor’s effect on the expression of S. aureus biofilm genes (icaA, icaD, ebps, fib, eno, and agr) was studied using the relative quantification method. To test ticagrelor’s in vivo efficacy to treat S. aureus PJI, mice were randomized into five groups (n = 8/group): infected femoral implants treated with ticagrelor alone; infected implants treated with cefazolin alone; infected implants treated with ticagrelor and cefazolin; infected implants treated with phosphate buffer solution (PBS)-positive controls, and sterile implants-negative controls. Ticagrelor was administered orally from day 4 to day 7 post-surgery, while cefazolin was injected intravenously on day 7.Results: Ticagrelor, alone and with selected antibiotics, showed in vitro antibacterial and antibiofilm activity against S. aureus. Strain-specific downregulation of biofilm-related genes, fib, icaD, ebps, and eno, was shown. In an animal model of biofilm-related S. aureus PJI, ticagrelor alone and combined with cefazolin significantly reduced bacterial concentrations on the implants compared with the positive control group. Ticagrelor significantly reduced bacterial dissemination to periprosthetic tissue compared with the positive controls.Conclusion: Ticagrelor adjuvant therapy reduced S. aureus PJI in an animal model. However, this study is very preliminary to make a conclusion on the clinical implication of the findings. Based on the current results, more studies are recommended to better understand its implication.
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Affiliation(s)
- Narayan Pant
- College of Medicine and Dentistry, James Cook University, Townsville, QLD, Australia
- Australian Institute of Tropical Health and Medicine, Townsville, QLD, Australia
- *Correspondence: Narayan Pant,
| | | | - Catherine Rush
- Australian Institute of Tropical Health and Medicine, Townsville, QLD, Australia
| | - Jeffrey Warner
- Australian Institute of Tropical Health and Medicine, Townsville, QLD, Australia
| | - Damon P. Eisen
- College of Medicine and Dentistry, James Cook University, Townsville, QLD, Australia
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Chaudhary PK, Kim S, Kim S. An Insight into Recent Advances on Platelet Function in Health and Disease. Int J Mol Sci 2022; 23:ijms23116022. [PMID: 35682700 PMCID: PMC9181192 DOI: 10.3390/ijms23116022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/22/2022] [Accepted: 05/24/2022] [Indexed: 12/04/2022] Open
Abstract
Platelets play a variety of roles in vascular biology and are best recognized as primary hemostasis and thrombosis mediators. Platelets have a large number of receptors and secretory molecules that are required for platelet functionality. Upon activation, platelets release multiple substances that have the ability to influence both physiological and pathophysiological processes including inflammation, tissue regeneration and repair, cancer progression, and spreading. The involvement of platelets in the progression and seriousness of a variety of disorders other than thrombosis is still being discovered, especially in the areas of inflammation and the immunological response. This review represents an integrated summary of recent advances on the function of platelets in pathophysiology that connects hemostasis, inflammation, and immunological response in health and disease and suggests that antiplatelet treatment might be used for more than only thrombosis.
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11
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Gonzalez DA, Kumar R, Asif S, Bali A, Dang AK. Sepsis and Thrombocytopenia: A Nowadays Problem. Cureus 2022; 14:e25421. [PMID: 35774677 PMCID: PMC9236694 DOI: 10.7759/cureus.25421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2022] [Indexed: 12/11/2022] Open
Abstract
Sepsis is a life-threatening organ failure produced by a dysregulated host response to infection that involves 15.6% of hospital mortality. The most common signs and symptoms of sepsis are hypotension, tachypnea, fever, and leukocytosis, whether suspected or confirmed. Including a major one, thrombocytopenia is a sign that is an independent predictor of poor outcomes in patients with sepsis, increasing their mortality rate and their length of stay in the intensive care unit (ICU). So far, the ongoing treatment for this problem is securing the airway, treating hypoxemia, and providing vascular access for hydration, antibiotic delivery, and vasopressors, if needed. This article has reviewed the different possible mechanisms found for sepsis-associated thrombocytopenia, going from the most acknowledged one as decreased platelet production to the potential aftermath of sepsis itself as disseminated intravascular coagulation (DIC). This article has also discussed the future treatment for patients suffering from thrombocytopenia and sepsis, going from phase I and II trials as GI antagonists to the well-known drug aspirin as a possible treatment for this problem.
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12
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Garcia C, Compagnon B, Poëtte M, Gratacap MP, Lapébie FX, Voisin S, Minville V, Payrastre B, Vardon-Bounes F, Ribes A. Platelet Versus Megakaryocyte: Who Is the Real Bandleader of Thromboinflammation in Sepsis? Cells 2022; 11:1507. [PMID: 35563812 PMCID: PMC9104300 DOI: 10.3390/cells11091507] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/24/2022] Open
Abstract
Platelets are mainly known for their key role in hemostasis and thrombosis. However, studies over the last two decades have shown their strong implication in mechanisms associated with inflammation, thrombosis, and the immune system in various neoplastic, inflammatory, autoimmune, and infectious diseases. During sepsis, platelets amplify the recruitment and activation of innate immune cells at the site of infection and contribute to the elimination of pathogens. In certain conditions, these mechanisms can lead to thromboinflammation resulting in severe organ dysfunction. Here, we discuss the interactions of platelets with leukocytes, neutrophil extracellular traps (NETs), and endothelial cells during sepsis. The intrinsic properties of platelets that generate an inflammatory signal through the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome are discussed. As an example of immunothrombosis, the implication of platelets in vaccine-induced immune thrombotic thrombocytopenia is documented. Finally, we discuss the role of megakaryocytes (MKs) in thromboinflammation and their adaptive responses.
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Affiliation(s)
- Cédric Garcia
- Laboratoire d’Hématologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France; (C.G.); (S.V.); (B.P.)
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm UMR1297 and Université Toulouse 3, 31024 Toulouse, France; (B.C.); (M.P.); (M.-P.G.); (F.V.-B.)
| | - Baptiste Compagnon
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm UMR1297 and Université Toulouse 3, 31024 Toulouse, France; (B.C.); (M.P.); (M.-P.G.); (F.V.-B.)
- Pôle Anesthésie-Réanimation, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France;
| | - Michaël Poëtte
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm UMR1297 and Université Toulouse 3, 31024 Toulouse, France; (B.C.); (M.P.); (M.-P.G.); (F.V.-B.)
- Pôle Anesthésie-Réanimation, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France;
| | - Marie-Pierre Gratacap
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm UMR1297 and Université Toulouse 3, 31024 Toulouse, France; (B.C.); (M.P.); (M.-P.G.); (F.V.-B.)
| | - François-Xavier Lapébie
- Service de Médecine Vasculaire, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France;
| | - Sophie Voisin
- Laboratoire d’Hématologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France; (C.G.); (S.V.); (B.P.)
| | - Vincent Minville
- Pôle Anesthésie-Réanimation, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France;
| | - Bernard Payrastre
- Laboratoire d’Hématologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France; (C.G.); (S.V.); (B.P.)
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm UMR1297 and Université Toulouse 3, 31024 Toulouse, France; (B.C.); (M.P.); (M.-P.G.); (F.V.-B.)
| | - Fanny Vardon-Bounes
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm UMR1297 and Université Toulouse 3, 31024 Toulouse, France; (B.C.); (M.P.); (M.-P.G.); (F.V.-B.)
- Pôle Anesthésie-Réanimation, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France;
| | - Agnès Ribes
- Laboratoire d’Hématologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France; (C.G.); (S.V.); (B.P.)
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm UMR1297 and Université Toulouse 3, 31024 Toulouse, France; (B.C.); (M.P.); (M.-P.G.); (F.V.-B.)
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13
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Burgin DJ, Liu R, Hsieh RC, Heinzinger LR, Otto M. Investigational agents for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia: progress in clinical trials. Expert Opin Investig Drugs 2022; 31:263-279. [PMID: 35129409 PMCID: PMC10988647 DOI: 10.1080/13543784.2022.2040015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/06/2022] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Bacteremia caused by Staphylococcus aureus is common. Cases caused by methicillin-resistant S. aureus (MRSA) are particularly formidable and often lethal. The mortality associated with MRSA bacteremia has not significantly decreased over the past couple of decades and concerns regarding efficacy and toxicity of standard therapy highlight the need for novel agents and new therapeutic approaches. AREAS COVERED This paper explores clinical trials investigating novel therapeutic approaches to S. aureus bacteremia. There is a special focus on MRSA bacteremia. Monotherapy and combination therapies and novel antimicrobials and adjunctive therapies that are only recently being established for therapeutic use are discussed. EXPERT OPINION The unfavorable safety profile of combination antimicrobial therapy in clinical trials has outweighed its benefits. Therefore, future investigation should focus on optimizing duration and de-escalation protocols. Antibody and bacteriophage lysin-based candidates have mostly been limited to safety trials, but progress with these agents is demonstrated through a lysin-based agent receiving a phase III trial. Antibiotics indicated for use in treating MRSA skin infections see continued investigation as treatments for MRSA bacteremia despite the difficulty of completing trials in this patient population. Promising agents include dalbavancin, ceftobiprole, ceftaroline, and exebacase.
