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https://www.readbyqxmd.com/read/28512627/laboratory-mice-are-frequently-colonized-with-staphylococcus-aureus-and-mount-a-systemic-immune-response-note-of-caution-for-in-vivo-infection-experiments
#1
Daniel Schulz, Dorothee Grumann, Patricia Trübe, Kathleen Pritchett-Corning, Sarah Johnson, Kevin Reppschläger, Janine Gumz, Nandakumar Sundaramoorthy, Stephan Michalik, Sabine Berg, Jens van den Brandt, Richard Fister, Stefan Monecke, Benedict Uy, Frank Schmidt, Barbara M Bröker, Siouxsie Wiles, Silva Holtfreter
Whether mice are an appropriate model for S. aureus infection and vaccination studies is a matter of debate, because they are not considered as natural hosts of S. aureus. We previously identified a mouse-adapted S. aureus strain, which caused infections in laboratory mice. This raised the question whether laboratory mice are commonly colonized with S. aureus and whether this might impact on infection experiments. Publicly available health reports from commercial vendors revealed that S. aureus colonization is rather frequent, with rates as high as 21% among specific-pathogen-free mice...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28497030/fda-approved-immunosuppressants-targeting-staphylococcal-superantigens-mechanisms-and-insights
#2
REVIEW
Teresa Krakauer
Immunostimulating staphylococcal enterotoxin B (SEB) and related superantigenic toxins cause diseases in human beings and laboratory animals by hyperactivating cells of the immune system. These protein toxins bind to the major histocompatibility complex class II (MHC II) molecules and specific Vβ regions of T-cell receptors (TCRs), resulting in the stimulation of both monocytes/macrophages and T lymphocytes. The bridging of TCR with MHC II molecules by superantigens triggers intracellular signaling cascades, resulting in excessive release of proinflammatory mediators and massive polyclonal T-cell proliferation...
2017: ImmunoTargets and Therapy
https://www.readbyqxmd.com/read/28474248/a-potential-role-for-staphylococcal-and-streptococcal-superantigens-in-driving-skewing-of-tcr-v%C3%AE-subsets-in-tonsillar-hyperplasia
#3
Fiona J Radcliff, Fiona Clow, Murali Mahadevan, James Johnston, Thomas Proft, Richard G Douglas, John D Fraser
The TCR Vβ repertoire from patients with recurrent tonsillitis and/or tonsillar hyperplasia was examined to determine whether the TCR Vβ composition is suggestive of local superantigen activity and if so, whether it is associated with the presence of superantigen producing bacteria. Tonsil specimens were cultured aerobically to allow identification and isolation of the bacterial pathogens Staphylococcus aureus and Group A Streptococcus. TCR Vβ subset analysis of tonsil leucocytes was performed by flow cytometry...
May 4, 2017: Medical Microbiology and Immunology
https://www.readbyqxmd.com/read/28470343/pbmc-activation-via-the-erk-and-stat-signaling-pathways-enhances-the-anti-tumor-activity-of-staphylococcal-enterotoxin-a
#4
Xueting Liu, Liping Zeng, Zhongqiu Zhao, Jianxing He, Yang Xie, Lanyan Xiao, Shan Wang, Junyan Zhang, Zehong Zou, Ying He, Ailin Tao, Jianguo Zhang
Staphylococcal enterotoxin A (SEA) is well known as a superantigen and is highly potent in activating T lymphocytes. And it has been used clinically as an immunomodifier in the treatment of a number of tumors for years. However, the mechanism of its action remains largely unclear. In this study, SEA was found to significantly inhibit the proliferation and induce the death of human lung carcinoma A549 cells when co-cultured with human peripheral blood mononuclear cells (PBMCs). SEA could also induce the proliferation of human PBMCs and stimulate human PBMCs to release a wide range of cytokines that have broad anti-tumor activities such as IFN-γ, TNF-α, IL-2...
May 3, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28469769/toxic-effects-of-seu-are-different-from-those-of-other-staphylococcal-enterotoxins
#5
Yi Li, Hui Deng, Pei-Dian Shi, Dan-Dan Xu, Li-Lin Zhang, Lei Zhang, Jin-Hai Huang
BACKGROUND/PURPOSE: Staphylococcal enterotoxins (SEs) are soluble extracellular proteins excreted by Staphylococcal bacterial strains, sharing similar structures and virulence. More than 20 genotypes of SEs have been identified, but the toxicity of some new SEs is still unclear. METHODS: In this study, we assessed the toxicity effects of six recombinant SEs (rSEA, rSEO, rSEG, rSEK, rSEU and rSEQ) on Balb/c mice by reverse transcription-polymerase chain reaction (RT-PCR)-based methods and enzyme activity detection...
