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https://www.readbyqxmd.com/read/29100762/staphylococcal-pathogenicity-islands-movers-and-shakers-in-the-genomic-firmament
#1
REVIEW
Richard P Novick, Geeta Ram
The staphylococcal pathogenicity islands (SaPIs) are highly mobile 15kb genomic islands that carry superantigen genes and other virulence factors and are mobilized by helper phages. Helper phages counteract the SaPI repressor to induce the SaPI replication cycle, resulting in encapsidation in phage like particles, enabling high frequency transfer. The SaPIs split from a protophage lineage in the distant past, have evolved a variety of novel and salient features, and have become an invaluable component of the staphylococcal genome...
October 31, 2017: Current Opinion in Microbiology
https://www.readbyqxmd.com/read/29099691/phylogenetic-distribution-and-expression-of-a-penicillin-binding-protein-homologue-ear-and-its-significance-in-virulence-of-staphylococcus-aureus
#2
Vineet K Singh, Robert P Ring, Vijay Aswani, Mary E Stemper, Jennifer Kislow, Zhan Ye, Sanjay K Shukla
PURPOSE: Staphylococcus aureus is an opportunistic human pathogen that can cause serious infections in humans. A plethora of known and putative virulence factors are produced by staphylococci that collectively orchestrate pathogenesis. Ear protein (Escherichia coli ampicillin resistance) in S. aureus is an exoprotein in COL strain, predicted to be a superantigen, and speculated to play roles in antibiotic resistance and virulence. The goal of this study was to determine if expression of ear is modulated by single nucleotide polymorphisms in its promoter and coding sequences and whether this gene plays roles in antibiotic resistance and virulence...
November 3, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/29095152/structure-of-the-staphylococcal-enterotoxin-b-vaccine-candidate-s19-showing-eliminated-superantigen-activity
#3
Woo Hyeon Jeong, Dong Hyun Song, Gyeung Haeng Hur, Seong Tae Jeong
Four mutations (N23A, Y90A, R110A and F177A) were introduced into S19, a vaccine candidate for staphylococcal enterotoxin B (SEB), resulting in a lower binding affinity towards the T-cell receptor beta chain (TCB) and reducing its superantigen activity. The structure of S19 was solved and was superposed on the native or complex structure of SEB. In the superposition model, mutations that were introduced seemed to reduce the number of hydrogen bonds at the SEB-TCB interface. S19 also displayed an unexpected structural change around the flexible-loop region owing to the Y90A mutation...
November 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
https://www.readbyqxmd.com/read/29056305/exotoxins-and-endotoxins-inducers-of-inflammatory-cytokines
#4
REVIEW
Jean-Marc Cavaillon
Endotoxins and exotoxins are among the most potent bacterial inducers of cytokines. During infectious processes, the production of inflammatory cytokines including tumor necrosis factor (TNF), interleukin-1β (IL-1β), gamma interferon (IFNγ) and chemokines orchestrates the anti-infectious innate immune response. However, an overzealous production, leading up to a cytokine storm, can be deleterious and contributes to mortality consecutive to sepsis or toxic shock syndrome. Endotoxins of Gram-negative bacteria (lipopolysaccharide, LPS) are particularly inflammatory because they generate auto-amplificatory loops after activation of monocytes/macrophages...
October 19, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/29051689/detection-of-newly-defined-superantigenic-toxin-genes-and-coagulase-gene-polymorphism-in-staphylococcus-aureus-isolates
#5
Bareq A Al-Ajealy, Maysa S M Al-Shukri, Hassan S Al-Jumaily
The current study aims to use coagulase (coa) polymorphism gene to identify Staphylococcus aureus isolated from stool samples, evaluate the efficiency of these methods in discriminating variable strains, and compare these subtypes with antibiotypes. A total of 100 specimens were collected from patients in Babylon province, Iraq, between July 2016 and September 2016. Twenty S. aureus strains were isolated and identified using standard laboratory microbiological tests. The bacterial isolates were then examined by coa gene restriction fragment length polymorphism genotyping...
October 2017: Reviews in Medical Microbiology: a Journal of the Pathological Society of Great Britain and Ireland
https://www.readbyqxmd.com/read/28990820/interleukin-2-secretion-by-t-cells-for-detection-of-biologically-active-staphylococcal-enterotoxin-type-e
#6
Reuven Rasooly, Paula Do, Bradley J Hernlem
Staphylococcus aureus is a significant worldwide source of clinical infections and foodborne illnesses; it acts through the synthesis of a group of enterotoxins (SEs) that cause gastroenteritis and also function as superantigens that activate T cells, resulting in massive cytokine production, yielding life-threatening toxicity. It is important that methods for detection and quantification of these toxins respond to their activity and not just the presence of the toxin molecule, which may be deactivated. Traditionally, live animals have been used to test for emesis following administration of the toxin-containing sample...