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Affiliation(s)
- Dylan J. Burgin
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Roger C. Hsieh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lauren R. Heinzinger
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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14
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Tatara AM, Gandhi RG, Mooney DJ, Nelson SB. Antiplatelet therapy for Staphylococcus aureus bacteremia: Will it stick? PLoS Pathog 2022; 18:e1010240. [PMID: 35143595 PMCID: PMC8830658 DOI: 10.1371/journal.ppat.1010240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Staphylococcus aureus bacteremia (SAB) remains a clinically challenging infection despite extensive investigation. Repurposing medications approved for other indications is appealing as clinical safety profiles have already been established. Ticagrelor, a reversible adenosine diphosphate receptor antagonist that prevents platelet aggregation, is indicated for patients suffering from acute coronary syndrome (ACS). However, some clinical data suggest that patients treated with ticagrelor are less likely to have poor outcomes due to S. aureus infection. There are several potential mechanisms by which ticagrelor may affect S. aureus virulence. These include direct antibacterial activity, up-regulation of the innate immune system through boosting platelet-mediated S. aureus killing, and prevention of S. aureus adhesion to host tissues. In this Pearl, we review the clinical data surrounding ticagrelor and infection as well as explore the evidence surrounding these proposed mechanisms of action. While more evidence is needed before antiplatelet medications formally become part of the arsenal against S. aureus infection, these potential mechanisms represent exciting pathways to target in the host/pathogen interface.
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Affiliation(s)
- Alexander M. Tatara
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Ronak G. Gandhi
- Department of Pharmacy, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - David J. Mooney
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Sandra B. Nelson
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- * E-mail:
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15
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Schwarz C, Töre Y, Hoesker V, Ameling S, Grün K, Völker U, Schulze PC, Franz M, Faber C, Schaumburg F, Niemann S, Hoerr V. Host-pathogen interactions of clinical S. aureus isolates to induce infective endocarditis. Virulence 2021; 12:2073-2087. [PMID: 34490828 PMCID: PMC8425731 DOI: 10.1080/21505594.2021.1960107] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
To evaluate potential pathomechanisms in the induction of infective endocarditis (IE), 34 Staphylococcus aureus (S. aureus) isolates, collected from patients with S. aureus endocarditis and from healthy individuals were investigated both in vitro and in vivo. S. aureus isolates were tested in vitro for their cytotoxicity, invasion and the association with platelets. Virulence factor expression profiles and cellular response were additionally investigated and tested for correlation with the ability of S. aureus to induce vegetations on the aortic valves in vivo. In an animal model of IE valvular conspicuity was assessed by in vivo magnetic resonance imaging at 9.4 T, histology and enrichment gene expression analysis. All S. aureus isolates tested in vivo caused a reliable infection and inflammation of the aortic valves, but could not be differentiated and categorized according to the measured in vitro virulence profiles and cytotoxicity. Results from in vitro assays did not correlate with the severity of IE. However, the isolates differed substantially in the activation and inhibition of pathways connected to the extracellular matrix and inflammatory response. Thus, comprehensive approaches of host-pathogen interactions and corresponding immune pathways are needed for the evaluation of the pathogenic capacity of bacteria. An improved understanding of the interaction between virulence factors and immune response in S. aureus infective endocarditis would offer novel possibilities for the development of therapeutic strategies and specific diagnostic imaging markers.
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Affiliation(s)
- Christian Schwarz
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Muenster, Muenster, Germany
| | - Yasemin Töre
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Muenster, Muenster, Germany
| | - Vanessa Hoesker
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Muenster, Muenster, Germany
| | - Sabine Ameling
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany
| | - Katja Grün
- Department of Internal Medicine I, Jena University Hospital, Jena, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany
| | | | - Marcus Franz
- Department of Internal Medicine I, Jena University Hospital, Jena, Germany
| | - Cornelius Faber
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Muenster, Muenster, Germany
| | - Frieder Schaumburg
- Institute of Medical Microbiology, University Hospital Muenster, Muenster, Germany
| | - Silke Niemann
- Institute of Medical Microbiology, University Hospital Muenster, Muenster, Germany
| | - Verena Hoerr
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Muenster, Muenster, Germany.,Institute of Medical Microbiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany.,Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
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16
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Lerche CJ, Schwartz F, Theut M, Fosbøl EL, Iversen K, Bundgaard H, Høiby N, Moser C. Anti-biofilm Approach in Infective Endocarditis Exposes New Treatment Strategies for Improved Outcome. Front Cell Dev Biol 2021; 9:643335. [PMID: 34222225 PMCID: PMC8249808 DOI: 10.3389/fcell.2021.643335] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 05/04/2021] [Indexed: 12/13/2022] Open
Abstract
Infective endocarditis (IE) is a life-threatening infective disease with increasing incidence worldwide. From early on, in the antibiotic era, it was recognized that high-dose and long-term antibiotic therapy was correlated to improved outcome. In addition, for several of the common microbial IE etiologies, the use of combination antibiotic therapy further improves outcome. IE vegetations on affected heart valves from patients and experimental animal models resemble biofilm infections. Besides the recalcitrant nature of IE, the microorganisms often present in an aggregated form, and gradients of bacterial activity in the vegetations can be observed. Even after appropriate antibiotic therapy, such microbial formations can often be identified in surgically removed, infected heart valves. Therefore, persistent or recurrent cases of IE, after apparent initial infection control, can be related to biofilm formation in the heart valve vegetations. On this background, the present review will describe potentially novel non-antibiotic, antimicrobial approaches in IE, with special focus on anti-thrombotic strategies and hyperbaric oxygen therapy targeting the biofilm formation of the infected heart valves caused by Staphylococcus aureus. The format is translational from preclinical models to actual clinical treatment strategies.
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Affiliation(s)
- Christian Johann Lerche
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Franziska Schwartz
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Marie Theut
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Emil Loldrup Fosbøl
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kasper Iversen
- Department of Cardiology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark.,Department of Emergency Medicine, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - Henning Bundgaard
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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17
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Kim CJ, Song KH, Choe PG, Park WB, Kim ES, Park KU, Kim NJ, Park KH, Kwak YG, Cheon S, Jang HC, Kim YK, Lee SH, Kiem SM, Lee S, Kim HB, Oh MD. The microbiological characteristics of Staphylococcus aureus isolated from patients with native valve infective endocarditis. Virulence 2020; 10:948-956. [PMID: 31718473 PMCID: PMC8647854 DOI: 10.1080/21505594.2019.1685631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The microbiological characteristics of Staphylococcus aureus causing infective endocarditis (IE) have not been investigated thoroughly. We compared the characteristics of S. aureus isolates from patients with and without IE. Cases of S. aureus bacteremia (SAB) were collected from 10 hospitals over 7 years. Cases of native valve IE were matched with non-IE controls according to the following criteria: central-line-associated infection, community-acquired infection, methicillin susceptibility, and if possible, the primary site of infection. Genes coding virulence factors were analyzed using multiplex polymerase chain reactions. Fibrinogen and fibronectin-binding properties were assessed using in vitro binding assays. The fibronectin-binding protein A gene (fnbpA) was sequenced. Of 2,365 cases of SAB, 92 had IE. After matching, 37 pairs of S. aureus isolates from the IE cases and non-IE controls were compared; fnbpA was detected in 91.9% of the IE isolates and 100% of the non-IE isolates (p = 0.24). While the fibrinogen binding ratio was similar (1.07 ± 0.33 vs. 1.08 ± 0.26, p = 0.89), the fibronectin-binding ratio was significantly higher in the IE-group (1.31 ± 0.42 vs. 1.06 ± 0.31, p = 0.01). The proportions of major single-nucleotide polymorphisms in fnbpA were as follows: E652D (2.9% vs. 2.7%), H782Q (65.6% vs. 60.6%), and K786N (65.6% vs. 72.7%). The fibronectin-binding ratio was positively correlated with the number of SNPs present in IE cases (p < 0.001) but not in the non-IE controls (p = 0.124). Fibronectin-binding might play a key role in SAB IE. However, the degree of binding may be mediated by genetic variability between isolates.
