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https://www.readbyqxmd.com/read/29388112/use-of-streptolysin-o-induced-membrane-damage-as-a-method-of-studying-the-function-of-lipid-rafts-during-b-cell-activation
#1
Heather Miller, Wenxia Song
B-lymphocytes have the ability to repair their plasma membranes following injury, such as by bacterial cholesterol-dependent cytolysins. The repair process includes the removal of the pore from the inflicted region of the plasma membrane via lipid raft-mediated internalization. Lipid rafts are critical for B cell receptor (BCR) activation. Cholesterol-dependent pore forming bacterial toxins provide a useful tool for examining the role of lipid rafts in B cell activation and the underlying cellular mechanisms...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29378883/the-endopeptidase-pepo-regulates-the-speb-cysteine-protease-and-is-essential-for-the-virulence-of-invasive-m1t1-streptococcus-pyogenes
#2
Stephan Brouwer, Amanda J Cork, Cheryl-Lynn Y Ong, Timothy C Barnett, Nicholas P West, Kevin S McIver, Mark J Walker
Streptococcus pyogenes (Group A Streptococcus, GAS) causes a wide range of human infections. The pathogenesis of GAS infections is dependent on the temporal expression of numerous secreted and surface-associated virulence factors that interact with host proteins. Streptococcal pyrogenic exotoxin B (SpeB) is one of the most extensively studied toxins produced by GAS, and the coordinate growth phase-dependent regulation of speB expression is linked to disease severity phenotypes. Here we identified the endopeptidase PepO as a novel growth phase-dependent regulator of SpeB in the invasive GAS M1-serotype strain 5448...
January 29, 2018: Journal of Bacteriology
https://www.readbyqxmd.com/read/29366615/the-evaluation-and-management-of-toxic-shock-syndrome-in-the-emergency-department-a-review-of-the-literature
#3
Michael Gottlieb, Brit Long, Alex Koyfman
BACKGROUND: Toxic shock syndrome (TSS) is a severe, toxin-mediated illness that can mimic several other diseases and is lethal if not recognized and treated appropriately. OBJECTIVE: This review provides an emergency medicine evidence-based summary of the current evaluation and treatment of TSS. DISCUSSION: The most common etiologic agents are Staphylococcus aureus and Streptococcus pyogenes. Sources of TSS include postsurgical wounds, postpartum, postabortion, burns, soft tissue injuries, pharyngitis, and focal infections...
January 20, 2018: Journal of Emergency Medicine
https://www.readbyqxmd.com/read/29342444/scarlet-fever-epidemic-in-china-caused-by-streptococcus-pyogenes-serotype-m12-epidemiologic-and-molecular-analysis
#4
Yuanhai You, Mark R Davies, Melinda Protani, Liam McIntyre, Mark J Walker, Jianzhong Zhang
From 2011, Hong Kong and mainland China have witnessed a sharp increase in reported cases, with subsequent reports of epidemic scarlet fever in North Asia and the United Kingdom. Here we examine epidemiological data and investigate the genomic context of the predominantly serotype M12 Streptococcus pyogenes scarlet fever isolates from mainland China. Incident case data was obtained from the Chinese Nationwide Notifiable Infectious Diseases Reporting Information System. The relative risk of scarlet fever in recent outbreak years 2011-2016 was calculated using the median age-standardised incidence rate, compared to years 2003-2010 prior this outbreak...
January 11, 2018: EBioMedicine
https://www.readbyqxmd.com/read/29290232/antibiotic-treatment-of-skin-and-soft-tissue-infections
#5
Y Gillet, M Lorrot, R Cohena, I Hau, E Grimprel, C Gras-Le Guen
Bacterial skin and soft tissues infections are common in children and frequently do not require systemic antibiotics, especially if lesions are superficial. Careful washing is always indicated in superficial lesions and is often sufficient. Careful evaluation of symptoms (which may be difficult despite the accessibility of the lesions) should be performed before prescription. Therefore, the need for drainage (spontaneous or surgical) should be assessed considering that antibiotics are mostly useless if purulent lesions are drained...
