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Doctor A, Zimmerman J, Agus M, Rajasekaran S, Wardenburg JB, Fortenberry J, Zajicek A, Typpo K. Pediatric Multiple Organ Dysfunction Syndrome: Promising Therapies. Pediatr Crit Care Med 2017; 18:S67-S82. [PMID: 28248836 PMCID: PMC5333132 DOI: 10.1097/pcc.0000000000001053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To describe the state of the science, identify knowledge gaps, and offer potential future research questions regarding promising therapies for children with multiple organ dysfunction syndrome presented during the Eunice Kennedy Shriver National Institute of Child Health and Human Development Workshop on Pediatric Multiple Organ Dysfunction Syndrome (March 26-27, 2015). DATA SOURCES Literature review, research data, and expert opinion. STUDY SELECTION Not applicable. DATA EXTRACTION Moderated by an expert from the field, issues relevant to the association of multiple organ dysfunction syndrome with a variety of conditions were presented, discussed, and debated with a focus on identifying knowledge gaps and research priorities. DATA SYNTHESIS Summary of presentations and discussion supported and supplemented by relevant literature. CONCLUSIONS Among critically ill children, multiple organ dysfunction syndrome is relatively common and associated with significant morbidity and mortality. For outcomes to improve, effective therapies aimed at preventing and treating this condition must be discovered and rigorously evaluated. In this article, a number of potential opportunities to enhance current care are highlighted including the need for a better understanding of the pharmacokinetics and pharmacodynamics of medications, the effect of early and optimized nutrition, and the impact of effective glucose control in the setting of multiple organ dysfunction syndrome. Additionally, a handful of the promising therapies either currently being implemented or developed are described. These include extracorporeal therapies, anticytokine therapies, antitoxin treatments, antioxidant approaches, and multiple forms of exogenous steroids. For the field to advance, promising therapies and other therapies must be assessed in rigorous manner and implemented accordingly.
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Affiliation(s)
- Allan Doctor
- Departments of Pediatrics (Critical Care Medicine) and Biochemistry, Washington University in Saint Louis
| | - Jerry Zimmerman
- Department of Pediatrics (Critical Care Medicine), University of Washington, Seattle, WA
| | - Michael Agus
- Department of Pediatrics (Critical Care Medicine), Harvard University, Boston, MA
| | - Surender Rajasekaran
- Department of Pediatrics (Critical Care Medicine), Michigan State University, Grand Rapids, MI
| | | | - James Fortenberry
- Department of Pediatrics (Critical Care Medicine), Emory University, Atlanta, GA
| | - Anne Zajicek
- Obstetric and Pediatric Pharmacology and Therapeutics Branch, NICHD
| | - Katri Typpo
- Department of Pediatrics (Critical Care Medicine), University of Arizona, Phoenix, AZ
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Thänert R, Goldmann O, Beineke A, Medina E. Host-inherent variability influences the transcriptional response of Staphylococcus aureus during in vivo infection. Nat Commun 2017; 8:14268. [PMID: 28155859 PMCID: PMC5296661 DOI: 10.1038/ncomms14268] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/14/2016] [Indexed: 12/11/2022] Open
Abstract
The rise of antibiotic resistance calls for alternative strategies to treat bacterial infections. One attractive strategy is to directly target bacterial virulence factors with anti-virulence drugs. The expression of virulence traits by pathogens is, however, not constitutive but rather induced by the level of stress encountered within the host. Here we use dual RNA sequencing (RNA-seq) to show that intrinsic variability in the level of host resistance greatly affects the pathogen's transcriptome in vivo. Through analysis of the transcriptional profiles of host and pathogen during Staphylococcus aureus infection of two mouse strains, shown to be susceptible (A/J) or resistant (C57BL/6) to the pathogen, we demonstrate that the expression of virulence factors is dependent on the encountered host resistance. We furthermore provide evidence that this dependence strongly influences the efficacy of anti-virulence strategies, highlighting a potential limitation for the implementation of these strategies. Drugs inhibiting virulence factors of bacterial pathogens are under development. Here, Thänert et al. analyse the transcriptomes of host and pathogen during Staphylococcus aureus infection of two mouse strains, and show that virulence determinants are differentially expressed in different mouse strains.
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Affiliation(s)
- Robert Thänert
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Oliver Goldmann
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Andreas Beineke
- Institute for Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Eva Medina
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
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Structure and Function of the Two-Component Cytotoxins of Staphylococcus aureus - Learnings for Designing Novel Therapeutics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 966:15-35. [PMID: 28455832 DOI: 10.1007/5584_2016_200] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Staphylococcus aureus can produce up to five different bi-component cytotoxins: two gamma-hemolysins HlgAB and HlgCB, and leukocidins SF-PV (Panton Valentine leukocidin), ED (LukED) and GH (LukGH, also called LukAB). Their major function in S. aureus pathogenesis is to evade innate immunity by attacking phagocytic cells and to support bacterial growth by lysing red blood cells. The five cytotoxins display different levels of amino acid sequence conservation (30-82%), but all form a remarkably similar beta-barrel type pore structure (greatly resembling the mono-component toxin alpha-hemolysin) that inserts into the target cell membrane leading to necrotic cell death. This review provides an overview of the culmination of decades of research on the structure of these toxins, their unique sequence and structural features that helps to explain the observed functional differences, such as toxin potency towards different cell types and species, receptor specificity and formation of functional non-cognate toxin pairs. The vast knowledge accumulated in this field supports novel approaches and the design of therapeutics targeting these cytotoxins to tame virulence and fight S. aureus infections.
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104
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Safety, Tolerability, and Pharmacokinetics of MEDI4893, an Investigational, Extended-Half-Life, Anti-Staphylococcus aureus Alpha-Toxin Human Monoclonal Antibody, in Healthy Adults. Antimicrob Agents Chemother 2016; 61:AAC.01020-16. [PMID: 27795368 PMCID: PMC5192133 DOI: 10.1128/aac.01020-16] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/03/2016] [Indexed: 12/18/2022] Open
Abstract
MEDI4893 is an investigational immunoglobulin G1(κ) monoclonal antibody that specifically binds to and neutralizes alpha-toxin, a key Staphylococcus aureus virulence factor. A triple-amino-acid substitution, M252Y/S254T/T256E, was engineered into the MEDI4893 Fc region to extend its serum half-life. A phase 1, double-blind, dose escalation study was designed to evaluate the safety, tolerability, pharmacokinetics, anti-alpha-toxin-neutralizing activity, and antidrug antibody (ADA) response of MEDI4893 following a single intravenous infusion in healthy adults 18 to 65 years of age. Thirty-three subjects were randomly assigned to receive MEDI4893 at 225 mg (n = 3), 750 mg (n = 3), 2,250 mg (n = 8), or 5,000 mg (n = 12) or placebo (n = 7) and were followed for 360 days. Adverse events were mild or moderate in severity; none were serious. The MEDI4893 peak serum concentration increased dose proportionally from 77.2 μg/ml (225-mg dose) to 1,784 μg/ml (5,000-mg dose). The area under the concentration-time curve from 0 to 360 days also increased dose proportionally, from 4,840 μg · day/ml (225-mg dose) to 91,493 μg · day/ml (5,000-mg dose), indicating linear pharmacokinetics. MEDI4893's terminal half-life was estimated to be 80 to 112 days, which is approximately 4-fold longer than the half-lives of other human immunoglobulin G antibodies. The alpha-toxin-neutralizing activity in serum correlated highly with the MEDI4893 concentrations in serum. Three adults transiently tested positive for ADA on day 151, but this did not have an impact on MEDI4893 serum concentrations or the MEDI4893 safety profile; no subjects exhibited serum ADA at the study end. These data support the continued development of MEDI4893 for the prevention of S. aureus-mediated pneumonia. (This study has been registered at ClinicalTrials.gov under identifier NCT02296320.)
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105
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Cohen TS, Hilliard JJ, Jones-Nelson O, Keller AE, O'Day T, Tkaczyk C, DiGiandomenico A, Hamilton M, Pelletier M, Wang Q, Diep BA, Le VTM, Cheng L, Suzich J, Stover CK, Sellman BR. Staphylococcus aureus α toxin potentiates opportunistic bacterial lung infections. Sci Transl Med 2016; 8:329ra31. [PMID: 26962155 DOI: 10.1126/scitranslmed.aad9922] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Broad-spectrum antibiotic use may adversely affect a patient's beneficial microbiome and fuel cross-species spread of drug resistance. Although alternative pathogen-specific approaches are rationally justified, a major concern for this precision medicine strategy is that co-colonizing or co-infecting opportunistic bacteria may still cause serious disease. In a mixed-pathogen lung infection model, we find that the Staphylococcus aureus virulence factor α toxin potentiates Gram-negative bacterial proliferation, systemic spread, and lethality by preventing acidification of bacteria-containing macrophage phagosomes, thereby reducing effective killing of both S. aureus and Gram-negative bacteria. Prophylaxis or early treatment with a single α toxin neutralizing monoclonal antibody prevented proliferation of co-infecting Gram-negative pathogens and lethality while also promoting S. aureus clearance. These studies suggest that some pathogen-specific, antibody-based approaches may also work to reduce infection risk in patients colonized or co-infected with S. aureus and disparate drug-resistant Gram-negative bacterial opportunists.