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Affiliation(s)
- Chung-Jong Kim
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Seoul, Republic of Korea
| | - Kyoung-Ho Song
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.,Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Pyoeng Gyun Choe
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Wan Beom Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Eu Suk Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.,Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyoung Un Park
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Nam Joong Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Kyung-Hwa Park
- Department of Infectious Diseases, Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Yee Gyung Kwak
- Department of Internal Medicine, Inje University Ilsan Paik Hospital, Goyang, Republic of Korea
| | - Shinhye Cheon
- Division of Infectious Diseases, Department of Internal Medicine, Chungnam National University School of Medicine, Daejon, Republic of Korea
| | - Hee-Chang Jang
- Department of Internal Medicine, Chonnam National University Hwasun Hospital, Hwasun, Republic of Korea
| | - Young Keun Kim
- Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - Sun Hee Lee
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - Sung-Min Kiem
- Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, South Korea
| | - Shinwon Lee
- Department of Internal Medicine, Daegu Fatima Hospital, Daegu, South Korea
| | - Hong Bin Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.,Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Myoung-Don Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
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18
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Maddur AA, Kroh HK, Aschenbrenner ME, Gibson BHY, Panizzi P, Sheehan JH, Meiler J, Bock PE, Verhamme IM. Specificity and affinity of the N-terminal residues in staphylocoagulase in binding to prothrombin. J Biol Chem 2020; 295:5614-5625. [PMID: 32156702 PMCID: PMC7186164 DOI: 10.1074/jbc.ra120.012588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/09/2020] [Indexed: 11/06/2022] Open
Abstract
In Staphylococcus aureus-caused endocarditis, the pathogen secretes staphylocoagulase (SC), thereby activating human prothrombin (ProT) and evading immune clearance. A previous structural comparison of the SC(1-325) fragment bound to thrombin and its inactive precursor prethrombin 2 has indicated that SC activates ProT by inserting its N-terminal dipeptide Ile1-Val2 into the ProT Ile16 pocket, forming a salt bridge with ProT's Asp194, thereby stabilizing the active conformation. We hypothesized that these N-terminal SC residues modulate ProT binding and activation. Here, we generated labeled SC(1-246) as a probe for competitively defining the affinities of N-terminal SC(1-246) variants preselected by modeling. Using ProT(R155Q,R271Q,R284Q) (ProTQQQ), a variant refractory to prothrombinase- or thrombin-mediated cleavage, we observed variant affinities between ∼1 and 650 nm and activation potencies ranging from 1.8-fold that of WT SC(1-246) to complete loss of function. Substrate binding to ProTQQQ caused allosteric tightening of the affinity of most SC(1-246) variants, consistent with zymogen activation through occupation of the specificity pocket. Conservative changes at positions 1 and 2 were well-tolerated, with Val1-Val2, Ile1-Ala2, and Leu1-Val2 variants exhibiting ProTQQQ affinity and activation potency comparable with WT SC(1-246). Weaker binding variants typically had reduced activation rates, although at near-saturating ProTQQQ levels, several variants exhibited limiting rates similar to or higher than that of WT SC(1-246). The Ile16 pocket in ProTQQQ appears to favor nonpolar, nonaromatic residues at SC positions 1 and 2. Our results suggest that SC variants other than WT Ile1-Val2-Thr3 might emerge with similar ProT-activating efficiency.
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Affiliation(s)
- Ashoka A Maddur
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561.
| | - Heather K Kroh
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Mary E Aschenbrenner
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Breanne H Y Gibson
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Peter Panizzi
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama 36849
| | - Jonathan H Sheehan
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232; Institute for Drug Discovery, Departments of Chemistry and Computer Science, Leipzig University Medical School, SAC 04103 Leipzig, Germany
| | - Paul E Bock
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561
| | - Ingrid M Verhamme
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2561.
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19
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Assinger A, Schrottmaier WC, Salzmann M, Rayes J. Platelets in Sepsis: An Update on Experimental Models and Clinical Data. Front Immunol 2019; 10:1687. [PMID: 31379873 PMCID: PMC6650595 DOI: 10.3389/fimmu.2019.01687] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/04/2019] [Indexed: 12/22/2022] Open
Abstract
Beyond their important role in hemostasis, platelets play a crucial role in inflammatory diseases. This becomes apparent during sepsis, where platelet count and activation correlate with disease outcome and survival. Sepsis is caused by a dysregulated host response to infection, leading to organ dysfunction, permanent disabilities, or death. During sepsis, tissue injury results from the concomitant uncontrolled activation of the complement, coagulation, and inflammatory systems as well as platelet dysfunction. The balance between the systemic inflammatory response syndrome (SIRS) and the compensatory anti-inflammatory response (CARS) regulates sepsis outcome. Persistent thrombocytopenia is considered as an independent risk factor of mortality in sepsis, although it is still unclear whether the drop in platelet count is the cause or the consequence of sepsis severity. The role of platelets in sepsis development and progression was addressed in different experimental in vivo models, particularly in mice, that represent various aspects of human sepsis. The immunomodulatory function of platelets depends on the experimental model, time, and type of infection. Understanding the molecular mechanism of platelet regulation in inflammation could bring us one step closer to understand this important aspect of primary hemostasis which drives thrombotic as well as bleeding complications in patients with sterile and infectious inflammation. In this review, we summarize the current understanding of the contribution of platelets to sepsis severity and outcome. We highlight the differences between platelet receptors in mice and humans and discuss the potential and limitations of animal models to study platelet-related functions in sepsis.
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Affiliation(s)
- Alice Assinger
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | - Manuel Salzmann
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Julie Rayes
- Institute of Cardiovascular Science, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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20
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Raafat D, Otto M, Reppschläger K, Iqbal J, Holtfreter S. Fighting Staphylococcus aureus Biofilms with Monoclonal Antibodies. Trends Microbiol 2019; 27:303-322. [PMID: 30665698 DOI: 10.1016/j.tim.2018.12.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/10/2018] [Accepted: 12/18/2018] [Indexed: 02/07/2023]
Abstract
Staphylococcus aureus (S. aureus) is a notorious pathogen and one of the most frequent causes of biofilm-related infections. The treatment of S. aureus biofilms is hampered by the ability of the biofilm structure to shield bacteria from antibiotics as well as the host's immune system. Therefore, new preventive and/or therapeutic interventions, including the use of antibody-based approaches, are urgently required. In this review, we describe the mechanisms by which anti-S. aureus antibodies can help in combating biofilms, including an up-to-date overview of monoclonal antibodies currently in clinical trials. Moreover, we highlight ongoing efforts in passive vaccination against S. aureus biofilm infections, with special emphasis on promising targets, and finally indicate the direction into which future research could be heading.
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Affiliation(s)
- Dina Raafat
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Egypt; Current affiliation: Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD, USA
| | - Kevin Reppschläger
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Jawad Iqbal
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Silva Holtfreter
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany.
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21
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Wang FD, Wu PF, Chen SJ. Distribution of virulence genes in bacteremic methicillin-resistant Staphylococcus aureus isolates from various sources. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2019; 52:426-432. [PMID: 30686615 DOI: 10.1016/j.jmii.2019.01.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/04/2019] [Accepted: 01/06/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND/PURPOSE Methicillin-resistant Staphylococcus aureus (MRSA) can encode proteins which directly bind bacteria to many tissues and medical devices or catheters to trigger pathogenesis. However, the relationship between genetic backgrounds and virulent factors in MRSA isolates remained incompletely understood yet. METHODS MRSA isolates were collected from blood cultures of patients with infective endocarditis, bone/joint infection, skin/soft tissue infection, or catheter-related bacteremia in hemodialysis at a tertiary medical center between 2005 and 2011. MRSA isolates were characterized by the methods of spa, multilocus sequence, and staphylococcal cassette chromosome mec (SCCmec) typing. Identification of virulence gene expression was measured by Power SYBR Green PCR Master Mix. RESULTS Overall collected were 136 MRSA bacteremic isolates, including those from the cases of infective endocarditis (n = 23), bone/joint infection (n = 49), skin/soft tissue infection (n = 20), or catheter-related bacteremia in patients with acute kidney injury or end-stage renal stage receiving hemodialysis (n = 54). CC8-ST239-MRSA-SCCmec type III-spa type t037 was the most prevalent type observed in all of 136 MRSA bacteremic isolates. The prevalent genes in the group of infective endocarditis were clfA, clfB, fnbA, ebpS, eap, emp, sae, and eno; bone/joint infections clfA, emp, sae, and eno; skin/soft tissue infection eno; hemodialysis catheter-related bacteremia clfA and sae. The distribution of each gene was not statically different among four groups. CONCLUSIONS A major MRSA lineage, CC8-ST239-MRSA-SCCmec type III-spa type t037, is noted among bacteremic MRSA isolates. No disease-specific virulent genes can be identified.