December 2017: Archives de Pédiatrie: Organe Officiel de la Sociéte Française de Pédiatrie
https://www.readbyqxmd.com/read/29277539/skin-wound-healing-is-accelerated-by-a-lipid-mixture-representing-major-lipid-components-of-chamaecyparis-obtusa-plant-extract
#6
Byung Eui Kim, Elena Goleva, Clifton F Hall, Sang Hyun Park, Un Ha Lee, Anne M Brauweiler, Joanne E Streib, Brittany N Richers, Gwuicheol Kim, Donald Y M Leung
In chronic non-healing wounds, the healing process is disrupted and wounds are often infected with bacteria. About 85% of lower extremity amputations in diabetes are attributed to deep infection of foot ulcers. Therefore, infection control is critical for wound care. In this study, we analyzed lipid composition of Chamaecyparis (C) obtusa extract, and describe the wound healing properties of its combination of ten major lipid components. A 10 lipid mixture upregulated HBD-3 and LL-37 through the olfactory receptor 2AT4, and induced phosphorylation of extracellular signal-regulated kinases and p38 mitogen-activated protein kinases in primary human keratinocytes...
December 22, 2017: Journal of Investigative Dermatology
https://www.readbyqxmd.com/read/29142545/rapid-screening-of-pyogenic-staphylococcus-aureus-for-confirmation-of-genus-and-species-methicillin-resistance-and-virulence-factors-by-using-two-novel-multiplex-pcr
#7
Abdul Haque, Asma Haque, Muhammad Saeed, Aysha Azhar, Samreen Rasool, Sidra Shan, Beenish Ehsan, Zohaib Nisar
Objectives: Emergence of methicillin resistant Staphylococcus aureus (MRSA) is a major medical problem of current era. These bacteria are resistant to most drugs and rapid diagnosis can provide a clear guideline to clinicians. They possess specific virulence factors and relevant information can be very useful. We designed this study to develop multiplex PCRs to provide rapid information. Methods: We studied 60 Staphylococcus aureus isolates and detected methicillin resistance by cefoxitin sensitivity and targeting of mecA gene...
September 2017: Pakistan Journal of Medical Sciences Quarterly
https://www.readbyqxmd.com/read/28882851/managing-scarlet-fever
#8
(no author information available yet)
Scarlet fever, an infection caused by toxin-producing strains of Streptococcus pyogenes, was associated with high levels of morbidity and mortality when epidemics were common in the 18(th) and 19(th) centuries throughout Europe and the USA.(1) Although this disease nearly disappeared during the 20(th) century, several countries, including the UK, have recently experienced a re-emergence of scarlet fever.(1-3) However, the reason for these new outbreaks remains unclear.(1,4) Despite a general move to reduce the use of antibiotics for many mild self-limiting infections (e...
September 2017: Drug and Therapeutics Bulletin
https://www.readbyqxmd.com/read/28757872/production-characterization-and-antimicrobial-activity-of-mycocin-produced-by-debaryomyces-hansenii-dsmz70238
#9
Safaa A S Al-Qaysi, Halah Al-Haideri, Zaid Akram Thabit, Wijdan Hameed Abd Al-Razzaq Al-Kubaisy, Jamal Abd Al-Rahman Ibrahim
The present study was conducted to estimate the antimicrobial activity and the potential biological control of the killer toxin produced by D. hansenii DSMZ70238 against several pathogenic microorganisms. In this study, the effects of NaCl, pH, and temperature, killer toxin production, and antimicrobial activity were studied. The results showed that the optimum inhibitory effect of killer toxin was at 8% NaCl, and the diameters of clear zones were 20, 22, 22, 21, 14, and 13 mm for Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes, Candida albicans, and Candida neoformans, respectively...
2017: International Journal of Microbiology
https://www.readbyqxmd.com/read/28483238/inverse-relationship-between-toxic-shock-syndrome-toxin-1-antibodies-and-interferon-%C3%AE-and-interleukin-6-in-peripheral-blood-mononuclear-cells-from-patients-with-pediatric-tonsillitis-caused-by-staphylococcus-aureus
#10
Yinshuang Chen, Yanmei Huang, Bingshao Liang, Hui Dong, Shuwen Yao, Yongqiang Xie, Yan Long, Huamin Zhong, Yiyu Yang, Bing Zhu, Sitang Gong, Zhenwen Zhou
INTRODUCTION: Pediatric tonsillitis is frequently caused by Staphylococcus aureus, which is the most common pathogen that causes serious pyogenic infections in humans and endangers human health. S. aureus produces numerous potent virulence factors that play a critical role in the pathogenesis of the infection caused by this bacterium, and one of the most important toxins produced by S. aureus is toxic shock syndrome toxin-1 (TSST-1). The aim of this study is to investigate the first time the levels of IFN-γ and interleukin IL-6 in TSST-1-stimulated PBMCs from pediatric tonsillitis patients and the correlation of these cytokine levels with TSST-1-specific IgG in serum...