2017: American Journal of Translational Research
https://www.readbyqxmd.com/read/28468970/concomitant-disruption-of-cd4-and-cd8-genes-facilitates-the-development-of-double-negative-%C3%AE-%C3%AE-tcr-peripheral-t-cells-that-respond-robustly-to-staphylococcal-superantigen
#6
Vaidehi R Chowdhary, Ashton Krogman, Ashenafi Y Tilahun, Mariam P Alexander, Chella S David, Govindarajan Rajagopalan
Mature peripheral double negative T (DNT) cells expressing αβ TCR but lacking CD4/CD8 coreceptors play protective as well as pathogenic roles. To better understand their development and functioning in vivo, we concomitantly inactivated CD4 and CD8 genes in mice with intact MHC class I and class II molecules with the hypothesis that this would enable the development of DNT cells. We also envisaged that these DNT cells could be activated by bacterial superantigens in vivo as activation of T cells by superantigens does not require CD4 and CD8 coreceptors...
May 3, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28459299/enhanced-nasopharyngeal-infection-and-shedding-associated-with-an-epidemic-lineage-of-emm3-group-a-streptococcus
#7
Baharak Afshar, Claire E Turner, Theresa Lamagni, Ken Smith, Ali Al-Shahib, Anthony Underwood, Matthew T G Holden, Androulla Efstratiou, Shiranee Sriskandan
Background A group A Streptococcus (GAS) lineage of genotype emm3, sequence type 15 (ST15) was associated with a six month upsurge in invasive GAS disease in the UK. The epidemic lineage (Lineage C) had lost two typical emm3 prophages, Φ315.1 and Φ315.2 associated with the superantigen ssa, but gained a different prophage (ΦUK-M3.1) associated with a different superantigen, speC and a DNAse spd1. Methods and Results The presence of speC and spd1 in Lineage C ST15 strains enhanced both in vitro mitogenic and DNAse activities over non-Lineage C ST15 strains...
May 1, 2017: Virulence
https://www.readbyqxmd.com/read/28442219/virulence-potential-of-staphylococcus-aureus-isolates-from-buruli-ulcer-patients
#8
Nana Ama Amissah, Monika A Chlebowicz, Anthony Ablordey, Caitlin S Tetteh, Isaac Prah, Tjip S van der Werf, Alex W Friedrich, Jan Maarten van Dijl, Ymkje Stienstra, John W Rossen
Buruli ulcer (BU) is a necrotizing infection of the skin and subcutaneous tissue caused by Mycobacterium ulcerans. BU wounds may also be colonized with other microorganisms including Staphylococcus aureus. This study aimed to characterize the virulence factors of S. aureus isolated from BU patients. Previously sequenced genomes of 21 S. aureus isolates from BU patients were screened for the presence of virulence genes. The results show that all S. aureus isolates harbored on their core genomes genes for known virulence factors like α-hemolysin, and the α- and β-phenol soluble modulins...
April 19, 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/28434738/relationships-among-superantigen-toxin-gene-profiles-genotypes-and-pathogenic-characteristics-of-staphylococcus-aureus-isolates-from-bovine-mastitis
#9
Dong Wang, Limei Zhang, Changfu Yong, Mingliang Shen, Tariq Ali, Muhammad Shahid, Kun Han, Xuezhang Zhou, Bo Han
Staphylococcus aureus is one of the major etiological agents of bovine mastitis, harboring a wide variety of staphylococcal superantigen (SAg) toxin genes. The SAg toxin genes are reported to be closely associated with the pathogenicity of the Staph. aureus causing the bovine mastitis. This study was conducted to investigate SAg toxin gene profiles and to assess the relationships among SAg toxin genes, genotypes of Staph. aureus, and their pathogenic properties. A total of 327 quarter milk samples were collected from bovine mastitis cases for isolation and identification of pathogens...