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Affiliation(s)
- Fu-Der Wang
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei 112, Taiwan; School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
| | - Ping-Feng Wu
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei 112, Taiwan; School of Medicine, National Yang-Ming University, Taipei 112, Taiwan
| | - Su-Jung Chen
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei 112, Taiwan; School of Medicine, National Yang-Ming University, Taipei 112, Taiwan
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22
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Levin J. The Evolution of Mammalian Platelets. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00001-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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23
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The Role of Platelets in Antimicrobial Host Defense. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00029-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Krogh AKH, Haaber J, Bochsen L, Ingmer H, Kristensen AT. Aggregating resistant Staphylococcus aureus induces hypocoagulability, hyperfibrinolysis, phagocytosis, and neutrophil, monocyte, and lymphocyte binding in canine whole blood. Vet Clin Pathol 2018; 47:560-574. [PMID: 30586190 DOI: 10.1111/vcp.12679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 06/07/2018] [Accepted: 06/24/2018] [Indexed: 11/28/2022]
Abstract
BACKGROUND Staphylococcus aureus is an opportunistic pathogen with the ability to form mobile planktonic aggregates during growth, in vitro. The in vivo pathophysiologic effects of S aureus aggregates on host responses are unknown. Knowledge of these could aid in combating infections. OBJECTIVE This study aimed to investigate the effect of increasing concentrations of two different aggregating S aureus strains on the hemostatic and inflammatory host responses in canine whole blood. The hypothesis was that aggregating bacteria would induce pronounced hemostatic and inflammatory responses. METHODS Citrate-stabilized whole blood from 10 healthy dogs was incubated with two strains of aggregating S aureus at three different concentrations. Each sample was analyzed using tissue factor-thromboelastography (TF-TEG) and the formed clot was investigated with electron microscopy. The plasma activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, and D-dimer tests were measured. Bacteria-leukocyte binding was evaluated with flow cytometry, and neutrophil phagocytosis was assessed using light and transmission electron microscopy. RESULTS The highest concentration of bacteria resulted in a significantly shortened TF-TEG initiation time, decreased alpha, maximum amplitude, global strength, and increased lysis. In addition, significantly shortened PT, decreased fibrinogen, and increased D-dimers were demonstrated at the highest concentration of bacteria. Lower concentrations of bacteria showed no differences in TF-TEG when compared with controls. The findings were similar for both S aureus strains. Increased concentration-dependent binding of bacteria and leukocytes and neutrophil bacterial phagocytosis was observed. CONCLUSIONS Two strains of S aureus induced alterations of clot formation in concentrations where bacterial aggregates were formed. A concentration-dependent cellular inflammatory response was observed.
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Affiliation(s)
- Anne K H Krogh
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jakob Haaber
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Louise Bochsen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Annemarie T Kristensen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
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Gurtman A, Begier E, Mohamed N, Baber J, Sabharwal C, Haupt RM, Edwards H, Cooper D, Jansen KU, Anderson AS. The development of a staphylococcus aureus four antigen vaccine for use prior to elective orthopedic surgery. Hum Vaccin Immunother 2018; 15:358-370. [PMID: 30215582 DOI: 10.1080/21645515.2018.1523093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Staphylococcus aureus (S. aureus) is a challenging bacterial pathogen which can cause a range of diseases, from mild skin infections, to more serious and invasive disease including deep or organ space surgical site infections, life-threatening bacteremia, and sepsis. S. aureus rapidly develops resistance to antibiotic treatments. Despite current infection control measures, the burden of disease remains high. The most advanced vaccine in clinical development is a 4 antigen S. aureus vaccine (SA4Ag) candidate that is being evaluated in a phase 2b/3 efficacy study in patients undergoing elective spinal fusion surgery (STaphylococcus aureus suRgical Inpatient Vaccine Efficacy [STRIVE]). SA4Ag has been shown in early phase clinical trials to be generally safe and well tolerated, and to induce high levels of bactericidal antibodies in healthy adults. In this review we discuss the design of SA4Ag, as well as the proposed clinical development plan supporting licensure of SA4Ag for the prevention of invasive disease caused by S. aureus in elective orthopedic surgical populations. We also explore the rationale for the generalizability of the results of the STRIVE efficacy study (patients undergoing elective open posterior multilevel instrumented spinal fusion surgery) to a broad elective orthopedic surgery population due to the common pathophysiology of invasive S. aureus disease and commonalties of patient and procedural risk factors for developing postoperative S. aureus surgical site infections.
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Affiliation(s)
- A Gurtman
- a Pfizer Vaccine Research and Development , Pfizer, Inc ., Pearl River , NY , USA
| | - E Begier
- a Pfizer Vaccine Research and Development , Pfizer, Inc ., Pearl River , NY , USA
| | - N Mohamed
- a Pfizer Vaccine Research and Development , Pfizer, Inc ., Pearl River , NY , USA
| | - J Baber
- b Pfizer Vaccine Research and Development , Sydney , NSW , Australia
| | - C Sabharwal
- a Pfizer Vaccine Research and Development , Pfizer, Inc ., Pearl River , NY , USA
| | - R M Haupt
- c Medical Development, Scientific and Clinical Affairs , Pfizer, Inc ., Collegeville , PA , USA
| | - H Edwards
- d World Wide Regulatory Affairs , Pfizer Inc ., Walton Oaks , UK
| | - D Cooper
- a Pfizer Vaccine Research and Development , Pfizer, Inc ., Pearl River , NY , USA
| | - K U Jansen
- a Pfizer Vaccine Research and Development , Pfizer, Inc ., Pearl River , NY , USA
| | - A S Anderson
- a Pfizer Vaccine Research and Development , Pfizer, Inc ., Pearl River , NY , USA
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Deppermann C, Kubes P. Start a fire, kill the bug: The role of platelets in inflammation and infection. Innate Immun 2018; 24:335-348. [PMID: 30049243 PMCID: PMC6830908 DOI: 10.1177/1753425918789255] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/16/2018] [Accepted: 06/26/2018] [Indexed: 11/19/2022] Open
Abstract
Platelets are the main players in thrombosis and hemostasis; however they also play important roles during inflammation and infection. Through their surface receptors, platelets can directly interact with pathogens and immune cells. Platelets form complexes with neutrophils to modulate their capacities to produce reactive oxygen species or form neutrophil extracellular traps. Furthermore, they release microbicidal factors and cytokines that kill pathogens and influence the immune response, respectively. Platelets also maintain the vascular integrity during inflammation by a mechanism that is different from classical platelet activation. In this review we summarize the current knowledge about how platelets interact with the innate immune system during inflammation and infection and highlight recent advances in the field.
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Affiliation(s)
- Carsten Deppermann
- Calvin, Phoebe and Joan Snyder Institute for Chronic
Diseases, University of Calgary, Calgary, AB, Canada
| | - Paul Kubes
- Calvin, Phoebe and Joan Snyder Institute for Chronic
Diseases, University of Calgary, Calgary, AB, Canada
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27
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Abstract
Nosocomial or hospital-acquired infections are associated with prolonged hospitalizations and increased healthcare costs. Infections associated with surgical implants are becoming more difficult and more costly to manage, as they require repeated surgical procedures and a longer period of time to treat patients. Continued advances in the use of medical devices, an increase in the number of immunocompromised patients, and a steady rise in the prevalence of antibiotic-resistant organisms has renewed interest in the development of novel therapies that can be used to prevent and treat nosocomial infections. This review provides an overview of bacterial adhesins and focuses on novel immunological therapies developed to treat staphylococcal infections.
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Affiliation(s)
- J M Patti
- Inhibitex, Inc., Alpharetta, Georgia, USA.
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28
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Visai L, Arciola CR, Pietrocola G, Rindi S, Olivero P, Speziale P. Staphylococcus Biofilm Components as Targets for Vaccines and Drugs. Int J Artif Organs 2018; 30:813-9. [DOI: 10.1177/039139880703000911] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Staphylococci have become the most common cause of nosocomial infections, especially in patients with predisposing factors such as indwelling or implanted foreign polymer bodies. The pathogenesis of foreign-body associated infections with S. aureus and S. epidermidis is mainly related to the ability of these bacteria to form thick, adherent multilayered biofilms. In a biofilm, staphylococci are protected against antibiotic treatment and attack from the immune system, thus making eradication of the infections problematic. This necessitates the discovery of novel prophylactic and therapeutic strategies to treat these infections. In this review, we provide an overview of staphylococcal biofilm components and discuss new possible approaches to controlling these persistent biofilm-dwelling bacteria.
