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Cieza MYR, Bonsaglia ECR, Rall VLM, dos Santos MV, Silva NCC. Staphylococcal Enterotoxins: Description and Importance in Food. Pathogens 2024; 13:676. [PMID: 39204276 PMCID: PMC11357529 DOI: 10.3390/pathogens13080676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/31/2024] [Accepted: 08/01/2024] [Indexed: 09/03/2024] Open
Abstract
Staphylococcus aureus stands out as one of the most virulent pathogens in the genus Staphylococcus. This characteristic is due to its ability to produce a wide variety of staphylococcal enterotoxins (SEs) and exotoxins, which in turn can cause staphylococcal food poisoning (SFP), clinical syndromes such as skin infections, inflammation, pneumonia, and sepsis, in addition to being associated with the development of inflammation in the mammary glands of dairy cattle, which results in chronic mastitis and cell necrosis. SEs are small globular proteins that combine superantigenic and emetic activities; they are resistant to heat, low temperatures, and proteolytic enzymes and are tolerant to a wide pH range. More than 24 SE genes have been well described (SEA-SEE, SEG, SEH, SEI, SEJ, SElK, SElL, SElM, SElN, SElO, SElP, SElQ, SElR, SElS, SElT, SElU, SElV, SElW, SElX, SElY, and SElZ), being a part of different SFP outbreaks, clinical cases, and isolated animal strains. In recent years, new genes (sel26, sel27, sel28, sel31, sel32, and sel33) from SEs have been described, as well as two variants (seh-2p and ses-3p) resulting in a total of thirty-three genes from Ses, including the nine variants that are still in the process of genetic and molecular structure evaluation. SEs are encoded by genes that are located in mobile genetic elements, such as plasmids, prophages, pathogenicity islands, and the enterotoxin gene cluster (egc), and housed in the genomic island of S. aureus. Both classical SEs and SE-like toxins (SEls) share phylogenetic relationships, structure, function, and sequence homology, which are characteristics for the production of new SEs through recombination processes. Due to the epidemiological importance of SEs, their rapid assessment and detection have been crucial for food security and public health; for this reason, different methods of identification of SEs have been developed, such as liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS), molecular methods, and whole-genome sequencing; providing the diagnosis of SEs and a better understanding of the occurrence, spread, and eradication of SEs. This review provides scientific information on the enterotoxins produced by S. aureus, such as structural characteristics, genetic organization, regulatory mechanisms, superantigen activity, mechanisms of action used by SEs at the time of interaction with the immune system, methods of detection of SEs, and recent biocontrol techniques used in food.
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Affiliation(s)
- Mirian Yuliza Rubio Cieza
- Department of Food Science and Nutrition, School of Food Engineering, University of Campinas (UNICAMP), Campinas 13083-862, Brazil;
| | - Erika Carolina Romão Bonsaglia
- Department of Animal Nutrition and Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo (USP), Pirassununga 13635-900, Brazil; (E.C.R.B.); (M.V.d.S.)
| | - Vera Lucia Mores Rall
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University, Botucatu 18618-691, Brazil;
| | - Marcos Veiga dos Santos
- Department of Animal Nutrition and Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo (USP), Pirassununga 13635-900, Brazil; (E.C.R.B.); (M.V.d.S.)
