Staphylococcal Toxic Shock Research Articles

Editorial introductions

Current Opinion in Infectious Diseases was launched in 1988. It is part of a successful series of review journals whose unique format is designed to provide a systematic and critical assessment of the literature as presented in the many primary journals. The field of infectious diseases is divided into 11 sections that are reviewed once a year. Each section is assigned a Section Editor, a leading authority in the area, who identifies the most important topics at that time. Here we are pleased to introduce the Section Editors for this issue. SECTION EDITORS Paul T. HeathPaul T. HeathPaul T. Heath is a Professor and Honorary Consultant in Paediatric Infectious Diseases at St George's, University of London and Vaccine Institute in London, UK. His training in paediatrics and infectious diseases was at the Royal Children's Hospital, Melbourne, Australia, the John Radcliffe Hospital, Oxford, UK and St George's Hospital, London, UK. His particular research interests are in the epidemiology of vaccine preventable diseases, in clinical vaccine trials, particularly in at-risk groups, and in perinatal infections and he has published over 150 original or review papers in these areas. He sits on national committees concerned with neonatal infections, meningitis, group B streptococcus prevention and on immunisation policies in children. He is a Fellow of the Royal Australasian College of Physicians, a Fellow of the Royal College of Paediatrics and Child Health, a member of the research committee of the European Society of Paediatric Infectious Diseases and a member of the Science Board of the international Brighton Collaboration on vaccine safety. Dennis L. StevensDennis L. StevensDr Stevens received his PhD in Microbiology from Montana State University, USA and his MD from the University of Utah College of Medicine, USA. Following a residency in internal medicine at the University of Utah, Dr Stevens completed an infectious disease fellowship at Brooke Army Medical Center in San Antonio, Texas, USA and has been Chief of Infectious Diseases at the Veterans Affairs Medical Center in Boise, Idaho, USA, since 1979. Dr Stevens is Professor of Medicine at the University of Washington School of Medicine, USA and his major clinical interests have been in Staphylococcal and Streptococcal toxic shock syndromes and in skin and soft tissue infections including necrotizing fasciitis and gas gangrene. His research interests are centered around gram positive bacteria and the role of extracellular toxins in the pathogenesis of severe soft tissue infection caused by Streptococcus pyogenes, Clostridium perfringens and methicillin-resistant Staphylococcus aureus. Current research efforts investigate the mechanisms of toxin induced shock and organ dysfunction including cardiomyopathy, the effects of toxins on endothelial cells, granulocytes and platelets and the importance of the mechanisms of action of antibiotics in treating gram positive infections. Dr Stevens has published over 170 original research papers, 89 book chapters, 143 abstracts and three books, Streptococcal Infections: Clinical Aspects, Microbiology and Molecular Pathogenesis (co-authored with Dr. Edward Kaplan), An Atlas of Infectious Diseases: Skin and Soft Tissue, Bone and Joint Infections and Netter's Textbook of Infectious Diseases (co- authored with Dr. Elaine Jong). Dr Stevens is a member of the American Society of Microbiology, a Fellow in the American College of Physicians, a Fellow in the Infectious Disease Society of America and a member of the Association of American Physicians. In 2000, Dr Stevens received the Infectious Disease Society of America's Society Citation Award and in 2001, The William Altemier Award from the Surgical Infectious Disease Society. Dr Stevens has served as a consultant for the CDC Working Group on Invasive Group A streptococcal infections and for the WHO and NIH on similar matters. Dr Stevens is currently Chairman of the Infectious Disease Society of America Guidelines Committee on Skin and Soft Tissue Infections.

Staphylococcal toxic shock syndrome: superantigen-mediated enhancement of endotoxin shock and adaptive immune suppression.

Infectious diseases caused by Staphylococcus aureus present a significant clinical and public health problem. S. aureus causes some of the most severe hospital-associated and community-acquired illnesses. Specifically, it is the leading cause of infective endocarditis and osteomyelitis, and the second leading cause of sepsis in the USA. While pathogenesis of S. aureus infections is at the center of current research, many questions remain about the mechanisms underlying staphylococcal toxic shock syndrome (TSS) and associated adaptive immune suppression. Both conditions are mediated by staphylococcal superantigens (SAgs)-secreted staphylococcal toxins that are major S. aureus virulence factors. Toxic shock syndrome toxin-1 (TSST-1) is the SAg responsible for almost all menstrual TSS cases in the USA. TSST-1, staphylococcal enterotoxin B and C are also responsible for most cases of non-menstrual TSS. While SAgs mediate all of the hallmark features of TSS, such as fever, rash, hypotension, and multi-organ dysfunction, they are also capable of enhancing the toxic effects of endogenous endotoxin. This interaction appears to be critical in mediating the severity of TSS and related mortality. In addition, interaction between SAgs and the host immune system has been recognized to result in a unique form of adaptive immune suppression, contributing to poor outcomes of S. aureus infections. Utilizing rabbit models of S. aureus infective endocarditis, pneumonia and sepsis, and molecular genetics techniques, we aim to elucidate the mechanisms of SAg and endotoxin synergism in the pathogenesis of TSS, and examine the cellular and molecular mechanisms underlying SAg-mediated immune dysfunction.