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Affiliation(s)
- L. Visai
- University of Pavia, Department of Biochemistry, Pavia - Italy
| | - C. R. Arciola
- Research Unit on Implant Infections, Rizzoli Orthopedic Institute, Bologna - Italy
- Department of Experimental Pathology, University of Bologna, Bologna - Italy
| | - G. Pietrocola
- University of Pavia, Department of Biochemistry, Pavia - Italy
| | - S. Rindi
- University of Pavia, Department of Biochemistry, Pavia - Italy
| | - P. Olivero
- University of Pavia, Department of Biochemistry, Pavia - Italy
| | - P. Speziale
- University of Pavia, Department of Biochemistry, Pavia - Italy
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29
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Pressman GS, Rodriguez-Ziccardi M, Gartman CH, Obasare E, Melendres E, Arguello V, Bhalla V. Mitral Annular Calcification as a Possible Nidus for Endocarditis: A Descriptive Series with Bacteriological Differences Noted. J Am Soc Echocardiogr 2017; 30:572-578. [DOI: 10.1016/j.echo.2017.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Indexed: 12/12/2022]
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Abstract
The primary function of platelets is to patrol the vasculature and seal vessel breaches to limit blood loss. However, it is becoming increasingly clear that they also contribute to pathophysiological conditions like thrombosis, atherosclerosis, stroke and infection. Severe sepsis is a devastating disease that claims hundreds of thousands of lives every year in North America and is a major burden to the public health system. Platelet surface receptors like GPIb, αIIbβ3, TLR2 and TLR4 are involved in direct platelet-bacteria interactions. Plasma proteins like fibrinogen and vWF enable indirect interactions. Furthermore, platelet granules contain a plethora of proteins that modulate the immune response as well as microbicidal agents which can directly lyse bacteria. Bacterial toxins are potent platelet activators and can cause intravascular platelet aggregation. Platelets contribute to the antibacterial response of the host involving Kupffer cells, neutrophils and the complement system. In this review we summarize the current knowledge about platelet-bacteria interactions and highlight recent advances in the field.
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Affiliation(s)
- Carsten Deppermann
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Paul Kubes
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.
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31
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Abstract
UNLABELLED Treatment of Staphylococcus aureus infections has become increasingly difficult because of the emergence of multidrug-resistant isolates. Development of a vaccine to prevent staphylococcal infections remains a priority. To determine whether clumping factor A (ClfA) is a good target protein for inclusion in a multivalent vaccine, we evaluated its efficacy in a variety of relevant staphylococcal infection models, challenging with different S. aureus strains. ClfA adsorbed to Alhydrogel and mixed with Sigma Adjuvant System was more immunogenic and stimulated a more robust Th17 response than ClfA administered with alum alone. ClfA immunization induced the production of functional antibodies in rabbits and mice that blocked S. aureus binding to fibrinogen and were opsonic for S. aureus strains that produced little or no capsular polysaccharide. Mice immunized with ClfA showed a modest reduction in the bacterial burden recovered from subcutaneous abscesses provoked by S. aureus USA300 strain LAC. In addition, the ClfA vaccine reduced lethality in a sepsis model following challenge with strain Newman, but not ST80. Vaccination with ClfA did not protect against surgical wound infection, renal abscess formation, or bacteremia. Passive immunization with antibodies to ClfA did not protect against staphylococcal bacteremia in mice or catheter-induced endocarditis in rats. Some enhancement of bacteremia was observed by ClfA immunization or passive administration of ClfA antibodies when mice were challenged by the intraperitoneal route. Although rodent models of staphylococcal infection have their limitations, our data do not support the inclusion of ClfA in an S. aureus multivalent vaccine. IMPORTANCE Antibiotics are often ineffective in eradicating Staphylococcus aureus infections, and thus, a preventative vaccine is sorely needed. Two single-component vaccines and two immunoglobulin preparations failed to meet their designated endpoints in phase III clinical trials. Importantly, recipients of an S. aureus surface protein (iron surface determinant B) vaccine who developed a staphylococcal infection experienced a higher rate of multiorgan failure and mortality than placebo controls, raising safety concerns. Multicomponent S. aureus vaccines have now been generated, and several include surface protein clumping factor A (ClfA). We immunized mice with ClfA and generated a robust T cell response and serum antibodies that were functional in vitro. Nonetheless, ClfA was not protective in a number of relevant animal models of S. aureus infection, and high levels of ClfA antibodies enhanced bacteremia when mice were challenged with community-acquired methicillin-resistant S. aureus strains. Evidence supporting ClfA as a vaccine component is lacking.
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Garciarena CD, McHale TM, Watkin RL, Kerrigan SW. Coordinated Molecular Cross-Talk between Staphylococcus aureus, Endothelial Cells and Platelets in Bloodstream Infection. Pathogens 2015; 4:869-82. [PMID: 26690226 PMCID: PMC4693168 DOI: 10.3390/pathogens4040869] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/02/2015] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen often carried asymptomatically on the human body. Upon entry to the otherwise sterile environment of the cardiovascular system, S. aureus can lead to serious complications resulting in organ failure and death. The success of S. aureus as a pathogen in the bloodstream is due to its ability to express a wide array of cell wall proteins on its surface that recognise host receptors, extracellular matrix proteins and plasma proteins. Endothelial cells and platelets are important cells in the cardiovascular system and are a major target of bloodstream infection. Endothelial cells form the inner lining of a blood vessel and provide an antithrombotic barrier between the vessel wall and blood. Platelets on the other hand travel throughout the cardiovascular system and respond by aggregating around the site of injury and initiating clot formation. Activation of either of these cells leads to functional dysregulation in the cardiovascular system. In this review, we will illustrate how S. aureus establish intimate interactions with both endothelial cells and platelets leading to cardiovascular dysregulation.
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Affiliation(s)
- Carolina D Garciarena
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
| | - Tony M McHale
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
| | - Rebecca L Watkin
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
| | - Steven W Kerrigan
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
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33
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Lerche CJ, Christophersen LJ, Trøstrup H, Thomsen K, Jensen PØ, Hougen HP, Bundgaard H, Høiby N, Moser C. Low efficacy of tobramycin in experimental Staphylococcus aureus endocarditis. Eur J Clin Microbiol Infect Dis 2015; 34:2349-57. [PMID: 26440039 DOI: 10.1007/s10096-015-2488-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 09/03/2015] [Indexed: 12/31/2022]
Abstract
The empiric treatment of infective endocarditis (IE) varies widely and, in some places, a regimen of penicillin in combination with an aminoglycoside is administered. The increasing incidence of Staphylococcus aureus IE, poor tissue penetration by aminoglycosides and low frequency of penicillin-susceptible S. aureus may potentially lead to functional tobramycin monotherapy. Therefore, this study aimed to evaluate tobramycin monotherapy in an experimental S. aureus IE rat model. Catheter-induced IE at the aortic valves were established with S. aureus (NCTC 8325-4) and rats were randomised into untreated (n = 22) or tobramycin-treated (n = 13) groups. The treatment group received tobramycin once-daily. Animals were evaluated at 1 day post infection (DPI), 2 DPI or 3 DPI. Quantitative bacteriology and cytokine expression were measured for valves, myocardium and serum. A decrease of bacterial load was observed in valves and the spleens of the treated (n = 6) compared to the untreated group at 2 DPI (n = 8) (p ≤ 0.02 and p ≤ 0.01, respectively), but not at 3 DPI (n = 7). Quantitative bacteriology in the myocardium was not different between the groups. Keratinocyte-derived chemokine (KC) in the aortic valves was significantly reduced at 2 DPI in the tobramycin-treated group (p ≤ 0.03). However, the expression of interleukin (IL)-1b, IL-6 and granulocyte-colony stimulating factor (G-CSF) in the valves was not different between the two groups. In the myocardium, a significant reduction in IL-1b was observed at 2 DPI (p ≤ 0.001) but not at 3 DPI. Tobramycin as functional monotherapy only reduced bacterial load and inflammation transiently, and was insufficient in most cases of S. aureus IE.