October 9, 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/28967544/wild-rodents-and-shrews-are-natural-hosts-of-staphylococcus-aureus
#7
Daniel M Mrochen, Daniel Schulz, Stefan Fischer, Kathrin Jeske, Heba El Gohary, Daniela Reil, Christian Imholt, Patricia Trübe, Josef Suchomel, Emilie Tricaud, Jens Jacob, Marta Heroldová, Barbara M Bröker, Birgit Strommenger, Birgit Walther, Rainer G Ulrich, Silva Holtfreter
Laboratory mice are the most commonly used animal model for Staphylococcus aureus infection studies. We have previously shown that laboratory mice from global vendors are frequently colonized with S. aureus. Laboratory mice originate from wild house mice. Hence, we investigated whether wild rodents, including house mice, as well as shrews are naturally colonized with S. aureus and whether S. aureus adapts to the wild animal host. 295 animals of ten different species were caught in different locations over four years (2012-2015) in Germany, France and the Czech Republic...
September 22, 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/28943993/effectiveness-of-a-glycylcycline-antibiotic-for-reducing-the-pathogenicity-of-superantigen-producing-methicillin-resistant-staphylococcus-aureus-in-burn-wounds
#8
Lauren B Nosanov, Daniel Y Jo, Pranay R Randad, Lauren T Moffatt, Bonnie C Carney, Rachel T Ortiz, Jeffrey W Shupp
Objective: Burn-injured patients are highly susceptible to infectious complications, which are often associated with increased morbidity and mortality. Rates of antibiotic resistance have increased, and resistant species such as methicillin-resistant Staphylococcus aureus provide additional challenges in the form of virulence factors. Proteins can disrupt local healing, leading to systemic immune disruption. To optimize outcomes, treatments that reduce pathogenicity must be identified. This study aims to compare a glycylcycline antibiotic-tigecycline-with clindamycin for effectiveness in treating superantigenic methicillin-resistant Staphylococcus aureus in burn wounds...
2017: Eplasty
https://www.readbyqxmd.com/read/28939882/genetic-loci-of-staphylococcus-aureus-associated-with-anti-neutrophil-cytoplasmic-autoantibody-anca-associated-vasculitides
#9
Corinna Glasner, Marcus C de Goffau, Mirjan M van Timmeren, Mirja L Schulze, Benita Jansen, Mehri Tavakol, Willem J B van Wamel, Coen A Stegeman, Cees G M Kallenberg, Jan P Arends, John W Rossen, Peter Heeringa, Jan Maarten van Dijl
The proteinase 3 (PR3)-positive anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) granulomatosis with polyangiitis (GPA) has been associated with chronic nasal S. aureus carriage, which is a risk factor for disease relapse. The present study was aimed at comparing the genetic make-up of S. aureus isolates from PR3-ANCA-positive GPA patients with that of isolates from patients suffering from myeloperoxidase (MPO)-ANCA-positive AAV, and isolates from healthy controls. Based on a DNA microarray-based approach, we show that not only PR3-ANCA-positive GPA patients, but also MPO-ANCA-positive AAV patients mainly carried S...
September 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28934904/clonal-deletion-of-t-cell-repertoires-with-specific-t-cell-receptor-v%C3%AE-chains-by-two-endogenous-superantigens-in-nc-nga-mice
#10
Kozo Ohkusu-Tsukada, Teruyo Tsukada, Kimimasa Takahashi
Superantigens (SAgs) are powerful T-cell stimulatory proteins. Because an atopic dermatitis (AD) model NC/Nga mice had two endogenous SAgs, namely minor lymphocyte-stimulating locus-1(a) (Mls-1(a)) and mouse mammary tumor virus (MMTV)(SHN), SAg-responsive T-cells bearing Vβ5.1, Vβ6, Vβ8.1, Vβ8.2, Vβ8.3, Vβ9, and Vβ11 should be endogenously deleted. Here, we discuss that the endogenous SAgs-expression may be involved in AD-sensitivity in NC/Nga mice.