Quemaduras graves relacionadas con la terapia inhalatoria con vahos

IntroductionDespite lack of proven effectiveness and its potential to cause severe burns, steam inhalation therapy (SIT) is still used as a treatment for benign respiratory conditions. ObjectiveTo characterize cases of burns related to steam inhalation therapy (BRSIT) in order to formulate appropriate preventive criteria. Patients and methodsA review was conducted on cases of BRSIT admitted to a Burns Unit between 2006 and 2012, analysing epidemiological data, clinical aspects, severity and course. ResultsA total of 530 patients were admitted; 375 (70%) with scalds, and 15 with BRSIT (2.8% of burns; 4% of scalds). SIT was indicated in most cases for mild upper airway infections. The median age of patients was 7 years (2.5m-14y). The burned area (BA) was ≥10% in 60% of cases (max. BA 22%). Injuries involved trunk, genital area, and extremities; only in one case was the face affected. The mean hospital length-of-stay was 14 days (3-30d). Five patients (33%) were admitted to the PICU, most of them (60%) younger than 3 years. Eight patients (53%) underwent surgical treatment (skin grafting). In a 12-year-old patient whooping cough was diagnosed in the Burns Unit, and a 2.5-year-old patient developed staphylococcal toxic shock syndrome. No patient died. The final course was satisfactory in all patients. ConclusionsBRSIT can be severe and cause significant use of health resources. Professionals caring for children, particularly paediatricians, should seriously consider their prevention, avoiding treatments with SIT, and educating parents in order not to use it on their own.

English

The aim of this study was to determine the prevalence of nasal carriage of Staphylococcus aureus among patients and personnel of private centers at Casablanca, and to determine the resistance pattern of isolates. The carriage of virulence toxin genes by the methicillin resistant strains was also investigated. This study was conducted from November 2008 to February 2009. Nasal swabs were taken from 145 and 42 patients and personnel respectively. The susceptibility testing to 16 antibiotics was performed using the agar disc diffusion method. Minimum inhibitory concentrations (MICs) of oxacillin were determined by the agar dilution method for all strains demonstrating resistance to cefoxitin. In addition, resistant isolates were examined for the existence of the mecA gene by polymerase chain reaction (PCR). Furthermore, the carriage of 22 virulence toxin genes among strains showing resistance to cefoxitin was investigated by PCR Multiplex. The prevalence of nasal carriage of S. aureus was 32.4% (n=47) and 38.1% (n=16) in patients and personnel, respectively. Patients’ strains showed 16 resistance patterns against only 4 in personnel strains. No S. aureus isolates were found to be resistant to lincomycin, pristinamycin, gentamicin, chloramphenicol, trimethoprim-sulfamethoxazole, rifampicin and vancomycin, while over 90% (n = 59) were resistant to penicillin G. For the other antibiotics, the percentage of resistance varied between 2.63 and 18.75%. One S. aureus (1.6%) was methicillin resistant by possession of mecA gene. This isolate harboured the staphylococcal enterotoxin genes sec, sed, sell, selm, selo, ser and toxic shock syndrome toxin gene (tst). Investigation of S. aureus nasal carriage and characterization of isolates among patients undergoing hemodialysis is important to develop infection prevention and to limit the spread of methicillin resistant S. aureus (MRSA) strains. Key words: Hemodialysis centers, patients, personnel, Staphylococcus aureus, nasal carriage, antibiotic susceptibility, methicillin resistance, toxin genes.