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Affiliation(s)
- C J Lerche
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries vej 22, 2100, Copenhagen, Denmark.
| | - L J Christophersen
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries vej 22, 2100, Copenhagen, Denmark
| | - H Trøstrup
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries vej 22, 2100, Copenhagen, Denmark
| | - K Thomsen
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries vej 22, 2100, Copenhagen, Denmark
| | - P Ø Jensen
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries vej 22, 2100, Copenhagen, Denmark
| | - H P Hougen
- Department of Forensic Medicine, University of Copenhagen, Copenhagen, Denmark
| | - H Bundgaard
- Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - N Høiby
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries vej 22, 2100, Copenhagen, Denmark.,Institute of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - C Moser
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries vej 22, 2100, Copenhagen, Denmark
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34
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In Silico Sub-unit Hexavalent Peptide Vaccine Against an Staphylococcus aureus Biofilm-Related Infection. Int J Pept Res Ther 2015. [DOI: 10.1007/s10989-015-9489-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Rozemeijer W, Fink P, Rojas E, Jones CH, Pavliakova D, Giardina P, Murphy E, Liberator P, Jiang Q, Girgenti D, Peters RPH, Savelkoul PHM, Jansen KU, Anderson AS, Kluytmans J. Evaluation of approaches to monitor Staphylococcus aureus virulence factor expression during human disease. PLoS One 2015; 10:e0116945. [PMID: 25719409 PMCID: PMC4342157 DOI: 10.1371/journal.pone.0116945] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/17/2014] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus aureus is a versatile pathogen of medical significance, using multiple virulence factors to cause disease. A prophylactic S. aureus 4-antigen (SA4Ag) vaccine comprising capsular polysaccharide (types 5 and 8) conjugates, clumping factor A (ClfA) and manganese transporter C (MntC) is under development. This study was designed to characterize S. aureus isolates recovered from infected patients and also to investigate approaches for examining expression of S. aureus vaccine candidates and the host response during human infection. Confirmation of antigen expression in different disease states is important to support the inclusion of these antigens in a prophylactic vaccine. Hospitalized patients with diagnosed S. aureus wound (27) or bloodstream (24) infections were enrolled. Invasive and nasal carriage S. aureus isolates were recovered and characterized for genotypic diversity. S. aureus antigen expression was evaluated directly by real-time, quantitative, reverse-transcriptase PCR (qRT-PCR) analysis and indirectly by serology using a competitive Luminex immunoassay. Study isolates were genotypically diverse and all had the genes encoding the antigens present in the SA4Ag vaccine. S. aureus nasal carriage was detected in 55% of patients, and in those subjects 64% of the carriage isolates matched the invasive strain. In swab samples with detectable S. aureus triosephosphate isomerase housekeeping gene expression, RNA transcripts encoding the S. aureus virulence factors ClfA, MntC, and capsule polysaccharide were detected by qRT-PCR. Antigen expression was indirectly confirmed by increases in antibody titer during the course of infection from acute to convalescent phase. Demonstration of bacterial transcript expression together with immunological response to the SA4Ag antigens in a clinically relevant patient population provides support for inclusion of these antigens in a prophylactic vaccine.
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Affiliation(s)
| | - Pamela Fink
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Eduardo Rojas
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - C. Hal Jones
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Danka Pavliakova
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Peter Giardina
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Ellen Murphy
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Paul Liberator
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Qin Jiang
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Douglas Girgenti
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | | | | | - Kathrin U. Jansen
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
| | - Annaliesa S. Anderson
- Pfizer Vaccine Research and Development, Pearl River, New York, United States of America
- * E-mail:
| | - Jan Kluytmans
- VU University Medical Center, Amsterdam, The Netherlands
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36
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Hsu RB, Lin FY. Methicillin Resistance and Risk Factors for Embolism inStaphylococcus aureusInfective Endocarditis. Infect Control Hosp Epidemiol 2015; 28:860-6. [PMID: 17564990 DOI: 10.1086/518727] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Accepted: 12/07/2006] [Indexed: 11/03/2022]
Abstract
Objective.Infective endocarditis caused byStaphylococcus aureusis an ominous prognosis associated with a high prevalence of embolic episodes and neurological involvement. Whether methicillin resistance decreases the risk of embolism in infective endocarditis is unclear. We sought to assess the association between methicillin resistance and risk factors for embolism in S.aureusinfective endocarditis.Design.Retrospective chart review. Data from patients with infective endocarditis due to methicillin-resistantS. aureus werecompared with data from patients with endocarditis due to methicillin-susceptibleS. aureus.Logistic regression was used to identify independent risk factors for embolism.Setting.A 2,000-bed, university-affiliated tertiary care hospital.Patients.Between 1995 and 2005, 123 patients withS. aureusinfective endocarditis were included in the study. There were 74 male patients and 49 female patients, with a median age of 54 years (range, 0-89 years).Results.Of 123 infections, 30 (24%) were nosocomial infections, and 14 (11%) were prosthetic valve infections. Of 123S. aureusisolates, 48 (39%) were methicillin resistant. In total, embolism occurred in 45 (37%) of these patients: pulmonary embolism in 22 (18%), cerebral embolism in 21 (17%), and peripheral embolism in 6 (5%). The independent risk factors for an embolism were injection drug use, presence of a cardiac vegetation with a size of 10 mm or greater, and absence of nosocomial infection. For 83 patients with aortic or mitral infective endocarditis, independent risk factors for an embolism were the presence of a cardiac vegetation with a size of 10 mm or greater and endocarditis due to methicillin-susceptibleS. aureus.Overall, in-hospital death occurred for 32 (26%) of 123 Patients. Methicillin-resistant infection was not an independent risk factor for death.Conclusions.Methicillin-resistant S.aureusinfection was associated with decreased risk of embolism in left-side endocarditis, but was not associated with in-hospital death.
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Affiliation(s)
- Ron-Bin Hsu
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan, Republic of China
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37
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Hanses F, Roux C, Dunman PM, Salzberger B, Lee JC. Staphylococcus aureus gene expression in a rat model of infective endocarditis. Genome Med 2014; 6:93. [PMID: 25392717 PMCID: PMC4228149 DOI: 10.1186/s13073-014-0093-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 10/20/2014] [Indexed: 01/04/2023] Open
Abstract
Background Diabetes mellitus is a frequent underlying comorbidity in patients with Staphylococcus aureus endocarditis, and it represents a risk factor for complications and a negative outcome. The pathogenesis of staphylococcal endocardial infections in diabetic hosts has been poorly characterized, and little is known about S. aureus gene expression in endocardial vegetations. Methods We utilized a rat model of experimental S. aureus endocarditis to compare the pathogenesis of staphylococcal infection in diabetic and nondiabetic hosts and to study the global S. aureus transcriptome in endocardial vegetations in vivo. Results Diabetic rats had higher levels of bacteremia and larger endocardial vegetations than nondiabetic control animals. Microarray analyses revealed that 61 S. aureus genes were upregulated in diabetic rats, and the majority of these bacterial genes were involved in amino acid and carbohydrate metabolism. When bacterial gene expression in vivo (diabetic or nondiabetic endocardial vegetations) was compared to in vitro growth conditions, higher in vivo expression of genes encoding toxins and proteases was observed. Additionally, genes involved in the production of adhesins, capsular polysaccharide, and siderophores, as well as in amino acid and carbohydrate transport and metabolism, were upregulated in endocardial vegetations. To test the contribution of selected upregulated genes to the pathogenesis of staphylococcal endocarditis, isogenic deletion mutants were utilized. A mutant defective in production of the siderophore staphyloferrin B was attenuated in the endocarditis model, whereas the virulence of a surface adhesin (ΔsdrCDE) mutant was similar to that of the parental S. aureus strain. Conclusions Our results emphasize the relevance of diabetes mellitus as a risk factor for infectious endocarditis and provide a basis for understanding gene expression during staphylococcal infections in vivo. Electronic supplementary material The online version of this article (doi:10.1186/s13073-014-0093-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Frank Hanses
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA ; Department of Internal Medicine I, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93049 Germany
| | - Christelle Roux
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY 14642 USA
| | - Paul M Dunman
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY 14642 USA
| | - Bernd Salzberger
- Department of Internal Medicine I, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93049 Germany
| | - Jean C Lee
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115 USA
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38
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Jaglic Z, Desvaux M, Weiss A, Nesse LL, Meyer RL, Demnerova K, Schmidt H, Giaouris E, Sipailiene A, Teixeira P, Kačániová M, Riedel CU, Knøchel S. Surface adhesins and exopolymers of selected foodborne pathogens. MICROBIOLOGY-SGM 2014; 160:2561-2582. [PMID: 25217529 DOI: 10.1099/mic.0.075887-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of bacteria to bind different compounds and to adhere to biotic and abiotic surfaces provides them with a range of advantages, such as colonization of various tissues, internalization, avoidance of an immune response, and survival and persistence in the environment. A variety of bacterial surface structures are involved in this process and these promote bacterial adhesion in a more or less specific manner. In this review, we will focus on those surface adhesins and exopolymers in selected foodborne pathogens that are involved mainly in primary adhesion. Their role in biofilm development will also be considered when appropriate. Both the clinical impact and the implications for food safety of such adhesion will be discussed.