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Affiliation(s)
- Taylor S Cohen
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Jamese J Hilliard
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Omari Jones-Nelson
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Ashley E Keller
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Terrence O'Day
- Department of Translational Science, MedImmune, Gaithersburg, MD 20878, USA
| | - Christine Tkaczyk
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | | | - Melissa Hamilton
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Mark Pelletier
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Qun Wang
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Binh An Diep
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA. Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Vien T M Le
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Lily Cheng
- Department of Translational Science, MedImmune, Gaithersburg, MD 20878, USA
| | - JoAnn Suzich
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - C Kendall Stover
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Bret R Sellman
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA.
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106
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Liu B, Park S, Thompson CD, Li X, Lee JC. Antibodies to Staphylococcus aureus capsular polysaccharides 5 and 8 perform similarly in vitro but are functionally distinct in vivo. Virulence 2016; 8:859-874. [PMID: 27936346 DOI: 10.1080/21505594.2016.1270494] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The capsular polysaccharide (CP) produced by Staphylococcus aureus is a virulence factor that allows the organism to evade uptake and killing by host neutrophils. Polyclonal antibodies to the serotype 5 (CP5) and type 8 (CP8) capsular polysaccharides are opsonic and protect mice against experimental bacteremia provoked by encapsulated staphylococci. Thus, passive immunotherapy using CP antibodies has been considered for the prevention or treatment of invasive antibiotic-resistant S. aureus infections. In this report, we generated monoclonal antibodies (mAbs) against S. aureus CP5 or CP8. Backbone specific mAbs reacted with native and O-deacetylated CPs, whereas O-acetyl specific mAbs reacted only with native CPs. Reference strains of S. aureus and a selection of clinical isolates reacted by colony immunoblot with the CP5 and CP8 mAbs in a serotype-specific manner. The mAbs mediated in vitro CP type-specific opsonophagocytic killing of S. aureus strains, and mice passively immunized with CP5 mAbs were protected against S. aureus bacteremia. Neither CP8-specific mAbs or polyclonal antibodies protected mice against bacteremia provoked by serotype 8 S. aureus clinical isolates, although these same antibodies did protect against a serotype 5 S. aureus strain genetically engineered to produce CP8. We detected soluble CP8 in culture supernatants of serotype 8 clinical isolates and in the plasma of infected animals. Serotype 5 S. aureus released significantly less soluble CP5 in vitro and in vivo. The release of soluble CP8 by S. aureus may contribute to the inability of CP8 vaccines or antibodies to protect against serotype 8 staphylococcal infections.
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Affiliation(s)
- Bo Liu
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
| | - Saeyoung Park
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
| | - Christopher D Thompson
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
| | - Xue Li
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA.,b Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing , China
| | - Jean C Lee
- a Division of Infectious Diseases , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA
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107
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Liu Y, Shi D, Guo Y, Li M, Zha Y, Wang Q, Wang J. Dracorhodin Perochlorate attenuates Staphylococcus aureus USA300 virulence by decreasing α-toxin expression. World J Microbiol Biotechnol 2016; 33:17. [PMID: 27900629 DOI: 10.1007/s11274-016-2129-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/14/2016] [Indexed: 01/08/2023]
Abstract
α-Toxin, a pore-forming toxin secreted by most Staphylococcus aureus, plays critical role in the pathogenesis associated with various infectious diseases. The USA300 which is a major international epidemic methicilin-resisrant S. aureus has spread rapidly to multiple countries and become an emerging public health concern. In this study, the in vitro efficacy of Dracorhodin Perochlorate (DP) against USA300 virulence was evaluated. Using susceptibility testing, immunoblots, rabbit blood haemolytic assay and real-time RT-PCR, we observed that the α-toxin production was decreased when USA300 was co-cultured with different sub-inhibitory concentration of DP. Further, the protective effect of DP against USA300-mediated injury of human alveolar epithelial cells (A549) and MH-S cells was evaluated by cytotoxicity assays, and the result revealed that DP, at final concentration of 16 µg/ml, is a potent antagonist for USA300-mediated cell damage. Importantly, those beneficial effects might partially correlate with hla and RNAIII suppression by DP, leading to the inhibition of α-toxin production in culture supernatant. Overall, these results suggest that DP could attenuate the virulence of USA300 by decreasing α-toxin production without inhibiting bacterial growth, and this compound may represent an ideal candidate for the development of anti-virulence agent combating S. aureus infection.
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Affiliation(s)
- Yumin Liu
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.,College of Animal Science and Technology, Changchun University of Science and Technology, Changchun, 130600, China
| | - Dongxue Shi
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Yan Guo
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Meng Li
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Yonghong Zha
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Quankai Wang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.
| | - Jianfeng Wang
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
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108
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Cohen TS, Jones-Nelson O, Hotz M, Cheng L, Miller LS, Suzich J, Stover CK, Sellman BR. S. aureus blocks efferocytosis of neutrophils by macrophages through the activity of its virulence factor alpha toxin. Sci Rep 2016; 6:35466. [PMID: 27739519 PMCID: PMC5064327 DOI: 10.1038/srep35466] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/28/2016] [Indexed: 12/17/2022] Open
Abstract
Bacterial pneumonia, such as those caused by Staphylococcus aureus, is associated with an influx of inflammatory neutrophils into the lung tissue and airways. Regulation and clearance of recruited neutrophils is essential for preventing tissue damage by “friendly fire”, a responsibility of macrophages in a process called efferocytosis. We hypothesized that S. aureus impairs efferocytosis by alveolar macrophages (AMs) through the activity of the secreted virulence factor alpha toxin (AT), which has been implicated in altering the antimicrobial function of AMs. Infection of mice lacking AMs resulted in significantly increased numbers of neutrophils in the lung, while clearance of neutrophils delivered intranasally into uninfected mice was reduced in AM depleted animals. In vitro, sublytic levels of AT impaired uptake of apoptotic neutrophils by purified AMs. In vivo, the presence of AT reduced uptake of neutrophils by AMs. Differential uptake of neutrophils was not due to changes in either the CD47/CD172 axis or CD36 levels. AT significantly reduced lung expression of CCN1 and altered AM surface localization of DD1α, two proteins known to influence efferocytosis. We conclude that AT may contribute to tissue damage during S. aureus pneumonia by inhibiting the ability of AM to clear neutrophils at the site of infection.
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Affiliation(s)
- Taylor S Cohen
- Department of Infectious Disease, Medimmune, LLC One MedImmune Way, Gaithersburg, MD 20878, USA
| | - Omari Jones-Nelson
- Department of Infectious Disease, Medimmune, LLC One MedImmune Way, Gaithersburg, MD 20878, USA
| | - Meghan Hotz
- Department of Infectious Disease, Medimmune, LLC One MedImmune Way, Gaithersburg, MD 20878, USA
| | - Lily Cheng
- Department of Translational Science, Medimmune, LLC One MedImmune Way, Gaithersburg, MD 20878, USA
| | - Lloyd S Miller
- Department of Dermatology, John Hopkins University School of Medicine, Baltimore MD 21231, USA
| | - JoAnn Suzich
- Department of Infectious Disease, Medimmune, LLC One MedImmune Way, Gaithersburg, MD 20878, USA
| | - C Kendall Stover
- Department of Infectious Disease, Medimmune, LLC One MedImmune Way, Gaithersburg, MD 20878, USA
| | - Bret R Sellman
- Department of Infectious Disease, Medimmune, LLC One MedImmune Way, Gaithersburg, MD 20878, USA
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109
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Critical Role of Alpha-Toxin and Protective Effects of Its Neutralization by a Human Antibody in Acute Bacterial Skin and Skin Structure Infections. Antimicrob Agents Chemother 2016; 60:5640-8. [PMID: 27401576 DOI: 10.1128/aac.00710-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/01/2016] [Indexed: 12/20/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) causes large-scale epidemics of acute bacterial skin and skin structure infections (ABSSSI) within communities across the United States. Animal models that reproduce ABSSSI as they occur in humans are urgently needed to test new therapeutic strategies. Alpha-toxin plays a critical role in a variety of staphylococcal infection models in mice, but its role in the pathogenesis of ABSSSI remains to be elucidated in rabbits, which are similar to humans in their susceptibility to S. aureus superantigens and certain bicomponent pore-forming leukocidins. We report here a new rabbit model of ABSSSI and show that those infected with a mutant deficient in expression of alpha-toxin (Δhla) developed a small dermonecrotic lesion, whereas those infected with isogenic USA300 MRSA wild-type or complemented Δhla strains developed ABSSSI that mimic the severe infections that occur in humans, including the large central dermonecrotic core surrounded by erythema, induration, and marked subcutaneous hemorrhage. More importantly, immunoprophylaxis with MEDI4893*, an anti-alpha-toxin human monoclonal antibody, significantly reduced the severity of disease caused by a USA300 wild-type strain to that caused by the Δhla mutant, indicating that this toxin could be completely neutralized during infection. Thus, this study illustrates a potential high standard for the development of new immunotherapeutic agents in which a toxin-neutralizing antibody provides protection to the same degree achieved with a toxin gene knockout. When MEDI4893* was administered as adjunctive therapy with a subtherapeutic dose of linezolid, the combination was significantly more efficacious than either agent alone in reducing the severity of ABSSSI.