November 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/28901485/a-novel-non%C3%A2-contact-communication-between-human-keratinocytes-and-t-cells-exosomes-derived-from-keratinocytes-support-superantigen%C3%A2-induced-proliferation-of-resting-t-cells
#11
Xiao-Wei Cai, Rong Zhu, Lei Ran, Yi-Qian Li, Ke Huang, Jing Peng, Wei He, Chun-Li Zhou, Ru-Peng Wang
It is widely accepted that keratinocytes act as non‑professional antigen‑presenting cells and support superantigen‑induced proliferation of resting T cells; however, it remains unknown whether keratinocytes function in situ with T cells via a non‑contact mechanism. The current study used a transwell co‑culture system and demonstrated, for the first time to the best of the authors' knowledge, that HaCaT cells (the human keratinocyte cell line) did induce T cell proliferation via indirect contact. The data further indicated that exosomes, small membrane vesicles that transfer antigens to recipient cells, are also involved in the superantigen‑associated immunity of keratinocytes...
November 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28900005/shocking-superantigens-promote-establishment-of-bacterial-infection
#12
Nikolai Siemens, Anna Norrby-Teglund
No abstract text is available yet for this article.
September 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28892185/prevalence-comorbidities-and-mortality-of-toxic-shock-syndrome-in-united-states-children-and-adults
#13
Mark A Strom, Derek Y Hsu, Jonathan I Silverberg
Toxic Shock Syndrome (TSS) is a superantigen-mediated illness characterized by rash, hypotension and multi-organ dysfunction. The predictors of TSS and related morbidity and mortality are poorly defined. We analyzed data on 61,959,084 hospitalizations from the 2003-2012 Nationwide Inpatient Sample, a 20% stratified sample of US hospitalizations. ICD-9-CM coding was used to identify 4,491 hospitalizations with a diagnosis of TSS. Incidence, in-hospital mortality rate, comorbidities, length of stay and costs of care due to TSS were determined...
September 11, 2017: Microbiology and Immunology
https://www.readbyqxmd.com/read/28880920/the-staphylococcus-aureus-superantigen-selx-is-a-bifunctional-toxin-that-inhibits-neutrophil-function
#14
Stephen W Tuffs, David B A James, Jovanka Bestebroer, Amy C Richards, Mariya I Goncheva, Marie O'Shea, Bryan A Wee, Keun Seok Seo, Patrick M Schlievert, Andreas Lengeling, Jos A van Strijp, Victor J Torres, J Ross Fitzgerald
Bacterial superantigens (SAgs) cause Vβ-dependent T-cell proliferation leading to immune dysregulation associated with the pathogenesis of life-threatening infections such as toxic shock syndrome, and necrotizing pneumonia. Previously, we demonstrated that staphylococcal enterotoxin-like toxin X (SElX) from Staphylococcus aureus is a classical superantigen that exhibits T-cell activation in a Vβ-specific manner, and contributes to the pathogenesis of necrotizing pneumonia. Here, we discovered that SElX can also bind to neutrophils from human and other mammalian species and disrupt IgG-mediated phagocytosis...
September 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28880913/staphylococcal-enterotoxin-like-x-selx-is-a-unique-superantigen-with-functional-features-of-two-major-families-of-staphylococcal-virulence-factors
#15
Ries J Langley, Yi Tian Ting, Fiona Clow, Paul G Young, Fiona J Radcliff, Jeong Min Choi, Richard P Sequeira, Silva Holtfreter, Heather Baker, John D Fraser
Staphylococcus aureus is an opportunistic pathogen that produces many virulence factors. Two major families of which are the staphylococcal superantigens (SAgs) and the Staphylococcal Superantigen-Like (SSL) exoproteins. The former are immunomodulatory toxins that induce a Vβ-specific activation of T cells, while the latter are immune evasion molecules that interfere with a wide range of innate immune defences. The superantigenic properties of Staphylococcal enterotoxin-like X (SElX) have recently been established...
September 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28858870/the-tlr2-antagonist-staphylococcal-superantigen-like-protein-3-acts-as-a-virulence-factor-to-promote-bacterial-pathogenicity-in-vivo
#16
Kirsten J Koymans, Oliver Goldmann, Christofer A Q Karlsson, Wiedjai Sital, Robert Thänert, Adinda Bisschop, Manouk Vrieling, Johan Malmström, Kok P M van Kessel, Carla J C de Haas, Jos A G van Strijp, Eva Medina
Toll-like receptor (TLR) signaling is important in the initiation of immune responses and subsequent instigation of adaptive immunity. TLR2 recognizes bacterial lipoproteins and plays a central role in the host defense against bacterial infections, including those caused by Staphylococcus aureus. Many studies have demonstrated the importance of TLR2 in murine S. aureus infection. S. aureus evades TLR2 activation by secreting two proteins, staphylococcal superantigen-like protein 3 (SSL3) and 4 (SSL4). In this study, we demonstrate that antibodies against SSL3 and SSL4 are found in healthy individuals, indicating that humans are exposed to these proteins during S...