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Affiliation(s)
- Zoran Jaglic
- Veterinary Research Institute, Brno, Czech Republic
| | - Mickaël Desvaux
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Agnes Weiss
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | | | - Rikke L Meyer
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Katerina Demnerova
- Institute of Chemical Technology, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Technicka 5, Prague, 166 28, Czech Republic
| | - Herbert Schmidt
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, 81400 Myrina, Lemnos Island, Greece
| | | | - Pilar Teixeira
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal
| | | | - Christian U Riedel
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Susanne Knøchel
- Department of Food Science, University of Copenhagen, Rolighedsvej 30, Frederiksberg C 1958, Denmark
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Children with invasive Staphylococcus aureus disease exhibit a potently neutralizing antibody response to the cytotoxin LukAB. Infect Immun 2013; 82:1234-42. [PMID: 24379282 DOI: 10.1128/iai.01558-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Despite the importance of Staphylococcus aureus as a common invasive bacterial pathogen, the humoral response to infection remains inadequately defined, particularly in children. The purpose of this study was to assess the humoral response to extracellular staphylococcal virulence factors, including the bicomponent leukotoxins, which are critical for the cytotoxicity of S. aureus toward human neutrophils. Children with culture-proven S. aureus infection were prospectively enrolled and stratified by disease type. Fifty-three children were enrolled in the study, of which 90% had invasive disease. Serum samples were obtained during the acute (within 48 h) and convalescent (4 to 6 weeks postinfection) phases, at which point both IgG titers against S. aureus exotoxins were determined, and the functionality of the generated antibodies was evaluated. Molecular characterization of clinical isolates was also performed. We observed a marked rise in antibody titer from acute-phase to convalescent-phase sera for LukAB, the most recently described S. aureus bicomponent leukotoxin. LukAB production by the isolates was strongly correlated with cytotoxicity in vitro, and sera containing anti-LukAB antibodies potently neutralized cytotoxicity. Antibodies to S. aureus antigens were detectable in healthy pediatric controls but at much lower titers than in sera from infected subjects. The discovery of a high-titer, neutralizing antibody response to LukAB during invasive infections suggests that this toxin is produced in vivo and that it elicits a functional humoral response.
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Waller AK, Sage T, Kumar C, Carr T, Gibbins JM, Clarke SR. Staphylococcus aureus lipoteichoic acid inhibits platelet activation and thrombus formation via the Paf receptor. J Infect Dis 2013; 208:2046-57. [PMID: 23911710 PMCID: PMC3836464 DOI: 10.1093/infdis/jit398] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Impaired healing is common in wounds infected with the major human pathogen Staphylococcus aureus, although the underlying mechanisms are poorly understood. Here, we show that S. aureus lipoteichoic acid (LTA) inhibits platelet aggregation caused by physiological agonists and S. aureus and reduced platelet thrombus formation in vitro. The presence of D-alanine on LTA is necessary for the full inhibitory effect. Inhibition of aggregation was blocked using a monoclonal anti-platelet activating factor receptor (PafR) antibody and Ginkgolide B, a well-defined PafR antagonist, demonstrating that the LTA inhibitory signal occurs via PafR. Using a cyclic AMP (cAMP) assay and a Western blot for phosphorylated VASP, we determined that cAMP levels increase upon platelet incubation with LTA, an effect which inhibits platelet activation. This was blocked when platelets were preincubated with Ginkgolide B. Furthermore, LTA reduced hemostasis in a mouse tail-bleed assay.
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Oprea M, Antohe F. Reverse-vaccinology strategy for designing T-cell epitope candidates for Staphylococcus aureus endocarditis vaccine. Biologicals 2013; 41:148-53. [PMID: 23582120 DOI: 10.1016/j.biologicals.2013.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/12/2013] [Accepted: 03/15/2013] [Indexed: 11/30/2022] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen causing various inflammatory diseases from skin and tissue local infections, to serious life threatening infections including endocarditis. Experimental models for endocarditis demonstrated that virulence factors of S. aureus, that are very important in infection of heart vegetations, are surface proteins which promote bacterial adherence. Until now, efforts to develop effective vaccines against S. aureus were unsuccessful, partly due to the fact that different vaccine formulations have targeted mainly B-cell immunity. Reverse vaccinology is applied here, in order to identify potential vaccine epitope candidates. The basic epitopes prediction strategy relied on detection of a common antigenic 9-mer epitope meant to be able to stimulate both the B-cell and T-cell mediated immunity. Ten surface exposed proteins were chosen for antigenicity testing. Using a web-based system, five T-cell epitopes corresponding to fibronectin binding protein A (FDFTLSNNV and YVDGYIETI), collagen adhesin (FSINYKTKI), serine-rich adhesin for platelets (LTFDSTNNT) and elastin binding protein (FAMDKSHPE) were selected as potential vaccine candidates. Epitopes sequences were found to be conserved among the different S. aureus genomes screened from NCBI GenBank. In vitro and in vivo immunological tests will be performed in order to validate the suitability of the epitopes for vaccine development.
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Affiliation(s)
- Mihaela Oprea
- Molecular Epidemiology Laboratory, Cantacuzino National Institute of Research-Development for Microbiology and Immunology, Splaiul Independentei Street, No. 103, 050096 Bucharest, Romania.
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Resveratrol stimulates sphingosine-1-phosphate signaling of cathelicidin production. J Invest Dermatol 2013; 133:1942-9. [PMID: 23856934 PMCID: PMC3753186 DOI: 10.1038/jid.2013.133] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 02/07/2013] [Accepted: 02/26/2013] [Indexed: 12/26/2022]
Abstract
We recently discovered a regulatory mechanism that stimulates production of the multifunctional antimicrobial peptide, cathelicidin antimicrobial peptide (CAMP). In response to subtoxic levels of ER stress, increased sphingosine-1-phosphate (S1P) production activates an NFκB→C/EBPα dependent pathway that enhances CAMP production in cultured human keratinocytes. Since the multifunctional stilbenoid compound, resveratrol (RESV), increases ceramide (Cer) levels, a precursor of S1P, we hypothesized and assessed whether RESV could exploit the same pathway to regulate CAMP production. Accordingly, RESV significantly increased Cer and S1P levels in cultured keratinocytes, paralleled by increased CAMP mRNA/protein expression. Furthermore, topical RESV also increased murine CAMP mRNA/protein expression in mouse skin. Conversely, blockade of Cer→sphingosine→S1P metabolic conversion, with specific inhibitors of ceramidase or sphingosine kinase, attenuated the expected RESV-mediated increase in CAMP expression. The RESV-induced increase in CAMP expression required both NF-κB and C/EBPα transactivation. Moreover, conditioned media from keratinocyte treated with RESV significantly suppressed Staphylococcus aureus growth. Finally, topical RESV, if not coapplied with a specific inhibitor of sphingosine kinase, blocked Staphylococcus aureus invasion into murine skin. These results demonstrate that the dietary stilbenoid, RESV, stimulates S1P signaling of CAMP production through an NF-κB→C/EBPα-dependent mechanism, leading to enhanced antimicrobial defense against exogenous microbial pathogens.
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Påhlman LI, Mörgelin M, Kasetty G, Olin AI, Schmidtchen A, Herwald H. Antimicrobial activity of fibrinogen and fibrinogen-derived peptides--a novel link between coagulation and innate immunity. Thromb Haemost 2013; 109:930-9. [PMID: 23467586 DOI: 10.1160/th12-10-0739] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 02/17/2013] [Indexed: 12/21/2022]
Abstract
Fibrinogen is a key player in the blood coagulation system, and is upon activation with thrombin converted into fibrin that subsequently forms a fibrin clot. In the present study, we investigated the role of fibrinogen in the early innate immune response. Here we show that the viability of fibrinogen-binding bacteria is affected in human plasma activated with thrombin. Moreover, we found that the peptide fragment GHR28 released from the β-chain of fibrinogen has antimicrobial activity against bacteria that bind fibrinogen to their surface, whereas non-binding strains are unaffected. Notably, bacterial killing was detected in Group A Streptococcus bacteria entrapped in a fibrin clot, suggesting that fibrinogen and coagulation is involved in the early innate immune system to quickly wall off and neutralise invading pathogens.
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Affiliation(s)
- L I Påhlman
- Department of Clinical Sciences, Lund, Division of Infection Medicine, Lund University, Tornavägen 10, Lund, Sweden.