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110
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Improved Protection in a Rabbit Model of Community-Associated Methicillin-Resistant Staphylococcus aureus Necrotizing Pneumonia upon Neutralization of Leukocidins in Addition to Alpha-Hemolysin. Antimicrob Agents Chemother 2016; 60:6333-40. [PMID: 27527081 DOI: 10.1128/aac.01213-16] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/06/2016] [Indexed: 12/31/2022] Open
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), especially the USA300 pulsotype, is a frequent cause of skin and soft tissue infections and severe pneumonia. Despite appropriate antibiotic treatment, complications are common and pneumonia is associated with high mortality. S. aureus strains express multiple cytotoxins, including alpha-hemolysin (Hla) and up to five bicomponent leukocidins that specifically target phagocytic cells for lysis. CA-MRSA USA300 strains carry the genes for all six cytotoxins. Species specificity of the leukocidins greatly contributes to the ambiguity regarding their role in S. aureus pathogenesis. We performed a comparative analysis of the leukocidin susceptibility of human, rabbit, and mouse polymorphonuclear leukocytes (PMNs) to assess the translational value of mouse and rabbit S. aureus models. We found that mouse PMNs were largely resistant to LukSF-PV, HlgAB, and HlgCB and susceptible only to LukED, whereas rabbit and human PMNs were highly sensitive to all these cytotoxins. In the rabbit pneumonia model with a USA300 CA-MRSA strain, passive immunization with a previously identified human monoclonal antibody (MAb), Hla-F#5, which cross-neutralizes Hla, LukSF-PV, HlgAB, HlgCB, and LukED, provided full protection, whereas an Hla-specific MAb was only partially protective. In the mouse USA300 CA-MRSA pneumonia model, both types of antibodies demonstrated full protection, suggesting that Hla, but not leukocidin(s), is the principal virulence determinant in mice. As the rabbit recapitulates the high susceptibility to leukocidins characteristic of humans, this species represents a valuable model for assessing novel, cytotoxin-targeting anti-S. aureus therapeutic approaches.
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111
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Yu KOA, Randolph AG, Agan AA, Yip WK, Truemper EJ, Weiss SL, Ackerman KG, Schwarz AJ, Giuliano JS, Hall MW, Bubeck Wardenburg J. Staphylococcus aureus α-Toxin Response Distinguishes Respiratory Virus-Methicillin-Resistant S. aureus Coinfection in Children. J Infect Dis 2016; 214:1638-1646. [PMID: 27651418 DOI: 10.1093/infdis/jiw441] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/12/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Development of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia after a respiratory viral infection is frequently fatal in children. In mice, S. aureus α-toxin directly injures pneumocytes and increases mortality, whereas α-toxin blockade mitigates disease. The role of α-toxin in pediatric staphylococcal-viral coinfection is unclear. METHODS We enrolled children across 34 North American pediatric intensive care units with acute respiratory failure and suspected influenza virus infection. Serial serum anti-α-toxin antibody titers and functional α-toxin neutralization capacity were compared across children coinfected with MRSA or methicillin-susceptible S. aureus (MSSA) and control children infected with influenza virus only. MRSA isolates were tested for α-toxin production and lethality in a murine pneumonia model. RESULTS Influenza virus was identified in 22 of 25 children with MRSA coinfection (9 died) and 22 patients with MSSA coinfection (all survived). Initial α-toxin-specific antibody titers were similar, compared with those in the 13 controls. In patients with serial samples, only MRSA-coinfected patients showed time-dependent increases in anti-α-toxin titer and functional neutralization capacity. MRSA α-toxin production from patient isolates correlated with initial serologic titers and with mortality in murine pneumonia. CONCLUSIONS These data implicate α-toxin as a relevant antigen in severe pediatric MRSA pneumonia associated with respiratory viral infection, supporting a potential role for toxin-neutralizing therapy.
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Affiliation(s)
| | - Adrienne G Randolph
- Department of Anesthesia, Perioperative, and Pain Medicine, Boston Children's Hospital.,Departments of Anaesthesia and Pediatrics, Harvard Medical School
| | - Anna A Agan
- Department of Anesthesia, Perioperative, and Pain Medicine, Boston Children's Hospital.,Departments of Anaesthesia and Pediatrics, Harvard Medical School
| | - Wai-Ki Yip
- Department of Biostatistics, Harvard T. H. Chan School of Public Health.,Department of Biostatistics and Computational Biology, Dana Farber Cancer Institute, Boston, Massachusetts
| | | | - Scott L Weiss
- Department of Pediatrics, Children's Hospital of Philadelphia, Pennsylvania
| | - Kate G Ackerman
- Department of Pediatrics, Golisano Children's Hospital, Rochester, New York
| | - Adam J Schwarz
- Department of Pediatrics, Children's Hospital of Orange County, California
| | - John S Giuliano
- Department of Pediatrics, Yale-New Haven Children's Hospital, Connecticut
| | - Mark W Hall
- Department of Pediatrics, Nationwide Children's Hospital, Columbus, Ohio
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112
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Staphylococcus aureus Alpha-Toxin Is Conserved among Diverse Hospital Respiratory Isolates Collected from a Global Surveillance Study and Is Neutralized by Monoclonal Antibody MEDI4893. Antimicrob Agents Chemother 2016; 60:5312-21. [PMID: 27324766 PMCID: PMC4997823 DOI: 10.1128/aac.00357-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/14/2016] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus infections lead to an array of illnesses ranging from mild skin infections to serious diseases, such endocarditis, osteomyelitis, and pneumonia. Alpha-toxin (Hla) is a pore-forming toxin, encoded by the hla gene, that is thought to play a key role in S. aureus pathogenesis. A monoclonal antibody targeting Hla, MEDI4893, is in clinical development for the prevention of S. aureus ventilator-associated pneumonia (VAP). The presence of the hla gene and Hla protein in 994 respiratory isolates collected from patients in 34 countries in Asia, Europe, the United States, Latin America, the Middle East, Africa, and Australia was determined. Hla levels were correlated with the geographic location, age of the subject, and length of stay in the hospital. hla gene sequence analysis was performed, and mutations were mapped to the Hla crystal structure. S. aureus supernatants containing Hla variants were tested for susceptibility or resistance to MEDI4893. The hla gene was present and Hla was expressed in 99.0% and 83.2% of the isolates, respectively, regardless of geographic region, hospital locale, or age of the subject. More methicillin-susceptible than methicillin-resistant isolates expressed Hla (86.9% versus 78.8%; P = 0.0007), and S. aureus isolates from pediatric patients expressed the largest amounts of Hla. Fifty-seven different Hla subtypes were identified, and 91% of the isolates encoded an Hla subtype that was neutralized by MED4893. This study demonstrates that Hla is conserved in diverse S. aureus isolates from around the world and is an attractive target for prophylactic monoclonal antibody (MAb) or vaccine development.
