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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
#1
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
#2
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
#3
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
#4
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...
December 19, 2016: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/27726792/selected-topics-in-anaerobic-bacteriology
#5
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
#6
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
#7
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...
2016: Nature Microbiology
https://www.readbyqxmd.com/read/27507970/regulatory-rnas-in-the-less-studied-streptococcal-species-from-nomenclature-to-identification
#8
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
#9
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
#10
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
#11
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
https://www.readbyqxmd.com/read/26938870/nad-glycohydrolase-promotes-intracellular-survival-of-group-a-streptococcus
#12
Onkar Sharma, Maghnus O'Seaghdha, Jorge J Velarde, Michael R Wessels
A global increase in invasive infections due to group A Streptococcus (S. pyogenes or GAS) has been observed since the 1980s, associated with emergence of a clonal group of strains of the M1T1 serotype. Among other virulence attributes, the M1T1 clone secretes NAD+-glycohydrolase (NADase). When GAS binds to epithelial cells in vitro, NADase is translocated into the cytosol in a process mediated by streptolysin O (SLO), and expression of these two toxins is associated with enhanced GAS intracellular survival...
March 2016: PLoS Pathogens
https://www.readbyqxmd.com/read/26928506/-reference-values-of-antistreptolysin-o-and-asymptomatic-carriers-of-%C3%AE-hemolytic-streptococci-in-adolescents-and-adults-at-municipality-francisco-linares-alc%C3%A3-ntara-venezuela
#13
Clara Gutiérrez, María Chacón, Luis Pérez-Ybarra, Hilary Rivero, Sheryl Straga, Juan Luis-León
INTRODUCTION: β-hemolytic streptococci (Streptococcus pyogenes) groups A, C or G, secretes streptolysin O, toxin which causes in the infected individual an adaptive humoral immune response with production of serum antibodies called anti-streptolysin O (ASO). OBJECTIVES: To determine the reference value of ASO in a sample of 159 individuals aged 16-72 years from municipality Francisco Linares Alcántara, Aragua state, applying indirect (passive) agglutination test...
December 2015: Revista Chilena de Infectología: órgano Oficial de la Sociedad Chilena de Infectología
https://www.readbyqxmd.com/read/26838722/the-nadase-negative-variant-of-the-streptococcus-pyogenes-toxin-nad%C3%A2-%C2%BA-glycohydrolase-induces-jnk1-mediated-programmed-cellular-necrosis
#14
Sukantha Chandrasekaran, Michael G Caparon
UNLABELLED: Virulence factors are often multifunctional and contribute to pathogenesis through synergistic mechanisms. For the human pathogen Streptococcus pyogenes, two factors that act synergistically are the S. pyogenes NAD(+) glycohydrolase (SPN) and streptolysin O (SLO). Through distinct mechanisms, SLO forms pores in host cell membranes and translocates SPN into the host cell cytosol. Two natural variants of SPN exist, one that exhibits NADase activity and one that lacks this function, and both versions are translocated and act in concert with SLO to cause an accelerated death response in epithelial cells...
February 2, 2016: MBio
https://www.readbyqxmd.com/read/26813865/spontaneous-regression-of-tumour-and-the-role-of-microbial-infection-possibilities-for-cancer-treatment
#15
REVIEW
Petra Kucerova, Monika Cervinkova
This review deals with the role of microorganisms in spontaneous regression of a tumour. Spontaneous cancer regression is a phenomenon that has been described for many centuries. One of the most well known methods of inducing spontaneous regression of cancer is the application of Coley's toxin (heat-killed Streptococcus pyogenes and Serratia marcescens), which has been used for the successful treatment of sarcomas, carcinomas, lymphomas, myelomas and melanomas. In clinical practice, the use of Bacillus Calmette-Guérin vaccine for the treatment of superficial urinary bladder cancer is the most common instance of the application of microorganisms for the treatment of cancer...