September 1, 2017: Journal of Innate Immunity
https://www.readbyqxmd.com/read/28838616/molecular-analysis-of-immunoglobulin-variable-genes-supports-a-germinal-center-experienced-normal-counterpart-in-primary-cutaneous-diffuse-large-b-cell-lymphoma-leg-type
#17
Anne Pham-Ledard, Martina Prochazkova-Carlotti, Mélanie Deveza, Marie-Pierre Laforet, Marie Beylot-Barry, Béatrice Vergier, Marie Parrens, Jean Feuillard, Jean-Philippe Merlio, Nathalie Gachard
BACKGROUND: Immunophenotype of primary cutaneous diffuse large B-cell lymphoma, leg-type (PCLBCL-LT) suggests a germinal center-experienced B lymphocyte (BCL2+ MUM1+ BCL6+/-). OBJECTIVES: As maturation history of B-cell is "imprinted" during B-cell development on the immunoglobulin gene sequence, we studied the structure and sequence of the variable part of the genes (IGHV, IGLV, IGKV), immunoglobulin surface expression and features of class switching in order to determine the PCLBCL-LT cell of origin...
July 26, 2017: Journal of Dermatological Science
https://www.readbyqxmd.com/read/28807764/staphylococcal-enterotoxin-c2-mutant-drives-t-lymphocyte-activation-through-pi3k-mtor-and-nf-%C3%A4-b-signaling-pathways
#18
Xuanhe Fu, Mingkai Xu, Songyuan Yao, Huiwen Zhang, Chenggang Zhang, Jinghai Zhang
Staphylococcal enterotoxin C2 (SEC2), a superantigen, causes rapid clonal expansion of lymphocytes and secretion of T cell growth factors, leading to a severe inflammatory response within tissues. Although previous studies have shown that ST-4, a SEC2 mutant with enhanced recognition of Vβ regions of T-cell receptors (TCRVβ), can activate an increased number of T cells and produce more cytokines than SEC2. However, the signaling mechanisms of SEC2/ST-4-mediated immune activation have not been addressed. In this study, we showed that the phosphatidylinositide-3-kinase (PI-3K) inhibitor LY294002, mammalian target of rapamycin (mTOR) inhibitor rapamycin, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inhibitor Bay11-7085 could suppress SEC2/ST-4-induced proliferation, CD69/CD25 expression, cell-cycle progression, and IL-2 production in BALB/c mouse splenocytes...
October 15, 2017: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/28794279/nasopharyngeal-infection-by-streptococcus-pyogenes-requires-superantigen-responsive-v%C3%AE-specific-t-cells
#19
Joseph J Zeppa, Katherine J Kasper, Ivor Mohorovic, Delfina M Mazzuca, S M Mansour Haeryfar, John K McCormick
The globally prominent pathogen Streptococcus pyogenes secretes potent immunomodulatory proteins known as superantigens (SAgs), which engage lateral surfaces of major histocompatibility class II molecules and T-cell receptor (TCR) β-chain variable domains (Vβs). These interactions result in the activation of numerous Vβ-specific T cells, which is the defining activity of a SAg. Although streptococcal SAgs are known virulence factors in scarlet fever and toxic shock syndrome, mechanisms by how SAgs contribute to the life cycle of S...
August 9, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28742082/bacterial-deception-of-mait-cells-in-a-cloud-of-superantigen-and-cytokines
#20
REVIEW
Johan K Sandberg, Anna Norrby-Teglund, Edwin Leeansyah
The bacterium Staphylococcus aureus is an important cause of the life-threatening condition toxic shock syndrome in humans. Bacterial toxins known as superantigens (SAgs) generate this illness by acting as broad activators of a substantial fraction of all T lymphocytes, bypassing the normally highly stringent T-cell receptor antigen specificity to cause a systemic inflammatory cytokine storm in the host. In a new study, Shaler et al. found that immune cells called mucosa-associated invariant T (MAIT) cells make an unexpectedly large contribution to the SAg response in a largely T-cell receptor-independent, cytokine-driven manner...
July 2017: PLoS Biology
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