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113
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The SAATELLITE and EVADE Clinical Studies Within the COMBACTE Consortium: A Public–Private Collaborative Effort in Designing and Performing Clinical Trials for Novel Antibacterial Drugs to Prevent Nosocomial Pneumonia: Table 1. Clin Infect Dis 2016; 63 Suppl 2:S46-51. [DOI: 10.1093/cid/ciw245] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Targeting Alpha Toxin and ClfA with a Multimechanistic Monoclonal-Antibody-Based Approach for Prophylaxis of Serious Staphylococcus aureus Disease. mBio 2016; 7:mBio.00528-16. [PMID: 27353753 PMCID: PMC4937210 DOI: 10.1128/mbio.00528-16] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Staphylococcus aureus produces numerous virulence factors, each contributing different mechanisms to bacterial pathogenesis in a spectrum of diseases. Alpha toxin (AT), a cytolytic pore-forming toxin, plays a key role in skin and soft tissue infections and pneumonia, and a human anti-AT monoclonal antibody (MAb), MEDI4893*, has been shown to reduce disease severity in dermonecrosis and pneumonia infection models. However, interstrain diversity and the complex pathogenesis of S. aureus bloodstream infections suggests that MEDI4893* alone may not provide adequate protection against S. aureus sepsis. Clumping factor A (ClfA), a fibrinogen binding protein, is an important virulence factor facilitating S. aureus bloodstream infections. Herein, we report on the identification of a high-affinity anti-ClfA MAb, 11H10, that inhibits ClfA binding to fibrinogen, prevents bacterial agglutination in human plasma, and promotes opsonophagocytic bacterial killing (OPK). 11H10 prophylaxis reduced disease severity in a mouse bacteremia model and was dependent on Fc effector function and OPK. Additionally, prophylaxis with 11H10 in combination with MEDI4893* provided enhanced strain coverage in this model and increased survival compared to that obtained with the individual MAbs. The MAb combination also reduced disease severity in murine dermonecrosis and pneumonia models, with activity similar to that of MEDI4893* alone. These results indicate that an MAb combination targeting multiple virulence factors provides benefit over a single MAb neutralizing one virulence mechanism by providing improved efficacy, broader strain coverage, and protection against multiple infection pathologies. Alternative strategies to broad-spectrum antibiotics are required to combat the antibiotic resistance epidemic. Previous attempts at active or passive immunization against Staphylococcus aureus targeting single antigens have failed in clinical trials despite positive preclinical data. To provide broad disease and isolate coverage, an effective immunization strategy likely must target multiple virulence mechanisms of the pathogen. Herein, we tested a multimechanistic MAb combination targeting alpha toxin (AT) and clumping factor A (ClfA) that neutralizes AT-mediated cytotoxicity, blocks fibrinogen binding by ClfA, prevents bacterial agglutination, targets the bacteria for opsonophagocytic killing, and provides broad isolate coverage in a lethal-bacteremia model. Although each MAb alone was effective in bacteremia against some individual isolates, the MAb combination provided improved protection against other isolates. These results illustrate the importance of targeting multiple virulence mechanisms and highlight the potential for an MAb combination targeting AT and ClfA to effectively prevent S. aureus disease.
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115
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Li M, Dai Y, Zhu Y, Fu CL, Tan VY, Wang Y, Wang X, Hong X, Liu Q, Li T, Qin J, Ma X, Fang J, Otto M. Virulence determinants associated with the Asian community-associated methicillin-resistant Staphylococcus aureus lineage ST59. Sci Rep 2016; 6:27899. [PMID: 27296890 PMCID: PMC4906288 DOI: 10.1038/srep27899] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/25/2016] [Indexed: 11/09/2022] Open
Abstract
Understanding virulence is vital for the development of novel therapeutics to target infections with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), which cause an ongoing epidemic in the United States and are on a global rise. However, what defines virulence particularly of global CA-MRSA lineages is poorly understood. Threatening a vast population, the predominant Asian CA-MRSA lineage ST59 is of major epidemiological importance. However, there have been no molecular analyses using defined virulence gene deletion mutants in that lineage as of yet. Here, we compared virulence in skin, lung, and blood infection models of ST59 CA-MRSA isolates with geographically matched hospital-associated MRSA isolates. We selected a representative ST59 CA-MRSA isolate based on toxin expression and virulence characteristics, and produced isogenic gene deletion mutants of important CA-MRSA virulence determinants (α-toxin, PSM α, Agr) in that isolate for in-vitro and in-vivo analyses. Our results demonstrate strongly enhanced virulence of ST59 CA-MRSA over hospital-associated lineages, supporting the notion that enhanced virulence is characteristic for CA-MRSA. Furthermore, they show strong and significant contribution of Agr, α-toxin, and PSMα to pathogenesis of ST59 CA-MRSA skin, lung, and blood infection, emphasizing the value of drug development efforts targeted toward those virulence determinants.
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Affiliation(s)
- Min Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Yingxin Dai
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Yuanjun Zhu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.,Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
| | - Chih-Lung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
| | - Vee Y Tan
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
| | - Yanan Wang
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Xing Wang
- Department of Laboratory Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Xufen Hong
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Qian Liu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Tianming Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Juanxiu Qin
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Xiaowei Ma
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Jingyuan Fang
- Department of Gastroenterology and Hepatology, Renji Hospital, School of Medicine, Shanghai Institute of Digestive Disease, Shanghai Jiaotong University, Shanghai, China
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
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Falcó V, Burgos J, Papiol E, Ferrer R, Almirante B. Investigational drugs in phase I and phase II clincial trials for the treatment of hospital-acquired pneumonia. Expert Opin Investig Drugs 2016; 25:653-65. [PMID: 26998623 DOI: 10.1517/13543784.2016.1168803] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Hospital acquired pneumonia (HAP) is one of the main infections acquired by patients during a stay in hospital. The main issue when dealing with patients with HAP and ventilator associated pneumonia (VAP) is the increasing role of multi-drug resistant organisms (MDROs). AREAS COVERED In this review the authors summarize the actual situation of MDROs as a cause of HAP and VAP. They also review the current treatment options stated in the most important international guidelines. Finally, they focus on the investigational drugs that have reached the phase III stage of development and the novel compounds that are being studied in phase I and II clinical trials. EXPERT OPINION Thanks to their excellent activity against MDROs, drugs in development for the treatment of HAP and VAP can significantly improve the therapeutic options available. In selected patients, the possibility to administer directed therapy with monoclonal antibodies to specific pathogens is an exciting strategy in the fight against widespread resistance.
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Affiliation(s)
- Vicenç Falcó
- a Infectious Diseases Department, University Hospital Vall d'Hebron , Universitat Autònoma de Barcelona , Barcelona , Spain
| | - Joaquin Burgos
- a Infectious Diseases Department, University Hospital Vall d'Hebron , Universitat Autònoma de Barcelona , Barcelona , Spain
| | - Elisabeth Papiol
- b Intensive Care Department, University Hospital Vall d'Hebron , Universitat Autònoma de Barcelona , Barcelona , Spain
| | - Ricard Ferrer
- b Intensive Care Department, University Hospital Vall d'Hebron , Universitat Autònoma de Barcelona , Barcelona , Spain
| | - Benito Almirante
- a Infectious Diseases Department, University Hospital Vall d'Hebron , Universitat Autònoma de Barcelona , Barcelona , Spain
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117
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Kong C, Neoh HM, Nathan S. Targeting Staphylococcus aureus Toxins: A Potential form of Anti-Virulence Therapy. Toxins (Basel) 2016; 8:toxins8030072. [PMID: 26999200 PMCID: PMC4810217 DOI: 10.3390/toxins8030072] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/03/2016] [Accepted: 03/10/2016] [Indexed: 01/01/2023] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen and the leading cause of a wide range of severe clinical infections. The range of diseases reflects the diversity of virulence factors produced by this pathogen. To establish an infection in the host, S. aureus expresses an inclusive set of virulence factors such as toxins, enzymes, adhesins, and other surface proteins that allow the pathogen to survive under extreme conditions and are essential for the bacteria’s ability to spread through tissues. Expression and secretion of this array of toxins and enzymes are tightly controlled by a number of regulatory systems. S. aureus is also notorious for its ability to resist the arsenal of currently available antibiotics and dissemination of various multidrug-resistant S. aureus clones limits therapeutic options for a S. aureus infection. Recently, the development of anti-virulence therapeutics that neutralize S. aureus toxins or block the pathways that regulate toxin production has shown potential in thwarting the bacteria’s acquisition of antibiotic resistance. In this review, we provide insights into the regulation of S. aureus toxin production and potential anti-virulence strategies that target S. aureus toxins.
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Affiliation(s)
- Cin Kong
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia.
| | - Hui-min Neoh
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, 56000 Cheras, Kuala Lumpur, Malaysia.
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia.
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118
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Parker D, Ahn D, Cohen T, Prince A. Innate Immune Signaling Activated by MDR Bacteria in the Airway. Physiol Rev 2016; 96:19-53. [PMID: 26582515 DOI: 10.1152/physrev.00009.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Health care-associated bacterial pneumonias due to multiple-drug resistant (MDR) pathogens are an important public health problem and are major causes of morbidity and mortality worldwide. In addition to antimicrobial resistance, these organisms have adapted to the milieu of the human airway and have acquired resistance to the innate immune clearance mechanisms that normally prevent pneumonia. Given the limited efficacy of antibiotics, bacterial clearance from the airway requires an effective immune response. Understanding how specific airway pathogens initiate and regulate innate immune signaling, and whether this response is excessive, leading to host-induced pathology may guide future immunomodulatory therapy. We will focus on three of the most important causes of health care-associated pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, and review the mechanisms through which an inappropriate or damaging innate immune response is stimulated, as well as describe how airway pathogens cause persistent infection by evading immune activation.