| | - Nathália Cristina Cirone Silva
- Department of Food Science and Nutrition, School of Food Engineering, University of Campinas (UNICAMP), Campinas 13083-862, Brazil;
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Rahman S, Sarkar K, Das AK. Exploring staphylococcal superantigens to design a potential multi-epitope vaccine against Staphylococcus aureus: an in-silico reverse vaccinology approach. J Biomol Struct Dyn 2023; 41:13098-13112. [PMID: 36729064 DOI: 10.1080/07391102.2023.2171138] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/13/2023] [Indexed: 02/03/2023]
Abstract
Staphylococcus aureus is a horrifying bacteria capable of causing millions of deaths yearly across the globe. A major contribution to the success of S. aureus as an ESKAPE pathogen is the abundance of virulence factors that can manipulate the innate and adaptive immune system of the individual. Currently, no vaccine is available to treat S. aureus-mediated infections. In this study, we present in-silico approaches to design a stable, safe and immunogenic vaccine that could help to control the infections associated with the bacteria. Three vital pathogenic secreted toxins of S. aureus, such as staphylococcal enterotoxin A (SEA), staphylococcal enterotoxin B (SEB), Toxic-shock syndrome toxin (TSST-1), were selected using the reverse vaccinology approach to design the multi-epitope vaccine (MEV). Linear B-lymphocyte, cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes were predicted from these selected proteins. For designing the multi-epitope vaccine (MEV), B-cell epitopes were joined with the KK linker, CTL epitopes were joined with the AAY linker, and HTL epitopes were joined with the GPGPG linker. Finally, to increase the immune response to the vaccine, a human β-defensin-3 (hBD-3) adjuvant was added to the N-terminus of the MEV construct. The final MEV was found to be antigenic and non-allergen in nature. In-silico immune simulation and cloning analysis predicted the immune-stimulating potential of the designed MEV construct along with the cloning feasibility in the pET28a(+) vector with the E. coli expression system. This immunoinformatics study provides a platform for designing a suitable, safe and effective vaccine against S. aureus.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Shakilur Rahman
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Kasturi Sarkar
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Amit Kumar Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
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Noli Truant S, Redolfi DM, Sarratea MB, Malchiodi EL, Fernández MM. Superantigens, a Paradox of the Immune Response. Toxins (Basel) 2022; 14:toxins14110800. [PMID: 36422975 PMCID: PMC9692936 DOI: 10.3390/toxins14110800] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/27/2022] [Accepted: 10/27/2022] [Indexed: 11/19/2022] Open
Abstract
Staphylococcal enterotoxins are a wide family of bacterial exotoxins with the capacity to activate as much as 20% of the host T cells, which is why they were called superantigens. Superantigens (SAgs) can cause multiple diseases in humans and cattle, ranging from mild to life-threatening infections. Almost all S. aureus isolates encode at least one of these toxins, though there is no complete knowledge about how their production is triggered. One of the main problems with the available evidence for these toxins is that most studies have been conducted with a few superantigens; however, the resulting characteristics are attributed to the whole group. Although these toxins share homology and a two-domain structure organization, the similarity ratio varies from 20 to 89% among different SAgs, implying wide heterogeneity. Furthermore, every attempt to structurally classify these proteins has failed to answer differential biological functionalities. Taking these concerns into account, it might not be appropriate to extrapolate all the information that is currently available to every staphylococcal SAg. Here, we aimed to gather the available information about all staphylococcal SAgs, considering their functions and pathogenicity, their ability to interact with the immune system as well as their capacity to be used as immunotherapeutic agents, resembling the two faces of Dr. Jekyll and Mr. Hyde.
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Liu C, Shen Y, Yang M, Chi K, Guo N. Hazard of Staphylococcal Enterotoxins in Food and Promising Strategies for Natural Products against Virulence. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:2450-2465. [PMID: 35170308 DOI: 10.1021/acs.jafc.1c06773] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Staphylococcal enterotoxins (SEs) secreted by Staphylococcus aureus frequently contaminate food and cause serious foodborne diseases but are ignored during food processing and even cold-chain storage. Notably, SEs are stable and resistant to harsh sterilization environments, which can induce more serious hazards to public health than the bacterium itself. Therefore, it is necessary to develop promising strategies to control SE contamination in food and improve food safety. Natural products not only have various pharmaceutical properties, such as antimicrobial and antitoxin activities, but they are also eco-friendly, safe, nutritive, and barely drug-resistant. Here, the hazards of SEs and the promising natural compounds with different inhibitory mechanisms are summarized and classified. The key points of future research and applications for natural products against bacterial toxin contamination in food are also prospected. Overall, this review may provide enlightening insights for screening effective natural compounds to prevent foodborne diseases caused by bacterial toxins.