April 20, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28428772/molecular-characterization-of-staphylococcus-aureus-isolated-from-bovine-mastitis-and-close-human-contacts-in-south-african-dairy-herds-genetic-diversity-and-inter-species-host-transmission
#10
Tracy Schmidt, Marleen M Kock, Marthie M Ehlers
Staphylococcus aureus is one of the most common etiological agents of contagious bovine mastitis worldwide. The purpose of this study was to genetically characterize a collection of S. aureus isolates (bovine = 146, human = 12) recovered from cases of bovine mastitis and nasal swabs of close human contacts in the dairy environment. Isolates were screened for a combination of clinically significant antimicrobial and virulence gene markers whilst the molecular epidemiology of these isolates and possible inter-species host transmission was investigated using a combination of genotyping techniques...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28401320/the-virulence-factors-of-group-a-streptococcus-strains-isolated-from-invasive-and-non-invasive-infections-in-polish-and-german-centres-2009-2011
#11
M Strus, P B Heczko, E Golińska, A Tomusiak, A Chmielarczyk, M Dorycka, M van der Linden, A Samet, A Piórkowska
Streptococcus pyogenes (GAS) is one of the major human pathogenic bacteria that cause a wide range of diseases. Currently, increased incidence of streptococcal invasive infections is observed worldwide. In this study, we focused on the prevalence of genes encoding superantigens and type M proteins in the population of GAS strains from invasive versus non-invasive infections. We tested 253 GAS strains: 48 strains from patients with invasive infections (18 from wound/deep skin localization, 30 from women in labour) and 205 strains from non-invasive forms (147 from common infections of the upper respiratory, 49 from the vagina of females with genital tract infections and 9 from non-invasive wound and superficial skin infections)...
April 11, 2017: European Journal of Clinical Microbiology & Infectious Diseases
https://www.readbyqxmd.com/read/28375567/biological-characteristics-of-staphylococcal-enterotoxin-q-and-its-potential-risk-for-food-poisoning
#12
D-L Hu, H K Ono, S Isayama, R Okada, M Okamura, L C Lei, Z S Liu, X-C Zhang, M Y Liu, J C Cui, A Nakane
AIMS: To elucidate the biological characteristics and stability of a newly identified staphylococcal enterotoxin Q (SEQ) against heating and digestive enzymes, and evaluate the risk of seq-harboring S. aureus in food poisoning. METHODS AND RESULTS: Purified SEQ was treated with heating, pepsin and trypsin that are related to food cooking, stomach and intestine conditions. Superantigenic activity of SEQ was assessed by determining the ability of IL-2 induction in mouse spleen cells...
April 4, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28362113/staphylococcal-enterotoxins-and-enterotoxin-like-toxins-with-special-reference-to-dairy-products-an-overview
#13
Noreddine Benkerroum
Staphylococcal enterotoxins (SEs) have been raising health concerns for food safety due to their association with Staphylococcal Food Poisoning (SFP). As superantigens, they also cause the life threatening Toxic Shock Syndrome (TSS), the transmission of which via food cannot be ruled out despite the lack of epidemiological evidence. To date, at least 23 of these exotoxins are known and separated into SEs and staphylococcal enterotoxin-like (SEl) depending on whether or not they invoke emesis. This work presents an up-to-date overview on the presently known SEs/SEls from the perspective of their classification, pathogenesis, and genetic organisation...
March 31, 2017: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/28359755/a-novel-staphylococcal-enterotoxin-b-subunit-vaccine-candidate-elicits-protective-immune-response-in-a-mouse-model
#14
Jun Young Choi, Sungho Shin, Na Young Kim, Woo Sung Son, Tae Jin Kang, Dong Hyun Song, Chi Ho Yu, Gyeung Haeng Hur, Seong Tae Jeong, Young Kee Shin
Staphylococcal enterotoxin B (SEB), produced by the gram-positive bacterium Staphylococcus aureus, is responsible for food poisoning and toxic shock syndrome, and is considered a potential bioterrorism agent. Unfortunately, still now no approved vaccines are available against SEB. In this study, we constructed a series of nontoxic SEB mutants (mSEBs) and examined whether these mSEBs provide protective immunity against SEB challenge. These mSEB vaccine candidates did not demonstrate superantigen activity in mouse splenocyte cultures...
March 27, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28320831/interference-of-the-t-cell-and-antigen-presenting-cell-costimulatory-pathway-using-ctla4-ig-abatacept-prevents-staphylococcal-enterotoxin-b-pathology
#15
Sarah J C Whitfield, Chris Taylor, Jane E Risdall, Gareth D Griffiths, James T A Jones, E Diane Williamson, Sjoerd Rijpkema, Luisa Saraiva, Sandrine Vessillier, A Christopher Green, Alun J Carter
Staphylococcal enterotoxin B (SEB) is a bacterial superantigen that binds the receptors in the APC/T cell synapse and causes increased proliferation of T cells and a cytokine storm syndrome in vivo. Exposure to the toxin can be lethal and cause significant pathology in humans. The lack of effective therapies for SEB exposure remains an area of concern, particularly in scenarios of acute mass casualties. We hypothesized that blockade of the T cell costimulatory signal by the CTLA4-Ig synthetic protein (abatacept) could prevent SEB-dependent pathology...