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Affiliation(s)
- Dane Parker
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Danielle Ahn
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Taylor Cohen
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Alice Prince
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
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119
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Parker D, Prince A. A new approach to toxin neutralization in Staphylococcus aureus therapy. EMBO Rep 2016; 17:284-5. [PMID: 26882555 DOI: 10.15252/embr.201642015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Dane Parker
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Alice Prince
- Department of Pediatrics, Columbia University, New York, NY, USA
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120
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Czaplewski L, Bax R, Clokie M, Dawson M, Fairhead H, Fischetti VA, Foster S, Gilmore BF, Hancock REW, Harper D, Henderson IR, Hilpert K, Jones BV, Kadioglu A, Knowles D, Ólafsdóttir S, Payne D, Projan S, Shaunak S, Silverman J, Thomas CM, Trust TJ, Warn P, Rex JH. Alternatives to antibiotics-a pipeline portfolio review. THE LANCET. INFECTIOUS DISEASES 2016; 16:239-51. [PMID: 26795692 DOI: 10.1016/s1473-3099(15)00466-1] [Citation(s) in RCA: 533] [Impact Index Per Article: 66.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 11/06/2015] [Accepted: 11/10/2015] [Indexed: 01/21/2023]
Abstract
Antibiotics have saved countless lives and enabled the development of modern medicine over the past 70 years. However, it is clear that the success of antibiotics might only have been temporary and we now expect a long-term and perhaps never-ending challenge to find new therapies to combat antibiotic-resistant bacteria. A broader approach to address bacterial infection is needed. In this Review, we discuss alternatives to antibiotics, which we defined as non-compound approaches (products other than classic antibacterial agents) that target bacteria or any approaches that target the host. The most advanced approaches are antibodies, probiotics, and vaccines in phase 2 and phase 3 trials. This first wave of alternatives to antibiotics will probably best serve as adjunctive or preventive therapies, which suggests that conventional antibiotics are still needed. Funding of more than £1·5 billion is needed over 10 years to test and develop these alternatives to antibiotics. Investment needs to be partnered with translational expertise and targeted to support the validation of these approaches in phase 2 trials, which would be a catalyst for active engagement and investment by the pharmaceutical and biotechnology industry. Only a sustained, concerted, and coordinated international effort will provide the solutions needed for the future.
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Affiliation(s)
- Lloyd Czaplewski
- Chemical Biology Ventures, Abingdon, Oxfordshire, UK; Abgentis, Edgbaston, Birmingham, UK; Persica Pharmaceuticals, Canterbury, Kent, UK.
| | | | - Martha Clokie
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Mike Dawson
- Novacta Biosystems, Welwyn Garden City, Hertfordshire, UK; Cantab Anti-infectives, Welwyn Garden City, Hertfordshire, UK
| | | | - Vincent A Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, NY, USA
| | - Simon Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK; Absynth Biologics, Liverpool, UK
| | | | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - David Harper
- Evolution Biotechnologies, Ampthill, Bedfordshire, UK
| | - Ian R Henderson
- Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, UK
| | - Kai Hilpert
- Institute of Infection and Immunity, St George's, University of London, London, UK; TiKa Diagnostics, London, UK
| | - Brian V Jones
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK; Queen Victoria Hospital NHS Foundation Trust, East Grinstead, West Sussex, UK
| | - Aras Kadioglu
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - David Knowles
- Absynth Biologics, Liverpool, UK; Procarta Biosystems, Norwich, UK
| | | | - David Payne
- GlaxoSmithKline, Collegeville, Pennsylvania, PA, USA
| | | | - Sunil Shaunak
- Department of Medicine, Imperial College London, London, UK
| | | | - Christopher M Thomas
- Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, UK; Plasgene, Edgbaston, Birmingham, UK
| | - Trevor J Trust
- Pan-Provincial Vaccine Enterprise, Saskatoon, SK, Canada
| | | | - John H Rex
- AstraZeneca, Boston, MA, USA; F2G, Manchester, UK
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121
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Sause WE, Buckley PT, Strohl WR, Lynch AS, Torres VJ. Antibody-Based Biologics and Their Promise to Combat Staphylococcus aureus Infections. Trends Pharmacol Sci 2015; 37:231-241. [PMID: 26719219 DOI: 10.1016/j.tips.2015.11.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 11/26/2022]
Abstract
The growing incidence of serious infections mediated by methicillin-resistant Staphylococcus aureus (MRSA) strains poses a significant risk to public health. This risk is exacerbated by a prolonged void in the discovery and development of truly novel antibiotics and the absence of a vaccine. These gaps have created renewed interest in the use of biologics in the prevention and treatment of serious staphylococcal infections. In this review, we focus on efforts towards the discovery and development of antibody-based biologic agents and their potential as clinical agents in the management of serious S. aureus infections. Recent promising data for monoclonal antibodies (mAbs) targeting anthrax and Ebola highlight the potential of antibody-based biologics as therapeutic agents for serious infections.
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Affiliation(s)
- William E Sause
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Peter T Buckley
- Janssen Research & Development LLC, 1400 McKean Road, Spring House, PA 19477, USA
| | - William R Strohl
- Janssen Research & Development LLC, 1400 McKean Road, Spring House, PA 19477, USA
| | - A Simon Lynch
- Janssen Research & Development LLC, 1400 McKean Road, Spring House, PA 19477, USA.
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
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122
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Sun H, Wei C, Liu B, Jing H, Feng Q, Tong Y, Yang Y, Yang L, Zuo Q, Zhang Y, Zou Q, Zeng H. Induction of systemic and mucosal immunity against methicillin-resistant Staphylococcus aureus infection by a novel nanoemulsion adjuvant vaccine. Int J Nanomedicine 2015; 10:7275-90. [PMID: 26664118 PMCID: PMC4672755 DOI: 10.2147/ijn.s91529] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Gram-positive bacterial pathogen methicillin-resistant Staphylococcus aureus (MRSA) can cause infections in the bloodstream, endocardial tissue, respiratory tract, culture-confirmed skin, or soft tissue. There are currently no effective vaccines, and none are expected to become available in the near future. An effective vaccine capable of eliciting both systemic and mucosal immune responses is also urgently needed. Here, we reported a novel oil-in-water nanoemulsion adjuvant vaccine containing an MRSA recombination protein antigen, Cremophor EL-35® as a surfactant, and propylene glycol as a co-surfactant. This nanoemulsion vaccine, whose average diameter was 31.34±0.49 nm, demonstrated good protein structure integrity, protein specificity, and good stability at room temperature for 1 year. The intramuscular systemic and nasal mucosal immune responses demonstrated that this nanoemulsion vaccine could improve the specific immune responses of immunoglobulin (Ig)G and related subclasses, such as IgG1, IgG2a, and IgG2b, as well as IgA, in the serum after Balb/c mice intramuscular immunization and C57 mice nasal immunization. Furthermore, this nanoemulsion vaccine also markedly enhanced the interferon-γ and interleukin-17A cytokine cell immune response, improved the survival ratio, and reduced bacterial colonization. Taken together, our results show that this novel nanoemulsion vaccine has great potential and is a robust generator of an effective intramuscular systemic and nasal mucosal immune response without the need for an additional adjuvant. Thus, the present study serves as a sound scientific foundation for future strategies in the development of this novel nanoemulsion adjuvant vaccine to enhance both the intramuscular systemic and nasal mucosal immune responses.
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Affiliation(s)
- HongWu Sun
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - Chao Wei
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - BaoShuai Liu
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - HaiMing Jing
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - Qiang Feng
- Department of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, People's Republic of China
| | - YaNan Tong
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - Yun Yang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - LiuYang Yang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - QianFei Zuo
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - Yi Zhang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - QuanMing Zou
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
| | - Hao Zeng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University of Chinese PLA, Chongqing, People's Republic of China
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Kostyanev T, Bonten MJM, O'Brien S, Steel H, Ross S, François B, Tacconelli E, Winterhalter M, Stavenger RA, Karlén A, Harbarth S, Hackett J, Jafri HS, Vuong C, MacGowan A, Witschi A, Angyalosi G, Elborn JS, deWinter R, Goossens H. The Innovative Medicines Initiative's New Drugs for Bad Bugs programme: European public-private partnerships for the development of new strategies to tackle antibiotic resistance. J Antimicrob Chemother 2015; 71:290-5. [PMID: 26568581 DOI: 10.1093/jac/dkv339] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Antibiotic resistance (ABR) is a global public health threat. Despite the emergence of highly resistant organisms and the huge medical need for new drugs, the development of antibacterials has slowed to an unacceptable level worldwide. Numerous government and non-government agencies have called for public-private partnerships and innovative funding mechanisms to address this problem. To respond to this public health crisis, the Innovative Medicines Initiative Joint Undertaking programme has invested more than €660 million, with a goal of matched contributions from the European Commission and the European Federation of Pharmaceutical Industries and Associations, in the development of new antibacterial strategies. The New Drugs for Bad Bugs (ND4BB) programme, an Innovative Medicines Initiative, has the ultimate goal to boost the fight against ABR at every level from basic science and drug discovery, through clinical development to new business models and responsible use of antibiotics. Seven projects have been launched within the ND4BB programme to achieve this goal. Four of them will include clinical trials of new anti-infective compounds, as well as epidemiological studies on an unprecedented scale, which will increase our knowledge of ABR and specific pathogens, and improve the designs of the clinical trials with new investigational drugs. The need for rapid concerted action has driven the funding of seven topics, each of which should add significantly to progress in the fight against ABR. ND4BB unites expertise and provides a platform where the commitment and resources required by all parties are streamlined into a joint public-private partnership initiative of unprecedented scale.