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Affiliation(s)
- Chunmei Liu
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Yong Shen
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Meng Yang
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Kunmei Chi
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Na Guo
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
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Uzunҫayır S, Vera‐Rodriguez A, Regenthal P, Åbacka H, Emanuelsson C, Bahl CD, Lindkvist‐Petersson K. Analyses of the complex formation of staphylococcal enterotoxin A and the human gp130 cytokine receptor. FEBS Lett 2022; 596:910-923. [DOI: 10.1002/1873-3468.14292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/14/2021] [Accepted: 01/10/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Sibel Uzunҫayır
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
| | - Arturo Vera‐Rodriguez
- Institute for Protein Innovation Boston USA
- Division of Hematology‐Oncology, Boston Children’s Hospital Harvard Medical School Boston USA
| | - Paulina Regenthal
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
| | - Hannah Åbacka
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
| | - Cecilia Emanuelsson
- Department of Chemistry Division for Biochemistry and Structural Biology Lund University Lund Sweden
| | - Christopher D. Bahl
- Institute for Protein Innovation Boston USA
- Division of Hematology‐Oncology, Boston Children’s Hospital Harvard Medical School Boston USA
| | - Karin Lindkvist‐Petersson
- Department of Experimental Medical Science Lund University BMC C13 22 184 Lund Sweden
- LINXS ‐ Lund Institute of Advanced Neutron and X‐ray Science Scheelevägen 19 SE‐223 70 Lund Sweden
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Hu DL, Li S, Fang R, Ono HK. Update on molecular diversity and multipathogenicity of staphylococcal superantigen toxins. ANIMAL DISEASES 2021. [DOI: 10.1186/s44149-021-00007-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
AbstractStaphylococcal superantigen (SAg) toxins are the most notable virulence factors associated with Staphylococcus aureus, which is a pathogen associated with serious community and hospital acquired infections in humans and various diseases in animals. Recently, SAg toxins have become a superfamily with 29 types, including staphylococcal enterotoxins (SEs) with emetic activity, SE-like toxins (SEls) that do not induce emesis in primate models or have yet not been tested, and toxic shock syndrome toxin-1 (TSST-1). SEs and SEls can be subdivided into classical types (SEA to SEE) and novel types (SEG to SElY, SE01, SE02, SEl26 and SEl27). The genes of SAg toxins are located in diverse accessory genetic elements and share certain structural and biological properties. SAg toxins are heat-stable proteins that exhibit pyrogenicity, superantigenicity and capacity to induce lethal hypersensitivity to endotoxin in humans and animals. They have multiple pathogenicities that can interfere with normal immune function of host, increase the chances of survival and transmission of pathogenic bacteria in host, consequently contribute to the occurrence and development of various infections, persistent infections or food poisoning. This review focuses on the following aspects of SAg toxins: (1) superfamily members of classic and novelty discovered staphylococcal SAgs; (2) diversity of gene locations and molecular structural characteristics; (3) biological characteristics and activities; (4) multi-pathogenicity of SAgs in animal and human diseases, including bovine mastitis, swine sepsis, abscesses and skin edema in pig, arthritis and septicemia in poultry, and nosocomial infections and food-borne diseases in humans.