Mesenchymal stromal (stem) cells suppress pro-inflammatory cytokine production but fail to improve survival in experimental staphylococcal toxic shock syndrome

BackgroundToxic shock syndrome (TSS) is caused by an overwhelming host-mediated response to bacterial superantigens produced mainly by Staphylococcus aureus and Streptococcus pyogenes. TSS is characterized by aberrant activation of T cells and excessive release of pro-inflammatory cytokines ultimately resulting in capillary leak, septic shock, multiple organ dysfunction and high mortality rates. No therapeutic or vaccine has been approved by the U.S. Food and Drug Administration for TSS, and novel therapeutic strategies to improve clinical outcome are needed. Mesenchymal stromal (stem) cells (MSCs) are stromal cells capable of self-renewal and differentiation. Moreover, MSCs have immunomodulatory properties, including profound effects on activities of T cells and macrophages in specific contexts. Based on the critical role of host-derived immune mediators in TSS, we hypothesized that MSCs could modulate the host-derived proinflammatory response triggered by Staphylococcal enterotoxin B (SEB) and improve survival in experimental TSS.MethodsEffects of MSCs on proinflammatory cytokines in peripheral blood were measured in wild-type C57BL/6 mice injected with 50 μg of SEB. Effects of MSCs on survival were monitored in fatal experimental TSS induced by consecutive doses of D-galactosamine (10 mg) and SEB (10 μg) in HLA-DR4 transgenic mice.ResultsDespite significantly decreasing serum levels of IL-2, IL-6 and TNF induced by SEB in wild-type mice, human MSCs failed to improve survival in experimental TSS in HLA-DR4 transgenic mice. Similarly, a previously described downstream mediator of human MSCs, TNF-stimulated gene 6 (TSG-6), did not significantly improve survival in experimental TSS. Furthermore, murine MSCs, whether unstimulated or pre-treated with IFNγ, failed to improve survival in experimental TSS.ConclusionsOur results suggest that the immunomodulatory effects of MSCs are insufficient to rescue mice from experimental TSS, and that mediators other than IL-2, IL-6 and TNF are likely to play critical mechanistic roles in the pathogenesis of experimental TSS.

Concurrence of fatal staphylococcal toxic shock syndrome and systemic lupus erythematosus

Staphylococcal toxic shock syndrome (STSS) is an acute, toxin-mediated febrile illness that rapidly leads to multiple organ dysfunction syndromes, and systemic lupus erythematosus (SLE) is a multisystem autoimmune and inflammatory disease. Differential diagnosis in STSS involved a number of common diseases associated with a wide range of nonmenstrual-related conditions, including SLE. Therefore, it is difficult to distinguish from each other initially. We report a case of concurrent fatal STSS and SLE who was treated as sepsis initially, which leads to grave prognosis.

The impact of Staphylococcus aureus-associated molecular patterns on staphylococcal superantigen-induced toxic shock syndrome and pneumonia.

Staphylococcus aureus is capable of causing a spectrum of human illnesses. During serious S. aureus infections, the staphylococcal pathogen-associated molecular patterns (PAMPs) such as peptidoglycan, lipoteichoic acid, and lipoproteins and even intact S. aureus, are believed to act in conjunction with the staphylococcal superantigens (SSAg) to activate the innate and adaptive immune system, respectively, and cause immunopathology. However, recent studies have shown that staphylococcal PAMPs could suppress inflammation by several mechanisms and protect from staphylococcal toxic shock syndrome, a life-threatening systemic disease caused by toxigenic S. aureus. Given the contradictory pro- and anti-inflammatory roles of staphylococcal PAMPs, we examined the effects of S. aureus-derived molecular patterns on immune responses driven by SSAg in vivo using HLA-DR3 and HLA-DQ8 transgenic mice. Our study showed that neither S. aureus-derived peptidoglycans (PGN), lipoteichoic acid (LTA), nor heat-killed Staphylococcus aureus (HKSA) inhibited SSAg-induced T cell proliferation in vitro. They failed to antagonize the immunostimulatory effects of SSAg in vivo as determined by their inability to attenuate systemic cytokine/chemokine response and reduce SSAg-induced T cell expansion. These staphylococcal PAMPs also failed to protect HLA-DR3 as well as HLA-DQ8 transgenic mice from either SSAg-induced toxic shock or pneumonia induced by a SSAg-producing strain of S. aureus.