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Affiliation(s)
- T Kostyanev
- Department of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - M J M Bonten
- Julius Center for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - S O'Brien
- Infection Global Medicines Development, AstraZeneca, Macclesfield, Cheshire, UK
| | - H Steel
- Infectious Diseases Therapy Area Unit, GlaxoSmithKline, London, UK
| | - S Ross
- Infectious Diseases Therapy Area Unit, GlaxoSmithKline, London, UK
| | - B François
- Centre Hospitalier Universitaire Dupuytren, Limoges, France
| | - E Tacconelli
- Internal Medicine 1, Infectious Diseases, DZIF-TTU-HAARBI, University Hospital Tübingen, Tübingen, Germany
| | - M Winterhalter
- School of Engineering & Science, Jacobs University Bremen, Bremen, Germany
| | - R A Stavenger
- Antibacterial Discovery Performance Unit, GlaxoSmithKline, Collegeville, PA, USA
| | - A Karlén
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - S Harbarth
- University of Geneva and Faculty of Medicine, Geneva, Switzerland
| | - J Hackett
- Infection Global Medicines Development, AstraZeneca, Gaithersburg, MD, USA
| | | | - C Vuong
- AiCuris GmbH & Co. KG, Wuppertal, Germany
| | - A MacGowan
- Bristol Centre for Antimicrobial Research & Evaluation, Department of Infection Sciences, North Bristol NHS Trust and Public Health England, Bristol, UK
| | - A Witschi
- Basilea Pharmaceutica International Ltd, Basel, Switzerland
| | | | - J S Elborn
- School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - R deWinter
- Julius Center for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - H Goossens
- Department of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium Laboratory of Medical Microbiology, University Hospital Antwerp, Antwerp, Belgium
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124
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Vuong C, Yeh AJ, Cheung GYC, Otto M. Investigational drugs to treat methicillin-resistant Staphylococcus aureus. Expert Opin Investig Drugs 2015; 25:73-93. [PMID: 26536498 DOI: 10.1517/13543784.2016.1109077] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Staphylococcus aureus remains one of the leading causes of morbidity and mortality worldwide. This is to a large extent due to antibiotic-resistant strains, in particular methicillin-resistant S. aureus (MRSA). While the toll of invasive MRSA infections appears to decrease in U.S. hospitals, the rate of community-associated MRSA infections remains constant and there is a surge of MRSA in many other countries, a situation that calls for continuing if not increased efforts to find novel strategies to combat MRSA infections. AREAS COVERED This review provides an overview of current investigational drugs and therapeutic antibodies against S. aureus in early clinical development (up to phase II clinical development). It includes a short description of the mechanism of action and a presentation of microbiological and clinical data. EXPERT OPINION Increased recent antibiotic development efforts and results from pathogenesis research have led to several new antibiotics and therapies, such as anti-virulence drugs, as well as a more informed selection of targets for vaccination efforts against MRSA. This developing portfolio of novel anti-staphylococcal drugs will hopefully provide us with additional and more efficient ways to combat MRSA infections in the near future and prevent us from running out of treatment options, even if new resistances arise.
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Affiliation(s)
- Cuong Vuong
- a Principal Scientist/Laboratory Head, Bacteriology , AiCuris GmbH & Co. KG, Friedrich-Ebert-Str. 475/Geb. 302, 42117 Wuppertal , Germany
| | - Anthony J Yeh
- b Post-baccalaureate IRTA, Laboratory of Bacteriology , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bldg. 33, 1W10, 9000 Rockville Pike, Bethesda , MD 20892 , USA
| | - Gordon Y C Cheung
- c Staff Scientist, National Institute of Allergy and Infectious Diseases , National Institutes of Health, Laboratory of Bacteriology , Bldg. 33, 1W10, 9000 Rockville Pike, Bethesda , MD 20892 , USA
| | - Michael Otto
- d Senior Investigator, National Institute of Allergy and Infectious Diseases , National Institutes of Health, Laboratory of Bacteriology , Bldg. 33, 1W10, 9000 Rockville Pike, Bethesda , MD 20892 , USA
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Rouha H, Badarau A, Visram ZC, Battles MB, Prinz B, Magyarics Z, Nagy G, Mirkina I, Stulik L, Zerbs M, Jägerhofer M, Maierhofer B, Teubenbacher A, Dolezilkova I, Gross K, Banerjee S, Zauner G, Malafa S, Zmajkovic J, Maier S, Mabry R, Krauland E, Wittrup KD, Gerngross TU, Nagy E. Five birds, one stone: neutralization of α-hemolysin and 4 bi-component leukocidins of Staphylococcus aureus with a single human monoclonal antibody. MAbs 2015; 7:243-54. [PMID: 25523282 PMCID: PMC5045134 DOI: 10.4161/19420862.2014.985132] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen associated with high mortality. The emergence of antibiotic resistance and the inability of antibiotics to counteract bacterial cytotoxins involved in the pathogenesis of S. aureus call for novel therapeutic approaches, such as passive immunization with monoclonal antibodies (mAbs). The complexity of staphylococcal pathogenesis and past failures with single mAb products represent considerable barriers for antibody-based therapeutics. Over the past few years, efforts have focused on neutralizing α-hemolysin. Recent findings suggest that the concerted actions of several cytotoxins, including the bi-component leukocidins play important roles in staphylococcal pathogenesis. Therefore, we aimed to isolate mAbs that bind to multiple cytolysins by employing high diversity human IgG1 libraries presented on the surface of yeast cells. Here we describe cross-reactive antibodies with picomolar affinity for α-hemolysin and 4 different bi-component leukocidins that share only ∼26% overall amino acid sequence identity. The molecular basis of cross-reactivity is the recognition of a conformational epitope shared by α-hemolysin and F-components of gamma-hemolysin (HlgAB and HlgCB), LukED and LukSF (Panton-Valentine Leukocidin). The amino acids predicted to form the epitope are conserved and known to be important for cytotoxic activity. We found that a single cross-reactive antibody prevented lysis of human phagocytes, epithelial and red blood cells induced by α-hemolysin and leukocidins in vitro, and therefore had superior effectiveness compared to α-hemolysin specific antibodies to protect from the combined cytolytic effect of secreted S. aureus toxins. Such mAb afforded high levels of protection in murine models of pneumonia and sepsis.
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Key Words
- BLI, biolayer interferometry
- EC50, effective concentration
- Hla, α-hemolysin
- HlgAB and HlgCB, gamma-hemolysins
- IC50, inhibitory concentration
- LukED, leukocidin ED
- LukSF, leukocidin SF
- PMN, polymorphonuclear cells
- RBC, red blood cell
- Staphylococcus aureus
- engineered cross-reactivity
- exotoxins
- in vitro potency
- in vivo efficacy
- mAb, monoclonal antibody
- monoclonal antibody
- toxin neutralization
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126
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Antibacterial monoclonal antibodies: the next generation? Curr Opin Microbiol 2015; 27:78-85. [PMID: 26302478 DOI: 10.1016/j.mib.2015.07.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 07/28/2015] [Accepted: 07/30/2015] [Indexed: 12/21/2022]
Abstract
There is a clear need for renewed efforts to combat the increasing incidence of antibiotic resistance. While the antibiotic resistance epidemic is due in part to the misuse of antibiotics, even proper empiric antibiotic therapy increases the selective pressure and potential for drug-resistance and spread of resistance mechanisms between bacteria. Antibiotic resistance coupled with the detrimental effects of broad-spectrum antibiotics on the healthy microbiome, have led the field to explore pathogen specific antibacterials such as monoclonal antibodies (mAbs). Medical need along with advances in mAb discovery, engineering, and production have driven significant effort developing mAb-based antibacterials. If successful, they will provide physicians with precision weapons to combat bacterial infections and can help prevent a return to a pre-antibiotic era.
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127
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Tong SYC, Davis JS, Eichenberger E, Holland TL, Fowler VG. Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management. Clin Microbiol Rev 2015; 28:603-61. [PMID: 26016486 PMCID: PMC4451395 DOI: 10.1128/cmr.00134-14] [Citation(s) in RCA: 2733] [Impact Index Per Article: 303.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.