June 2017: International Journal of Pediatric Otorhinolaryngology
https://www.readbyqxmd.com/read/28351920/spxa1-and-spxa2-act-coordinately-to-fine-tune-stress-responses-and-virulence-in-streptococcus-pyogenes
#11
Gary C Port, Zachary T Cusumano, Paul R Tumminello, Michael G Caparon
SpxA is a unique transcriptional regulator highly conserved among members of the phylum Firmicutes that binds RNA polymerase and can act as an antiactivator. Why some Firmicutes members have two highly similar SpxA paralogs is not understood. Here, we show that the SpxA paralogs of the pathogen Streptococcus pyogenes, SpxA1 and SpxA2, act coordinately to regulate virulence by fine-tuning toxin expression and stress resistance. Construction and analysis of mutants revealed that SpxA1(-) mutants were defective for growth under aerobic conditions, while SpxA2(-) mutants had severely attenuated responses to multiple stresses, including thermal and oxidative stresses...
March 28, 2017: MBio
https://www.readbyqxmd.com/read/28034602/contribution-of-secreted-nadase-and-streptolysin-o-to-the-pathogenesis-of-epidemic-serotype-m1-streptococcus-pyogenes-infections
#12
Luchang Zhu, Randall J Olsen, Jessica D Lee, Adeline R Porter, Frank R DeLeo, James M Musser
Streptococcus pyogenes secretes many toxins that facilitate human colonization, invasion, and dissemination. NADase (SPN) and streptolysin O (SLO) are two toxins that play important roles in pathogenesis. We previously showed that increased production of SPN and SLO in epidemic serotype M1 and M89 S. pyogenes strains is associated with rapid intercontinental spread and enhanced virulence. The biological functions of SPN and SLO have been extensively studied using eukaryotic cell lines, but the relative contribution of each of these two toxins to pathogenesis of epidemic M1 or M89 strains remains unexplored...
March 2017: American Journal of Pathology
https://www.readbyqxmd.com/read/27991848/molecular-characteristics-of-erythromycin-resistant-streptococcus-pyogenes-strains-isolated-from-children-patients-in-tunis-tunisia
#13
Sonia Ksia, Hanen Smaoui, Manel Hraoui, Aida Bouafsoun, Ihem Boutiba-Ben Boubaker, Amel Kechrid
AIM: The aims of our study were to characterize phenotypically and genotypically erythromycin-resistant Streptococcus pyogenes or group A streptococci (ERGAS) isolates, to evaluate macrolide resistance and to analyze the association between emm types and virulence factors. Included in this study were all ERGAS strains isolated from 2000 to 2013 at the Children's hospital of Tunis. Antimicrobial susceptibility was performed according to the CA-SFM guidelines. Macrolide resistance genes were revealed by polymerase chain reaction (PCR) method...
July 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/27726792/selected-topics-in-anaerobic-bacteriology
#14
REVIEW
Deirdre L Church
Alteration in the host microbiome at skin and mucosal surfaces plays a role in the function of the immune system, and may predispose immunocompromised patients to infection. Because obligate anaerobes are the predominant type of bacteria present in humans at skin and mucosal surfaces, immunocompromised patients are at increased risk for serious invasive infection due to anaerobes. Laboratory approaches to the diagnosis of anaerobe infections that occur due to pyogenic, polymicrobial, or toxin-producing organisms are described...
August 2016: Microbiology Spectrum
https://www.readbyqxmd.com/read/27622163/spondylodiscitis-and-bacteremia-due-to-staphylococcus-hyicus-in-an-immunocompetent-man
#15
Maud Foissac, Maria Lekaditi, Bouchra Loutfi, Agnès Ehrhart, Frédéric-Antoine Dauchy
INTRODUCTION: Staphylococcus hyicus is a coagulase-variable Staphylococcus spp. well-known by veterinarians since it is the major agent of a severe cutaneous infection in piglets called exudative epidermitis. In other species the symptoms of infection are quite different. Human cases are uncommon but seem to occur more frequently after repeated contacts with farm animals. CASE REPORT: We report the case of a 58-year-old man suffering from debilitating subacute lumbar pain, in whom diagnosis of infectious spondylodiscitis was based on spine MRI and positive microbiological results...