May 15, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28286804/bacterial-superantigen-toxins-induce-a-lethal-cytokine-storm-by-enhancing-b7-2-cd28-costimulatory-receptor-engagement-a-critical-immune-checkpoint
#16
Raymond Kaempfer, Andrey Popugailo, Revital Levy, Gila Arad, Dalia Hillman, Ziv Rotfogel
Formation of the costimulatory axis between the B7-2 and CD28 coreceptors is critical for T-cell activation. Superantigens, Gram-positive bacterial virulence factors, cause toxic shock and sepsis by hyperinducing inflammatory cytokines. We report a novel role for costimulatory receptors CD28 and B7-2 as obligatory receptors for superantigens, rendering them therapeutic targets. We show that by engaging not only CD28 but also its coligand B7-2 directly, superantigens potently enhance the interaction between B7-2 and CD28, inducing thereby T-cell hyperactivation...
2017: Receptors & Clinical Investigation
https://www.readbyqxmd.com/read/28274699/members-of-a-new-subgroup-of-streptococcus-anginosus-harbor-virulence-related-genes-previously-observed-in-streptococcus-pyogenes
#17
Anshu Babbar, Venkatesan Naveen Kumar, René Bergmann, Israel Barrantes, Dietmar H Pieper, Andreas Itzek, D Patric Nitsche-Schmitz
Conventionally categorized as commensals, the Streptococci of the species S. anginosus are facultative human pathogens that are difficult to diagnose and often overlooked. Furthermore, detailed investigation and diagnosis of S. anginosus infections is hampered by unexplored taxonomy and widely elusive molecular pathogenesis. To explore their pathogenic potential, S. anginosus isolates collected from patients of two geographical locations (Vellore, India and Leipzig, Germany) were subjected to multi-locus sequence analysis (MLSA)...
April 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/28260936/microbiome-in-atopic-dermatitis
#18
REVIEW
Uwe Wollina
Atopic dermatitis (AD) is a common chronic inflammatory skin disease affecting ~10-20% of the general population. AD is characterized by disturbances in epidermal barrier function and hyperactive immune response. Recently, changes in the skin and intestinal microbiome have been analyzed in more detail. The available data suggest a link between disturbed skin microbiome and course of the disease. Flares of the disease are associated with an expansion of Staphylococcus aureus on lesional skin and a substantial loss of biodiversity in skin microbiome...
2017: Clinical, Cosmetic and Investigational Dermatology
https://www.readbyqxmd.com/read/28241767/multiple-sclerosis-an-example-of-pathogenic-viral-interaction
#19
REVIEW
Walter Fierz
A hypothesis is formulated on viral interaction between HHV-6A and EBV as a pathogenic mechanism in Multiple Sclerosis (MS). Evidence of molecular and genetic mechanisms suggests a link between HHV-6A infection and EBV activation in the brain of MS patients leading to intrathecal B-cell transformation. Consequent T-cell immune response against the EBV-infected cells is postulated as a pathogenic basis for inflammatory lesion formation in the brain of susceptible individuals. A further link between HHV-6A and EBV involves their induction of expression of the human endogenous retrovirus HERV-K18-encoded superantigen...
February 28, 2017: Virology Journal
https://www.readbyqxmd.com/read/28235987/staphylococcus-enterotoxin-profile-of-china-isolates-and-the-superantigenicity-of-some-novel-enterotoxins
#20
Menglu Shen, Yi Li, Linlin Zhang, Songbao Dai, Jiashun Wang, Yongqing Li, Lei Zhang, Jinhai Huang
The genus of staphylococcus widely distributes in environments and contributes to a variety of animal and human diseases. The enterotoxins (SEs) secreted by this type of pathogen have been the leading cause of bacterial toxic shock syndrome and food poisoning, and thus present a substantial concern to public health. In this study, we analyzed the superantigen profile of 122 staphylococcus strains isolated from diverse sources. When screened for the presence and prevalence of 17 known se or se-like (sel) genes, except selj, all other genes were detected in these isolates...
February 24, 2017: Archives of Microbiology
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