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Affiliation(s)
- Steven Y C Tong
- Global and Tropical Health, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Joshua S Davis
- Global and Tropical Health, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Emily Eichenberger
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Thomas L Holland
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Vance G Fowler
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
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128
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MEDI4893* Promotes Survival and Extends the Antibiotic Treatment Window in a Staphylococcus aureus Immunocompromised Pneumonia Model. Antimicrob Agents Chemother 2015; 59:4526-32. [PMID: 25987629 DOI: 10.1128/aac.00510-15] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/11/2015] [Indexed: 12/13/2022] Open
Abstract
Immunocompromised individuals are at increased risk of Staphylococcus aureus pneumonia. Neutralization of alpha-toxin (AT) with the monoclonal antibody (MAb) MEDI4893* protects normal mice from S. aureus pneumonia; however, the effects of the MAb in immunocompromised mice have not been reported. In this study, passive immunization with MEDI4893* increased survival rates and reduced bacterial numbers in the lungs in an immunocompromised murine S. aureus pneumonia model. Lungs from infected mice exhibited alveolar epithelial damage, protein leakage, and bacterial overgrowth, whereas lungs from mice passively immunized with MEDI4893* retained a healthy architecture, with an intact epithelial barrier. Adjunctive therapy or prophylaxis with a subtherapeutic MEDI4893* dose combined with subtherapeutic doses of vancomycin or linezolid improved survival rates, compared with the monotherapies. Furthermore, coadministration of MEDI4893* with vancomycin or linezolid extended the antibiotic treatment window. These data suggest that MAb-mediated neutralization of AT holds promise in strategies for prevention and adjunctive therapy among immunocompromised patients.
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130
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Stulik L, Malafa S, Hudcova J, Rouha H, Henics BZ, Craven DE, Sonnevend AM, Nagy E. α-Hemolysin activity of methicillin-susceptible Staphylococcus aureus predicts ventilator-associated pneumonia. Am J Respir Crit Care Med 2015; 190:1139-48. [PMID: 25303310 DOI: 10.1164/rccm.201406-1012oc] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Colonization of lower airways by Staphylococcus aureus is a risk factor for the development of ventilator-associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP). However, little is known about the virulence factors of methicillin-sensitive and -resistant S. aureus (MSSA and MRSA) that may influence host colonization and progression to VAT and VAP. OBJECTIVES We evaluated MRSA and MSSA endotracheal aspirates (ETA) for genotype and α-hemolysin activity in relation to the development of VAT and VAP. METHODS Serial S. aureus ETA isolates from ventilated patients were analyzed for methicillin resistance, molecular type by Multi-Locus Sequence Typing and spa-typing, and α-hemolysin activity by semiquantitative analysis of hemolysis on sheep blood agar and quantitative measurement of cytolysis of human lung epithelial cells. The virulence of selected strains was assessed in mice by intranasal challenge. MEASUREMENTS AND MAIN RESULTS We detected S. aureus from ETA samples in a quarter of the 231 ventilated patients analyzed; one-third of them developed VAP. VAP patients (n = 15) were mainly infected by MSSA strains (87%), whereas colonized individuals (n = 18) not progressing to disease mainly carried MRSA strains (68%). MSSA isolates from colonized or VAT patients exhibited significantly lower α-hemolysin activity than those from VAP cases; however, no such relationship was found with MRSA strains. α-Hemolysin activity of S. aureus isolates was predictive for virulence in mouse pneumonia model. CONCLUSIONS MSSA strains with strong blood agar hemolysis and high α-hemolysin activity are markers for VAP, but not VAT, and might be considered in differential diagnosis and initiation of therapy.
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131
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Arroliga AC, Velazco JF, Midturi JK, Ghamande SA. Back to the future: α-hemolysin activity on blood agar to predict ventilator-associated pneumonia caused by Staphylococcus aureus. Am J Respir Crit Care Med 2015; 190:1086-8. [PMID: 25398106 DOI: 10.1164/rccm.201410-1886ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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132
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Characterization of alpha-toxin hla gene variants, alpha-toxin expression levels, and levels of antibody to alpha-toxin in hemodialysis and postsurgical patients with Staphylococcus aureus bacteremia. J Clin Microbiol 2014; 53:227-36. [PMID: 25392350 DOI: 10.1128/jcm.02023-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alpha-toxin is a major Staphylococcus aureus virulence factor. This study evaluated potential relationships between in vitro alpha-toxin expression of S. aureus bloodstream isolates, anti-alpha-toxin antibody in serum of patients with S. aureus bacteremia (SAB), and clinical outcomes in 100 hemodialysis and 100 postsurgical SAB patients. Isolates underwent spa typing and hla sequencing. Serum anti-alpha-toxin IgG and neutralizing antibody levels were measured by using an enzyme-linked immunosorbent assay and a red blood cell (RBC)-based hemolysis neutralization assay. Neutralization of alpha-toxin by an anti-alpha-toxin monoclonal antibody (MAb MEDI4893) was tested in an RBC-based lysis assay. Most isolates encoded hla (197/200; 98.5%) and expressed alpha-toxin (173/200; 86.5%). In vitro alpha-toxin levels were inversely associated with survival (cure, 2.19 μg/ml, versus failure, 1.09 μg/ml; P < 0.01). Both neutralizing (hemodialysis, 1.26 IU/ml, versus postsurgical, 0.95; P < 0.05) and IgG (hemodialysis, 1.94 IU/ml, versus postsurgical, 1.27; P < 0.05) antibody levels were higher in the hemodialysis population. Antibody levels were also significantly higher in patients infected with alpha-toxin-expressing S. aureus isolates (P < 0.05). Levels of both neutralizing antibodies and IgG were similar among patients who were cured and those not cured (failures). Sequence analysis of hla revealed 12 distinct hla genotypes, and all genotypic variants were susceptible to a neutralizing monoclonal antibody in clinical development (MEDI4893). These data demonstrate that alpha-toxin is highly conserved in clinical S. aureus isolates. Higher in vitro alpha-toxin levels were associated with a positive clinical outcome. Although patients infected with alpha-toxin-producing S. aureus exhibited higher anti-alpha-toxin antibody levels, these levels were not associated with a better clinical outcome in this study.
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133
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O’Rourke JP, Daly SM, Triplett KD, Peabody D, Chackerian B, Hall PR. Development of a mimotope vaccine targeting the Staphylococcus aureus quorum sensing pathway. PLoS One 2014; 9:e111198. [PMID: 25379726 PMCID: PMC4224382 DOI: 10.1371/journal.pone.0111198] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 09/29/2014] [Indexed: 02/06/2023] Open
Abstract
A major hurdle in vaccine development is the difficulty in identifying relevant target epitopes and then presenting them to the immune system in a context that mimics their native conformation. We have engineered novel virus-like-particle (VLP) technology that is able to display complex libraries of random peptide sequences on a surface-exposed loop in the coat protein without disruption of protein folding or VLP assembly. This technology allows us to use the same VLP particle for both affinity selection and immunization, integrating the power of epitope discovery and epitope mimicry of traditional phage display with the high immunogenicity of VLPs. Previously, we showed that using affinity selection with our VLP platform identifies linear epitopes of monoclonal antibodies and subsequent immunization generates the proper antibody response. To test if our technology could identify immunologic mimotopes, we used affinity selection on a monoclonal antibody (AP4-24H11) that recognizes the Staphylococcus aureus autoinducing peptide 4 (AIP4). AIP4 is a secreted eight amino acid, cyclized peptide produced from the S. aureus accessory gene regulator (agrIV) quorum-sensing operon. The agr system coordinates density dependent changes in gene expression, leading to the upregulation of a host of virulence factors, and passive transfer of AP4-24H11 protects against S. aureus agrIV-dependent pathogenicity. In this report, we identified a set of peptides displayed on VLPs that bound with high specificity to AP4-24H11. Importantly, similar to passive transfer with AP4-24H11, immunization with a subset of these VLPs protected against pathogenicity in a mouse model of S. aureus dermonecrosis. These data are proof of principle that by performing affinity selection on neutralizing antibodies, our VLP technology can identify peptide mimics of non-linear epitopes and that these mimotope based VLP vaccines provide protection against pathogens in relevant animal models.
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Affiliation(s)
- John P. O’Rourke
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, NM, United States of America
- * E-mail: (JPO); (PH)
| | - Seth M. Daly
- Department of Pharmaceutical Sciences, University of New Mexico School of Medicine, Albuquerque, NM United States of America
| | - Kathleen D. Triplett
- Department of Pharmaceutical Sciences, University of New Mexico School of Medicine, Albuquerque, NM United States of America
| | - David Peabody
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, NM, United States of America
| | - Bryce Chackerian
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, NM, United States of America
| | - Pamela R. Hall
- Department of Pharmaceutical Sciences, University of New Mexico School of Medicine, Albuquerque, NM United States of America
- * E-mail: (JPO); (PH)
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134
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Anti-alpha-toxin monoclonal antibody and antibiotic combination therapy improves disease outcome and accelerates healing in a Staphylococcus aureus dermonecrosis model. Antimicrob Agents Chemother 2014; 59:299-309. [PMID: 25348518 DOI: 10.1128/aac.03918-14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Alpha-toxin (AT) is a major virulence determinant in Staphylococcus aureus skin and soft tissue infection models. We previously demonstrated that prophylactic administration of 2A3, an AT-neutralizing monoclonal antibody (MAb), prevents S. aureus disease in a mouse dermonecrosis model by neutralizing AT-mediated tissue necrosis and immune evasion. In the present study, MEDI4893*, an affinity-optimized version of 2A3, was characterized for therapeutic activity in the dermonecrosis model as a single agent and in combination with two frontline antibiotics, vancomycin and linezolid. MEDI4893* postinfection therapy was found to exhibit a therapeutic treatment window similar to that for linezolid but longer than that for vancomycin. Additionally, when combined with either vancomycin or linezolid, MEDI4893* resulted in reduced tissue damage, increased neutrophil and macrophage infiltration and abscess formation, and accelerated healing relative to those with the antibiotic monotherapies. These data suggest that AT neutralization with a potent MAb holds promise for both prophylaxis and adjunctive therapy with antibiotics and may be a valuable addition to currently available options for the treatment of S. aureus skin and soft tissue infections.