September 2016: Germs
https://www.readbyqxmd.com/read/27571972/activation-of-band-3-mediates-group-a-streptococcus-streptolysin-s-based-beta-haemolysis
#16
Dustin L Higashi, Nicolas Biais, Deborah L Donahue, Jeffrey A Mayfield, Charles R Tessier, Kevin Rodriguez, Brandon L Ashfeld, Jeffrey Luchetti, Victoria A Ploplis, Francis J Castellino, Shaun W Lee
Streptococcus pyogenes, or group A Streptococcus (GAS), is a human bacterial pathogen that can manifest as a range of diseases from pharyngitis and impetigo to severe outcomes such as necrotizing fasciitis and toxic shock syndrome. GAS disease remains a global health burden with cases estimated at over 700 million annually and over half a million deaths due to severe infections(1). For over 100 years, a clinical hallmark of diagnosis has been the appearance of complete (beta) haemolysis when grown in the presence of blood...
January 18, 2016: Nature Microbiology
https://www.readbyqxmd.com/read/27507970/regulatory-rnas-in-the-less-studied-streptococcal-species-from-nomenclature-to-identification
#17
REVIEW
Mohamed A Zorgani, Roland Quentin, Marie-Frédérique Lartigue
Streptococcal species are Gram-positive bacteria involved in severe and invasive diseases in humans and animals. Although, this group includes different pathogenic species involved in life-threatening infections for humans, it also includes beneficial species, such as Streptococcus thermophilus, which is used in yogurt production. In bacteria virulence factors are controlled by various regulatory networks including regulatory RNAs. For clearness and to develop logical thinking, we start this review with a revision of regulatory RNAs nomenclature...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27211243/tethered-bilayer-membranes-as-a-complementary-tool-for-functional-and-structural-studies-the-pyolysin-case
#18
Giulio Preta, Marija Jankunec, Frank Heinrich, Sholeem Griffin, Iain Martin Sheldon, Gintaras Valincius
We demonstrate the use of tethered bilayer lipid membranes (tBLMs) as an experimental platform for functional and structural studies of membrane associated proteins by electrochemical techniques. The reconstitution of the cholesterol-dependent cytolysin (CDC) pyolysin (PLO) from Trueperella pyogenes into tBLMs was followed in real-time by electrochemical impedance spectroscopy (EIS). Changes of the EIS parameters of the tBLMs upon exposure to PLO solutions were consistent with the dielectric barrier damage occurring through the formation of water-filled pores in membranes...
September 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27141081/intergenic-variable-number-tandem-repeat-polymorphism-upstream-of-roca-alters-toxin-production-and-enhances-virulence-in-streptococcus-pyogenes
#19
Luchang Zhu, Randall J Olsen, Nicola Horstmann, Samuel A Shelburne, Jia Fan, Ye Hu, James M Musser
Variable-number tandem-repeat (VNTR) polymorphisms are ubiquitous in bacteria. However, only a small fraction of them has been functionally studied. Here, we report an intergenic VNTR polymorphism that confers an altered level of toxin production and increased virulence in Streptococcus pyogenes The nature of the polymorphism is a one-unit deletion in a three-tandem-repeat locus upstream of the rocA gene encoding a sensor kinase. S. pyogenes strains with this type of polymorphism cause human infection and produce significantly larger amounts of the secreted cytotoxins S...
July 2016: Infection and Immunity
https://www.readbyqxmd.com/read/27060235/an-experimental-platform-using-human-intestinal-epithelial-cell-lines-to-differentiate-between-hazardous-and-non-hazardous-proteins
#20
COMPARATIVE STUDY
Bryan P Hurley, Waheed Pirzai, Alex D Eaton, Marc Harper, Jason Roper, Cindi Zimmermann, Gregory S Ladics, Raymond J Layton, Bryan Delaney
Human intestinal epithelial cell lines (T84, Caco-2, and HCT-8) grown on permeable Transwell™ filters serve as models of the gastrointestinal barrier. In this study, this in vitro model system was evaluated for effectiveness at distinguishing between hazardous and non-hazardous proteins. Indicators of cytotoxicity (LDH release, MTT conversion), monolayer barrier integrity ([(3)H]-inulin flux, horseradish peroxidase flux, trans-epithelial electrical resistance [TEER]), and inflammation (IL-8, IL-6 release) were monitored following exposure to hazardous or non-hazardous proteins...
June 2016: Food and Chemical Toxicology
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