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Introduction: Streptococcal toxic-shock syndrome (STSS) carries a high mortality of 39%(1,2) and is defined by a criteria of isolation of Group A Streptococcus (GAS) from a sterile site with hypotension as well as clinical or laboratory evidence of two or more of the following: renal impairment, coagulopathy, liver abnormalities, acute respiratory distress syndrome, extensive tissue necrosis or erythematous rash(3). Almost half the sources of infection are not found. The mechanism of action is similar to that of Staphylococcal toxic syndrome via exotoxin (super antigens) triggering the immune similar to that of an allergic reaction leading widespread vessel dilation and shock with multi-organ failure. A 54 year old male with no significant past medical history comes to the emergency room with complaints of sudden fatigue, nausea, vomiting, fever and shortness of breath for the last few hours. In the emergency room, he was noted to be hypotensive despite adequate fluid resuscitation and tachypnic, which ultimately required intubation. His physical exam revealed a temperature over 102°F, requiring mechanical ventilation with 100% FiO2 with an oxygen saturation of 90%, 80/50 mmHg and a heart rate of 120 beats per minute. Skin was warm to touch without any evidence of rash, awake on the ventilator able to follow commands, clear breath sounds, tachycardic without evidence of murmur, soft abdomen with no evidence of guarding or rigidity. No bowel sounds were heard. Radiological pan scan was negative. Notable lab investigations yielded leukopenia, lactic acid of 9mg/dl, coagulopathy, deranged hepatic profile and renal dysfunction. Blood cultures yielded Streptococcus pyogenes; other cultures including lumbar, sputum and urine culture were negative. Empiric antibiotics including a beta-lactam had been started on arrival and the patient continued to deteriorate. When the blood cultures returned clindamycin was added to supplement penicillin therapy. Patient stabilized over one week and was transferred out of the intensive care unit. Streptococcal toxic shock syndrome is distinctly different from Staphylococcal toxic shock syndrome, besides different bacterial genus, in that it is always associated with a desquamating rash as the prevalent feature and essential for diagnosis. Rash is not required for STSS. It is essential to remember that both Streptococcal and Staphylococcal toxic shock syndrome carry a high mortality rate and that suspicion clinically should warrant a thorough check for source (foreign body, radiology, cultures) as well as antibiotic therapy with beta lactams as well as clindamycin. Studies report that a high concentration of GAS leads to a loss of beta lactam binding sites, thus decreasing its efficacy(4). This highlights the importance of adding clindamycin, as it is not affected by the concentration of GAS, suppresses the exotoxin production, increases host phagocytosis and has been shown retrospectively to be associated with better outcomes(5).

A diversity profile from the staphylococcal community on atopic dermatitis skin: a molecular approach

The aim of this study was to determine the biodiversity of the skin staphylococcal community from patients with atopic dermatitis (AD) and superantigen (SAg) detection from Staphylococcus aureus isolates. In this study, we developed a novel multiplex PCR that allows the identification and discrimination of bacteria belonging to the Staphylococcus genus both Staph.aureus and coagulase-negative Staphylococcus - Staph.capitis, Staph.epidermidis, Staph.haemolyticus and Staph.hominis isolated from the skin of patients with AD. In addition, a multiplex PCR assay that allows the rapid screening of the 19 genes that encode staphylococcal enterotoxins (SEs), SE-like toxins and toxic shock syndrome toxin-1 was also performed and applied in Staph.aureus isolates. The microflora of the skin of patients with AD was dominated by Staph.aureus (69 isolates, 35·6%) followed by Staph.epidermidis (59 isolates, 30·4%) species. The SElM and SElN genes were the most frequently detected in our study (15 isolates, 71·4%), followed by SEG and SElO (14 isolates, 66·7%). Our molecular-based approach successfully identified the staphylococcal microflora that was relatively specific to patients with AD. Considering skin colonization and expression of virulence factors, the Staph.aureus may play a relevant role in AD pathophysiology. This ability to classify disease-related microbial species provides new insights into the relevance of those microbes in human disorders.

A fatal case of staphylococcal toxic shock syndrome

Staphylococcal toxic shock syndrome (STSS) is an uncommon but potentially fatal disease with multisystem involvement. It occurs due to production of TSS Toxin-1 (TSST-1) by Staphylococcus aureus that induces a severe immunologically mediated inflammatory response affecting multiple organ systems and thereby mimics various diseases causing similar clinical picture. A high degree of clinical suspicion and prompt management is necessary to avoid fatality.1 Herein we report a case encountered in our hospital.