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135
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Yeaman MR, Filler SG, Schmidt CS, Ibrahim AS, Edwards JE, Hennessey JP. Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus. Front Immunol 2014; 5:463. [PMID: 25309545 PMCID: PMC4176462 DOI: 10.3389/fimmu.2014.00463] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/10/2014] [Indexed: 12/22/2022] Open
Abstract
Recent perspectives forecast a new paradigm for future “third generation” vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high-priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologs found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that (1) afford protective efficacy; (2) target an epitope from one organism that contributes to protective immunity against another; (3) cross-protect against multiple pathogens occupying a common anatomic or immunological niche; and/or (4) overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre-clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in pre-clinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3) where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target S. aureus.
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Affiliation(s)
- Michael R Yeaman
- Department of Medicine, David Geffen School of Medicine at UCLA , Los Angeles, CA , USA ; Division of Infectious Diseases, Harbor-UCLA Medical Center , Torrance, CA , USA ; Division of Molecular Medicine, Harbor-UCLA Medical Center , Torrance, CA , USA ; St. John's Cardiovascular Research Center, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , USA
| | - Scott G Filler
- Department of Medicine, David Geffen School of Medicine at UCLA , Los Angeles, CA , USA ; Division of Infectious Diseases, Harbor-UCLA Medical Center , Torrance, CA , USA ; St. John's Cardiovascular Research Center, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , USA
| | | | - Ashraf S Ibrahim
- Department of Medicine, David Geffen School of Medicine at UCLA , Los Angeles, CA , USA ; Division of Infectious Diseases, Harbor-UCLA Medical Center , Torrance, CA , USA ; St. John's Cardiovascular Research Center, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , USA
| | - John E Edwards
- Department of Medicine, David Geffen School of Medicine at UCLA , Los Angeles, CA , USA ; Division of Infectious Diseases, Harbor-UCLA Medical Center , Torrance, CA , USA ; St. John's Cardiovascular Research Center, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center , Torrance, CA , USA
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136
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Hartmann T, Baronian G, Nippe N, Voss M, Schulthess B, Wolz C, Eisenbeis J, Schmidt-Hohagen K, Gaupp R, Sunderkötter C, Beisswenger C, Bals R, Somerville GA, Herrmann M, Molle V, Bischoff M. The catabolite control protein E (CcpE) affects virulence determinant production and pathogenesis of Staphylococcus aureus. J Biol Chem 2014; 289:29701-11. [PMID: 25193664 DOI: 10.1074/jbc.m114.584979] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Carbon metabolism and virulence determinant production are often linked in pathogenic bacteria, and several regulatory elements have been reported to mediate this linkage in Staphylococcus aureus. Previously, we described a novel protein, catabolite control protein E (CcpE) that functions as a regulator of the tricarboxylic acid cycle. Here we demonstrate that CcpE also regulates virulence determinant biosynthesis and pathogenesis. Specifically, deletion of ccpE in S. aureus strain Newman revealed that CcpE affects transcription of virulence factors such as capA, the first gene in the capsule biosynthetic operon; hla, encoding α-toxin; and psmα, encoding the phenol-soluble modulin cluster α. Electrophoretic mobility shift assays demonstrated that CcpE binds to the hla promoter. Mice challenged with S. aureus strain Newman or its isogenic ΔccpE derivative revealed increased disease severity in the ΔccpE mutant using two animal models; an acute lung infection model and a skin infection model. Complementation of the mutant with the ccpE wild-type allele restored all phenotypes, demonstrating that CcpE is negative regulator of virulence in S. aureus.
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Affiliation(s)
- Torsten Hartmann
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Grégory Baronian
- the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier 2, CNRS, UMR 5235, 34090 Montpellier, France
| | - Nadine Nippe
- the Institute of Immunology, University of Münster, 48149 Münster, Germany
| | - Meike Voss
- the Department of Internal Medicine V-Pulmonology, Allergology and Critical Care Medicine, Saarland University Medical Centre, 66421 Homburg/Saar, Germany
| | - Bettina Schulthess
- the Institute of Medical Microbiology, University of Zürich, 8006 Zürich, Switzerland
| | - Christiane Wolz
- the Institute of Medical Microbiology and Hygiene, University Hospital of Tübingen, 72076 Tübingen, Germany
| | - Janina Eisenbeis
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Kerstin Schmidt-Hohagen
- the Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Rosmarie Gaupp
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Cord Sunderkötter
- the Department of Dermatology, University of Münster, 48149 Münster, Germany, and
| | - Christoph Beisswenger
- the Department of Internal Medicine V-Pulmonology, Allergology and Critical Care Medicine, Saarland University Medical Centre, 66421 Homburg/Saar, Germany
| | - Robert Bals
- the Department of Internal Medicine V-Pulmonology, Allergology and Critical Care Medicine, Saarland University Medical Centre, 66421 Homburg/Saar, Germany
| | - Greg A Somerville
- the School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska 68583-0903
| | - Mathias Herrmann
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Virginie Molle
- the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier 2, CNRS, UMR 5235, 34090 Montpellier, France
| | - Markus Bischoff
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany,
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137
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Chen Y, Yeh AJ, Cheung GYC, Villaruz AE, Tan VY, Joo HS, Chatterjee SS, Yu Y, Otto M. Basis of virulence in a Panton-Valentine leukocidin-negative community-associated methicillin-resistant Staphylococcus aureus strain. J Infect Dis 2014; 211:472-80. [PMID: 25139021 DOI: 10.1093/infdis/jiu462] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Community-associated (CA) infections with methicillin-resistant Staphylococcus aureus (MRSA) are on a global rise. However, analysis of virulence characteristics has been limited almost exclusively to the US endemic strain USA300. CA-MRSA strains that do not produce Panton-Valentine leukocidin (PVL) have not been investigated on a molecular level. Therefore, we analyzed virulence determinants in a PVL-negative CA-MRSA strain, ST72, from Korea. Genome-wide analysis identified 3 loci that are unique to that strain, but did not affect virulence. In contrast, phenol-soluble modulins (PSMs) and the global virulence regulator Agr strongly affected lysis of neutrophils and erythrocytes, while α-toxin and Agr had a major impact on in vivo virulence. Our findings substantiate the general key roles these factors play in CA-MRSA virulence. However, our analyses also showed noticeable differences to strain USA300, inasmuch as α-toxin emerged as a much more important factor than PSMs in experimental skin infection caused by ST72.
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Affiliation(s)
- Yan Chen
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Anthony J Yeh
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Amer E Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Vee Y Tan
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Som S Chatterjee
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
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138
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Scully IL, Liberator PA, Jansen KU, Anderson AS. Covering all the Bases: Preclinical Development of an Effective Staphylococcus aureus Vaccine. Front Immunol 2014; 5:109. [PMID: 24715889 PMCID: PMC3970019 DOI: 10.3389/fimmu.2014.00109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/04/2014] [Indexed: 01/19/2023] Open
Abstract
A key aspect of the pathogenesis of the Gram positive bacterium Staphylococcus aureus is its ability to rapidly adapt to the host environment during the course of an infection. To successfully establish infection, the organism deploys a variety of survival and immune evasion strategies, ranging from the acquisition of essential nutrients and expression of adhesins, which promote colonization and survival, to the elaboration of virulence factors such as capsule, which aids host immune evasion. The ability of S. aureus to deploy different virulence factors must be taken into account for S. aureus vaccine design. Here, we present a strategy for designing an effective vaccine against S. aureus disease by evaluating vaccine candidate performance in multiple in vivo models targeted to mimic aspects of human disease, and by co-development of functional in vitro immunoassays that measure the neutralization of relevant S. aureus virulence factors.
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Affiliation(s)
- Ingrid L Scully
- Pfizer Vaccine Research and Development Unit , Pearl River, NY , USA
| | - Paul A Liberator
- Pfizer Vaccine Research and Development Unit , Pearl River, NY , USA
| | - Kathrin U Jansen
- Pfizer Vaccine Research and Development Unit , Pearl River, NY , USA
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