April 2016: Anti-cancer Drugs
https://www.readbyqxmd.com/read/26676040/nasopharyngeal-infection-of-mice-with-streptococcus-pyogenes-and-in-vivo-detection-of-superantigen-activity
#16
Joseph J Zeppa, Adrienne T Wakabayashi, Katherine J Kasper, Stacey X Xu, S M Mansour Haeryfar, John K McCormick
Streptococcus pyogenes is a globally prominent human-specific pathogen that is responsible for an enormous burden of infectious disease. Despite intensive experimental efforts to understand the molecular correlates that contribute to invasive infections, there has been less focus on S. pyogenes carriage and local infection of the nasopharynx. This chapter describes an acute nasopharyngeal infection model in mice that is utilized in our laboratory to study the role of superantigen toxins in the biology of S...
2016: Methods in Molecular Biology
https://www.readbyqxmd.com/read/26602794/highly-virulent-m1-streptococcus-pyogenes-isolates-resistant-to-clindamycin
#17
C Plainvert, C Martin, J Loubinoux, G Touak, N Dmytruk, G Collobert, A Fouet, M-C Ploy, C Poyart
CONTEXT: Emm1-type group A Streptococcus (GAS), or Streptococcus pyogenes, is mostly responsible for invasive infections such as necrotizing fasciitis (NF) and streptococcal toxic shock syndrome (STSS). The recommended treatment of severe invasive GAS infections is a combination of clindamycin and penicillin. Until 2012, almost all emm1 isolates were susceptible to clindamycin. OBJECTIVES: We aimed to identify the phenotypic and genotypic characteristics of emm1 GAS clone resistant to clindamycin...
November 2015: Médecine et Maladies Infectieuses
https://www.readbyqxmd.com/read/26508447/identification-of-the-streptococcus-pyogenes-surface-antigens-recognised-by-pooled-human-immunoglobulin
#18
Mark Reglinski, Magdalena Gierula, Nicola N Lynskey, Robert J Edwards, Shiranee Sriskandan
Immunity to common bacteria requires the generation of antibodies that promote opsonophagocytosis and neutralise toxins. Pooled human immunoglobulin is widely advocated as an adjunctive treatment for clinical Streptococcus pyogenes infection however, the protein targets of the reagent remain ill defined. Affinity purification of the anti-streptococcal antibodies present within pooled immunoglobulin resulted in the generation of an IgG preparation that promoted opsonophagocytic killing of S. pyogenes in vitro and provided passive immunity in vivo...
October 28, 2015: Scientific Reports
https://www.readbyqxmd.com/read/26443457/trading-capsule-for-increased-cytotoxin-production-contribution-to-virulence-of-a-newly-emerged-clade-of-emm89-streptococcus-pyogenes
#19
Luchang Zhu, Randall J Olsen, Waleed Nasser, Ivan de la Riva Morales, James M Musser
UNLABELLED: Strains of emm89 Streptococcus pyogenes have become one of the major causes of invasive infections worldwide in the last 10 years. We recently sequenced the genome of 1,125 emm89 strains and identified three major phylogenetic groups, designated clade 1, clade 2, and the epidemic clade 3. Epidemic clade 3 strains, which now cause the great majority of infections, have two distinct genetic features compared to clade 1 and clade 2 strains. First, all clade 3 organisms have a variant 3 nga promoter region pattern, which is associated with increased production of secreted cytolytic toxins SPN (S...
2015: MBio
https://www.readbyqxmd.com/read/26313273/-carriage-of-streptococcus-pyogenes-in-primary-school-children-m-protein-types-pyrogenic-toxin-genes-and-investigation-of-the-clonal-relationships-between-the-isolates
#20
Barış Otlu, Cemşit Karakurt, Yaşar Bayındır, Üner Kayabaş, Yusuf Yakupoğulları, Harika Gözükara Bağ
M-protein and pyrogenic toxins are the most important virulence factors of Streptococcus pyogenes, and they play significant role in the pathophysiology of acute rheumatoid fever and scarlet fever, respectively. In this study, the pharyngeal carriage of S.pyogenes of the primary school children, clonal relationship of the strains, M-protein types, and the presence of pyrogenic toxin genes were aimed to be investigated. A total of 668 throat cultures obtained from children (age range: 6-16 years) in two primary schools in our region, were included in the study...
July 2015: Mikrobiyoloji Bülteni
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