Skin Findings of Staphylococcus aureus Toxin-mediated Infection in Relation to Toxin Encoding Genes

Staphylococcal scalded skin syndrome and toxic shock syndrome are associated with exfoliatins and superantigens, respectively; and are easy to distinguish in their usual presentation. However, there is confusion about the mild forms of these 2 staphylococcal diseases. These mild forms are both designated as "staphylococcal scarlet fever" despite differences in their pathophysiology and clinical presentation. Our study aimed to distinguish between the clinical characteristics of the rash associated with exfoliatins and the rash associated with superantigens. Patients were selected from the French National Reference Center for Staphylococci. We retrospectively compared the clinical characteristics of patients with a generalized rash during Staphylococcus aureus infection. Patients who met the criteria of staphylococcal scalded skin syndrome or toxic shock syndrome were excluded. The patients were classified into 2 groups depending on the presence of a gene coding for exfoliatin or for superantigenic toxin. We included 13 cases with exfoliatin and 9 with superantigens. The patients of the exfoliatin group were more likely to have facial involvement, fold involvement and a superficial focus of infection. In the second group, S. aureus was isolated from a deeper focus in 8 of 9 patients. Mild forms of S. aureus toxin-mediated infection affect the pediatric population. Examination made it possible to distinguish an exanthema associated with an exfoliatin from one associated with a superantigen. This early clinical distinction results in differences in management.

Editorial introductions

Current Opinion in Infectious Diseases was launched in 1988. It is part of a successful series of review journals whose unique format is designed to provide a systematic and critical assessment of the literature as presented in the many primary journals. The field of infectious diseases is divided into 11 sections that are reviewed once a year. Each section is assigned a Section Editor, a leading authority in the area, who identifies the most important topics at that time. Here we are pleased to introduce the Section Editors for this issue. SECTION EDITORS Paul T. HeathPaul T. HeathPaul Heath is a Professor and Honorary Consultant in Paediatric Infectious Diseases at St George's, University of London and Vaccine Institute in London, UK. His training in paediatrics and infectious diseases was at the Royal Children's Hospital, Melbourne, Australia, the John Radcliffe Hospital, Oxford, UK and St George's Hospital, London, UK. His particular research interests are in the epidemiology of vaccine preventable diseases, in clinical vaccine trials, particularly in at-risk groups, and in perinatal infections. He sits on national committees concerned with meningitis, group B streptococcus prevention and on immunisation policies in children. He is a Fellow of the Royal Australasian College of Physicians, a Fellow of the Royal College of Paediatrics and Child Health, a member of the education committee of the European Society of Paediatric Infectious Diseases and a member of the Science Board of the international Brighton Collaboration on vaccine safety. Dennis L. StevensDennis L. StevensDr Stevens received his PhD in Microbiology from Montana State University, USA and his MD from the University of Utah College of Medicine, USA. Following a residency in internal medicine at the University of Utah, Dr Stevens completed an infectious disease fellowship at Brooke Army Medical Center in San Antonio, Texas, USA and has been Chief of Infectious Diseases at the Veterans Affairs Medical Center in Boise, Idaho, USA, since 1979. Dr Stevens is Professor of Medicine at the University of Washington School of Medicine, USA and his major clinical interests have been in Staphylococcal and Streptococcal toxic shock syndromes and in skin and soft tissue infections including necrotizing fasciitis and gas gangrene. His research interests are centered around gram positive bacteria and the role of extracellular toxins in the pathogenesis of severe soft tissue infection caused by Streptococcus pyogenes, Clostridium perfringens and methicillin-resistant Staphylococcus aureus. Current research efforts investigate the mechanisms of toxin induced shock and organ dysfunction, the effects of toxins on endothelial cells, granulocytes and platelets and the importance of the mechanisms of action of antibiotics in treating gram positive infections. Dr Stevens has published over 150 original research papers, 60 book chapters, 110 abstracts and two books, Streptococcal Infections: Clinical Aspects, Microbiology and Molecular Pathogenesis (co-authored with Dr. Edward Kaplan) and An Atlas of Infectious Diseases: Skin and Soft Tissue, Bone and Joint Infections. Dr Stevens is a member of the American Society of Microbiology, a Fellow in the American College of Physicians, a Fellow in the Infectious Disease Society of America and a member of the Association of American Physicians. In 2000, Dr Stevens received the Infectious Disease Society of America's Society Citation Award and in 2001, The William Altemier Award from the Surgical Infectious Disease Society. Dr Stevens has served as a consultant for the Centers of Disease Control and PreventionWorking Group on Invasive Group A streptococcal infections and for the World Health Organization and National Institutes of Health on similar matters. Dr Stevens is currently Chairman of the Infectious Disease Society of America Guidelines Committee on Skin and Soft Tissue Infections.