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Genetic elimination of the binding motif on fibrinogen for the S. aureus virulence factor ClfA improves host survival in septicemia. Blood 2013; 121:1783-94. [PMID: 23299312 DOI: 10.1182/blood-2012-09-453894] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Fibrinogen can support host antimicrobial containment/clearance mechanisms, yet selected pathogens appear to benefit from host procoagulants to drive bacterial virulence. Here, we explored the hypothesis that host fibrin(ogen), on balance, supports Staphylococcus aureus infection in the context of septicemia. Survival studies following intravenous infection in control and fibrinogen-deficient mice established the overall utility of host fibrin(ogen) to S. aureus virulence. Complementary studies in mice expressing mutant forms of fibrinogen-retaining clotting function, but lacking either the bacterial ClfA (Fibγ(Δ5)) binding motif or the host leukocyte integrin receptor αMβ2 (Fibγ(390-396A)) binding motif, revealed the preeminent importance of the bacterial ClfA-fibrin(ogen) interaction in determining host survival. Studies of mice lacking platelets or the platelet integrin receptor subunit αIIb established that the survival benefits observed in Fibγ(Δ5) mice were largely independent of platelet αIIbβ3-mediated engagement of fibrinogen. Fibγ(Δ5) mice exhibited reduced bacterial burdens in the hearts and kidneys, a blunted host proinflammatory cytokine response, diminished microscopic tissue damage, and significantly diminished plasma markers of cardiac and other organ damage. These findings indicate that host fibrin(ogen) and bacterial ClfA are dual determinants of virulence and that therapeutic interventions at the level of fibrinogen could be advantageous in S. aureus septicemia.
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Use of a human-like low-grade bacteremia model of experimental endocarditis to study the role of Staphylococcus aureus adhesins and platelet aggregation in early endocarditis. Infect Immun 2012; 81:697-703. [PMID: 23250949 DOI: 10.1128/iai.01030-12] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Animal models of infective endocarditis (IE) induced by high-grade bacteremia revealed the pathogenic roles of Staphylococcus aureus surface adhesins and platelet aggregation in the infection process. In humans, however, S. aureus IE possibly occurs through repeated bouts of low-grade bacteremia from a colonized site or intravenous device. Here we used a rat model of IE induced by continuous low-grade bacteremia to explore further the contributions of S. aureus virulence factors to the initiation of IE. Rats with aortic vegetations were inoculated by continuous intravenous infusion (0.0017 ml/min over 10 h) with 10(6) CFU of Lactococcus lactis pIL253 or a recombinant L. lactis strain expressing an individual S. aureus surface protein (ClfA, FnbpA, BCD, or SdrE) conferring a particular adhesive or platelet aggregation property. Vegetation infection was assessed 24 h later. Plasma was collected at 0, 2, and 6 h postinoculation to quantify the expression of tumor necrosis factor (TNF), interleukin 1α (IL-1α), IL-1β, IL-6, and IL-10. The percentage of vegetation infection relative to that with strain pIL253 (11%) increased when binding to fibrinogen was conferred on L. lactis (ClfA strain) (52%; P = 0.007) and increased further with adhesion to fibronectin (FnbpA strain) (75%; P < 0.001). Expression of fibronectin binding alone was not sufficient to induce IE (BCD strain) (10% of infection). Platelet aggregation increased the risk of vegetation infection (SdrE strain) (30%). Conferring adhesion to fibrinogen and fibronectin favored IL-1β and IL-6 production. Our results, with a model of IE induced by low-grade bacteremia, resembling human disease, extend the essential role of fibrinogen binding in the initiation of S. aureus IE. Triggering of platelet aggregation or an inflammatory response may contribute to or promote the development of IE.
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A novel role of a lipid species, sphingosine-1-phosphate, in epithelial innate immunity. Mol Cell Biol 2012; 33:752-62. [PMID: 23230267 DOI: 10.1128/mcb.01103-12] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A variety of external perturbations can induce endoplasmic reticulum (ER) stress, followed by stimulation of epithelial cells to produce an innate immune element, the cathelicidin antimicrobial peptide (CAMP). ER stress also increases production of the proapoptotic lipid ceramide and its antiapoptotic metabolite, sphingosine-1-phosphate (S1P). We demonstrate here that S1P mediates ER stress-induced CAMP generation. Cellular ceramide and S1P levels rose in parallel with CAMP levels following addition of either exogenous cell-permeating ceramide (C2Cer), which increases S1P production, or thapsigargin (an ER stressor), applied to cultured human skin keratinocytes or topically to mouse skin. Knockdown of S1P lyase, which catabolizes S1P, enhanced ER stress-induced CAMP production in cultured cells and mouse skin. These and additional inhibitor studies show that S1P is responsible for ER stress-induced upregulation of CAMP expression. Increased CAMP expression is likely mediated via S1P-dependent NF-κB-C/EBPα activation. Finally, lysates of both ER-stressed and S1P-stimulated cells blocked growth of virulent Staphylococcus aureus in vitro, and topical C2Cer and LL-37 inhibited invasion of Staphylococcus aureus into murine skin. These studies suggest that S1P generation resulting in increased CAMP production comprises a novel regulatory mechanism of epithelial innate immune responses to external perturbations, pointing to a new therapeutic approach to enhance antimicrobial defense.
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Sibbald MJJB, Yang XM, Tsompanidou E, Qu D, Hecker M, Becher D, Buist G, van Dijl JM. Partially overlapping substrate specificities of staphylococcal group A sortases. Proteomics 2012; 12:3049-62. [PMID: 22930668 DOI: 10.1002/pmic.201200144] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 07/12/2012] [Accepted: 07/27/2012] [Indexed: 11/10/2022]
Abstract
Sortases catalyze the covalent attachment of proteins with a C-terminal LPxTG motif to the cell walls of Gram-positive bacteria. Here, we show that deletion of the srtA genes of Staphylococcus aureus and Staphylococcus epidermidis resulted in the dislocation of several LPxTG proteins from the cell wall to the growth medium. Nevertheless, proteomics and Western blotting analyses revealed that substantial amounts of the identified proteins remained cell wall bound through noncovalent interactions. The protein dislocation phenotypes of srtA mutants of S. aureus and S. epidermidis were reverted by ectopic expression of srtA genes of either species. Interestingly, S. epidermidis contains a second sortase A, which was previously annotated as ``SrtC.'' Ectopic expression of this SrtC in srtA mutant cells reverted the dislocation of some, but not all, cell wall associated proteins. Similarly, defects in biofilm formation were reverted by ectopic expression of SrtC in some, but not all, tested srtA mutant strains. Finally, overexpression of SrtA resulted in increased levels of biofilm formation in some tested strains. Taken together, these findings show that the substrate specificities of SrtA and SrtC overlap partially, and that sortase levels may be limiting for biofilm formation in some staphylococci.
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Affiliation(s)
- Mark J J B Sibbald
- Department of Medical Microbiology, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
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Anderson AS, Miller AA, Donald RGK, Scully IL, Nanra JS, Cooper D, Jansen KU. Development of a multicomponent Staphylococcus aureus vaccine designed to counter multiple bacterial virulence factors. Hum Vaccin Immunother 2012; 8:1585-94. [PMID: 22922765 PMCID: PMC3601133 DOI: 10.4161/hv.21872] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Staphylococcus aureus is a major cause of healthcare-associated infections and is responsible for a substantial burden of disease in hospitalized patients. Despite increasingly rigorous infection control guidelines, the prevalence and corresponding negative impact of S. aureus infections remain considerable. Difficulties in controlling S. aureus infections as well as the associated treatment costs are exacerbated by increasing rates of resistance to available antibiotics. Despite ongoing efforts over the past 20 years, no licensed S. aureus vaccine is currently available. However, learnings from past clinical failures of vaccine candidates and a better understanding of the immunopathology of S. aureus colonization and infection have aided in the design of new vaccine candidates based on multiple important bacterial pathogenesis mechanisms. This review outlines important considerations in designing a vaccine for the prevention of S. aureus disease in healthcare settings.
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A recombinant clumping factor A-containing vaccine induces functional antibodies to Staphylococcus aureus that are not observed after natural exposure. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:1641-50. [PMID: 22896688 DOI: 10.1128/cvi.00354-12] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Staphylococcus aureus is a Gram-positive pathogen that causes devastating disease and whose pathogenesis is dependent on interactions with host cell factors. Staphylococcal clumping factor A (ClfA) is a highly conserved fibrinogen (Fg)-binding protein and virulence factor that contributes to host tissue adhesion and initiation of infection. ClfA is being investigated as a possible component of a staphylococcal vaccine. We report the development of an Fg-binding assay that is specific for ClfA-mediated binding. Using the assay, we show that despite the presence of anti-ClfA antibodies, human sera from unvaccinated subjects are unable to prevent the binding of S. aureus to an Fg-coated surface. In contrast, antibodies elicited by a recombinant ClfA-containing vaccine were capable of blocking the ClfA-dependent binding of a diverse and clinically relevant collection of staphylococcal strains to Fg. These functional antibodies were also able to displace S. aureus already bound to Fg, suggesting that the ligand-binding activity of ClfA can be effectively neutralized through vaccination.
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