Identification of Toxic Shock Syndrome Toxin-1 (TSST-1) gene in Staphylococcus aureus isolated from bovine mastitis milk

Staphylococcus aureus is a major causative pathogen of clinical and subclinical mastitis of dairy domestic ruminants. This agent produces a variety of extracellular toxins and virulence factors including Toxic Shock Syndrome Toxin-1 (TSST-1) which is the major cause of Toxic Shock Syndrome (TSS). In this study 58 S. aureus isolates obtained from 9 dairy herds in East and West Azerbaijan provinces of Iran. The tested isolates were identified on the basis of the cultural and biochemical properties as well as by amplification of the aroA gene, specific to S. aureus. Isolates were also analyzed for the presence of the TSST-1 encoding gene (tst) using Polymerase Chain Reaction (PCR). tst gene 350 bp was detected in 9 (15.5%) of the total number of 58 isolates. The present study revealed that the PCR amplification of the aroA gene could be used as a powerful tool for identification of S. aureus from the cases of bovine mastitis. Results also showed that the strain of S. aureus which caused mastitis can potentially produce staphylococcal toxic shock syndrome toxin-1. Overall, our results suggest that it is of special importance to follow the presence of TSST-1 producing S. aureus in foodstuffs, especially for protecting the consumers from toxic shock syndrome.

Vaccination with Plasmid DNA Encoding a Mutant Toxic Shock Syndrome Toxin-1 Ameliorates Toxin-induced Lethal Shock in Mice

Staphylococcal toxic shock syndrome toxin-1 (TSST-1), a superantigenic toxin produced by Staphylococcus (S.) aureus, is a major cause of septic shock and toxic shock syndrome. To investigate whether vaccination with a plasmid DNA encoding a non-toxic mutant TSST-1 (mTSST-1) can protect mice against wild-type TSST-1-induced lethal shock, the mice were intranasally immunized with the plasmid DNA (named pcDNA-mTSST-1) plus a mucosal adjuvant, a non-toxic mutant labile toxin (mLT). After the immunization, the mice were challenged with TSST-1 and lipopolysaccharide (LPS). The survival rate of mice immunized with pcDNA-mTSST-1 plus mLT was higher than that of the control mice immunized with PBS alone, mLT alone, pcDNA-mTSST-1 alone, or a parent plasmid plus mLT. The titers of interferon-γ (IFN-γ) in the sera of mice immunized with pcDNA-mTSST-1 plus mLT were significantly lower than those of the mLT control mice. Immunization with pcDNA-mTSST-1 plus mLT increased the serum levels of TSST-1-specific antibodies, especially immunoglobulin G1 (IgG1) and IgG2a subclasses. Furthermore, the sera obtained from mice immunized with pcDNA-mTSST-1 plus mLT significantly inhibited the TSST-1-induced secretion of IFN-γ and tumor necrosis factor-α (TNF-α) in murine spleen cells in vitro. These results indicate that immunization with pcDNA-mTSST-1 plus mLT provides protection against the lethal toxic shock of mice induced by wild-type TSST-1. The protective effect could be due to TSST-1-specific neutralizing antibodies as well as the inhibition of IFN-γ and TNF-α secretions. Since TSST-1 is commonly released by invasive S. aureus, the pcDNA-mTSST-1 should be useful in preventing toxin-induced shock resulting from S. aureus infection.

Detrimental effects of T regulatory cell-promoting IL-2-anti-IL-2 complexes in staphylococcal toxic shock syndrome. (164.13)

Abstract Menstrual or non-menstrual toxic shock syndrome (TSS), caused by the superantigen exotoxins of Staphylococcus aureus or Streptococcus pyogenes, is characterized by a robust activation of the immune system, systemic cytokine/chemokine storm, multiple organ failure and possibly death, if not treated promptly. We tested whether increasing the numbers of Treg in vivo by administration of IL-2-anti-IL-2 complexes (IL2C) could be beneficial in TSS. Administration of IL2C [prepared by incubating 1µg of IL-2 (Peprotech) and 5µg anti-IL-2 (eBioscience, clone-JES6-1A12) in a total 200 µl at 37oC for 30 min] on days 0, 1 and 2, caused a 3 to 4-fold increase in CD4+CD25+FoxP3+ Treg numbers in the spleens of HLA-DR3 transgenic mice by day 5. However, upon challenge with staphylococcal enterotoxin B (SEB, 50µg), compared to untreated HLA-DR3 transgenic mice, IL2C-treated mice produced significantly higher levels of IFN-γ (1714±1365 versus 6642±2253 pg/ml), MIP-1α (782±23 versus 2305±376 pg/ml,), MIP-1β, RANTES and TNF-α. SEB-induced mortality was also significantly increased in the IL2C treated group. While only 1/5 mice died in untreated group, 6/11 mice died in the IL2C treated group. In conclusion, even though administration of IL2C significantly increased the Treg numbers, such a treatment also increased their susceptibility to TSS. Hence, the benefits of T reg-promoting IL-2-anti-IL-2 complexes in TSS or related conditions need more stringent evaluation.

Application of a Chimeric Protein Construct having Enterotoxin B and Toxic Shock Syndrome Toxin Domains of S. aureus in Immunodiagnostics

Staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin-1 are the super antigens responsible for diseases such as staphylococcal food poisoning and toxic shock syndrome. At low serum concentrations, SEB can trigger toxic shock, profound hypotension and multi organ failure and hence is recognized as biowarfare molecule. In this study, a multidomain fusion protein (r-TE) was generated with specificity for SEB and toxic shock syndrome toxin (Tsst-1). The fusion gene comprising the conserved regions of seb and the tsst genes was codon-optimized for expression in Escherichia coli and encoded a 26kDa recombinant multidomain chimeric protein (r-TE). Hyperimmune antiserum raised against r-TE specifically reacted with SEB (~28kDa) and Tsst-1 (~22kDa) components during Western blot analysis and by plate ELISA in confirmed toxin producing strains of S. aureus. The antigenicity of the SEB component of the r-TE protein was also confirmed using TECRA kit. The described procedure of creating a single protein molecule carrying components of two different toxins whilst still retaining the original antigenic determinants of individual toxins proved highly advantageous in the development of rapid, reliable and cost effective immunoassays and may also have the potential to serve as candidate molecule for vaccine studies.

Epithelial Proinflammatory Response and Curcumin-Mediated Protection from Staphylococcal Toxic Shock Syndrome Toxin-1

Staphylococcus aureus initiates infections and produces virulence factors, including superantigens (SAgs), at mucosal surfaces. The SAg, Toxic Shock Syndrome Toxin-1 (TSST-1) induces cytokine secretion from epithelial cells, antigen presenting cells (APCs) and T lymphocytes, and causes toxic shock syndrome (TSS). This study investigated the mechanism of TSST-1-induced secretion of proinflammatory cytokines from human vaginal epithelial cells (HVECs) and determined if curcumin, an anti-inflammatory agent, could reduce TSST-1-mediated pathology in a rabbit vaginal model of TSS. TSST-1 caused a significant increase in NF-κB-dependent transcription in HVECs that was associated with increased expression of TNF- α, MIP-3α, IL-6 and IL-8. Curcumin, an antagonist of NF-κB-dependent transcription, inhibited IL-8 production from ex vivo porcine vaginal explants at nontoxic doses. In a rabbit model of TSS, co-administration of curcumin with TSST-1 intravaginally reduced lethality by 60% relative to 100% lethality in rabbits receiving TSST-1 alone. In addition, TNF-α was undetectable from serum or vaginal tissue of curcumin treated rabbits that survived. These data suggest that the inflammatory response induced at the mucosal surface by TSST-1 is NF-κB dependent. In addition, the ability of curcumin to prevent TSS in vivo by co-administration with TSST-1 intravaginally suggests that the vaginal mucosal proinflammatory response to TSST-1 is important in the progression of mTSS.

Evolutionary blueprint for host- and niche-adaptation in Staphylococcus aureus clonal complex CC30

Staphylococcus aureus clonal complex CC30 has caused infectious epidemics for more than 60 years, and, therefore, provides a model system to evaluate how evolution has influenced the disease potential of closely related strains. In previous multiple genome comparisons, phylogenetic analyses established three major branches that evolved from a common ancestor. Clade 1, comprised of historic pandemic phage type 80/81 methicillin susceptible S. aureus (MSSA), and Clade 2 comprised of contemporary community acquired methicillin resistant S. aureus (CA-MRSA) were hyper-virulent in murine infection models. Conversely, Clade 3 strains comprised of contemporary hospital associated MRSA (HA-MRSA) and clinical MSSA exhibited attenuated virulence, due to common single nucleotide polymorphisms (SNP's) that abrogate production of α-hemolysin Hla, and interfere with signaling of the accessory gene regulator agr. We have now completed additional in silico genome comparisons of 15 additional CC30 genomes in the public domain, to assess the hypothesis that Clade 3 has evolved to favor niche adaptation. In addition to SNP's that influence agr and hla, other common traits of Clade 3 include tryptophan auxotrophy due to a di-nucleotide deletion within trpD, a premature stop codon within isdH encoding an immunogenic cell surface protein involved in iron acquisition, loss of a genomic toxin–antitoxin (TA) addiction module, acquisition of S. aureus pathogenicity islands SaPI4, and SaPI2 encoding toxic shock syndrome toxin tst, and increased copy number of insertion sequence ISSau2, which appears to target transcription terminators. Compared to other Clade 3 MSSA, S. aureus MN8, which is associated with Staphylococcal toxic shock syndrome, exhibited a unique ISSau2 insertion, and enhanced production of toxic shock syndrome toxin encoded by SaPI2. Cumulatively, our data support the notion that Clade 3 strains are following an evolutionary blueprint toward niche-adaptation.

Clinical Features and Etiology of Adult Patients with Fever and Rash

BackgroundPatients with fever and rash often pose an urgent diagnostic and therapeutic dilemma for the clinician. The nonspecificity of many fever and rash syndromes mandates a systemic approach to diagnosis.ObjectiveWe aimed to determine the etiology of fever and rash in 100 adult patients followed-up as in- or outpatients prospectively.MethodsAll the patients, who presented with rash and fever, were followed-up prospectively and their clinical and laboratory studies were evaluated.ResultsThe median age was 35 years (14~79 years); 45 were female and 55 were male. Patients were divided into 3 groups according to the etiology: infectious (50%), noninfectious (40%) and undiagnosed (10%). The most common type of rash was maculopapular, and the most common 5 causes were measles, cutaneous drug reactions, varicella, adult-onset Still's disease (ASD) and rickettsial disease. Viral diseases among infectious causes and cutaneous drug reactions, among the noninfectious causes, were determined as the main diseases. The mortality rate was 5% and the reasons of mortality were as follows: toxic epidermal necrolysis (2 patients), ASD (1), staphylococcal toxic shock syndrome (1) and graft-versus-host disease (1).ConclusionAdult patients with fever and rash had a wide differential diagnosis. The most common type of rash was determined as maculopapular, and the most frequent five diseases were measles, drug reactions, chickenpox, ASD and rickettsial infection. Viral diseases among infectious causes and drug reactions among noninfectious causes were determined as the leading etiologies.

Staphylococcal Toxic Shock Syndrome 2000–2006: Epidemiology, Clinical Features, and Molecular Characteristics

IntroductionCirculating strains of Staphylococcus aureus (SA) have changed in the last 30 years including the emergence of community-associated methicillin-resistant SA (MRSA). A report suggested staphylococcal toxic shock syndrome (TSS) was increasing over 2000–2003. The last population-based assessment of TSS was 1986.MethodsPopulation-based active surveillance for TSS meeting the CDC definition using ICD-9 codes was conducted in the Minneapolis-St. Paul area (population 2,642,056) from 2000–2006. Medical records of potential cases were reviewed for case criteria, antimicrobial susceptibility, risk factors, and outcome. Superantigen PCR testing and PFGE were performed on available isolates from probable and confirmed cases.ResultsOf 7,491 hospitalizations that received one of the ICD-9 study codes, 61 TSS cases (33 menstrual, 28 non-menstrual) were identified. The average annual incidence per 100,000 of all, menstrual, and non-menstrual TSS was 0.52 (95% CI, 0.32–0.77), 0.69 (0.39–1.16), and 0.32 (0.12–0.67), respectively. Women 13–24 years had the highest incidence at 1.41 (0.63–2.61). No increase in incidence was observed from 2000–2006. MRSA was isolated in 1 menstrual and 3 non-menstrual cases (7% of TSS cases); 1 isolate was USA400. The superantigen gene tst-1 was identified in 20 (80%) of isolates and was more common in menstrual compared to non-menstrual isolates (89% vs. 50%, p = 0.07). Superantigen genes sea, seb and sec were found more frequently among non-menstrual compared to menstrual isolates [100% vs 25% (p = 0.4), 60% vs 0% (p<0.01), and 25% vs 13% (p = 0.5), respectively].DiscussionTSS incidence remained stable across our surveillance period of 2000–2006 and compared to past population-based estimates in the 1980s. MRSA accounted for a small percentage of TSS cases. tst-1 continues to be the superantigen associated with the majority of menstrual cases. The CDC case definition identifies the most severe cases and has been consistently used but likely results in a substantial underestimation of the total TSS disease burden.