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Abstract
Staphylococcus aureus and Streptococcus pyogenes are common human pathogens, causing infections that include the skin. Both pathogens produce a family of secreted toxins called superantigens, which have been shown to be important in human diseases. The first cell types encountered by superantigens on skin are keratinocytes. Our studies demonstrated, that the human keratinocyte pathway, among other pathways, responds to superantigens with production of chemokines, setting off inflammation. This inflammatory response may be harmful, facilitating opening of the skin barrier. Staphylococcus aureus and Streptococcus pyogenes are significant human pathogens, causing infections at multiple body sites, including across the skin. Both are organisms that cause human diseases and secrete superantigens, including toxic shock syndrome toxin-1 (TSST-1), staphylococcal enterotoxins (SEs), and streptococcal pyrogenic exotoxins (SPEs). On the skin, human keratinocytes represent the first cell type to encounter these superantigens. We employed transcriptome sequencing (RNA-seq) to evaluate the human primary keratinocyte response to both TSST-1 and staphylococcal enterotoxin B (SEB) in triplicate analyses. Both superantigens caused large numbers of genes to be up- and downregulated. The genes that exhibited 2-fold differential gene expression compared to vehicle-treated cells, whether up- or downregulated, totaled 5,773 for TSST-1 and 4,320 for SEB. Of these, 4,482 were significantly upregulated by exposure of keratinocytes to TSST-1, whereas 1,291 were downregulated. For SEB, expression levels of 3,785 genes were upregulated, whereas those of 535 were downregulated. There was the expected high overlap in both upregulation (3,412 genes) and downregulation (400 genes). Significantly upregulated genes included those associated with chemokine production, with the possibility of stimulation of inflammation. We also tested an immortalized human keratinocyte line, from a different donor, for chemokine response to four superantigens. TSST-1 and SEB caused production of interleukin-8 (IL-8), MIP-3α, and IL-33. SPEA and SPEC were evaluated for stimulation of expression of IL-8 as a representative chemokine; both stimulated production of IL-8. IMPORTANCEStaphylococcus aureus and Streptococcus pyogenes are common human pathogens, causing infections that include the skin. Both pathogens produce a family of secreted toxins called superantigens, which have been shown to be important in human diseases. The first cell types encountered by superantigens on skin are keratinocytes. Our studies demonstrated, that the human keratinocyte pathway, among other pathways, responds to superantigens with production of chemokines, setting off inflammation. This inflammatory response may be harmful, facilitating opening of the skin barrier.
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Etter D, Schelin J, Schuppler M, Johler S. Staphylococcal Enterotoxin C-An Update on SEC Variants, Their Structure and Properties, and Their Role in Foodborne Intoxications. Toxins (Basel) 2020; 12:E584. [PMID: 32927913 PMCID: PMC7551944 DOI: 10.3390/toxins12090584] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/20/2022] Open
Abstract
Staphylococcal enterotoxins are the most common cause of foodborne intoxications (staphylococcal food poisoning) and cause a wide range of diseases. With at least six variants staphylococcal enterotoxin C (SEC) stands out as particularly diverse amongst the 25 known staphylococcal enterotoxins. Some variants present unique and even host-specific features. Here, we review the role of SEC in human and animal health with a particular focus on its role as a causative agent for foodborne intoxications. We highlight structural features unique to SEC and its variants, particularly, the emetic and superantigen activity, as well as the roles of SEC in mastitis and in dairy products. Information about the genetic organization as well as regulatory mechanisms including the accessory gene regulator and food-related stressors are provided.
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Affiliation(s)
- Danai Etter
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, 8057 Zürich, Switzerland;
- Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland;
| | - Jenny Schelin
- Division of Applied Microbiology, Department of Chemistry, Lund University, 22100 Lund, Sweden;
| | - Markus Schuppler
- Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zürich, 8092 Zürich, Switzerland;
| | - Sophia Johler
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, 8057 Zürich, Switzerland;
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Zeng C, Liu Z, Han Z. Structure of Staphylococcal Enterotoxin N: Implications for Binding Properties to Its Cellular Proteins. Int J Mol Sci 2019; 20:ijms20235921. [PMID: 31775346 PMCID: PMC6928602 DOI: 10.3390/ijms20235921] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 01/26/2023] Open
Abstract
Staphylococcus aureus strains produce a unique family of immunostimulatory exotoxins termed as bacterial superantigens (SAgs), which cross-link major histocompatibility complex class II (MHC II) molecule and T-cell receptor (TCR) to stimulate large numbers of T cells at extremely low concentrations. SAgs are associated with food poisoning and toxic shock syndrome. To date, 26 genetically distinct staphylococcal SAgs have been reported. This study reports the first X-ray structure of newly characterized staphylococcal enterotoxin N (SEN). SEN possesses the classical two domain architecture that includes an N-terminal oligonucleotide-binding fold and a C-terminal β-grasp domain. Amino acid and structure alignments revealed that several critical amino acids that are proposed to be responsible for MHC II and TCR molecule engagements are variable in SEN, suggesting that SEN may adopt a different binding mode to its cellular receptors. This work helps better understand the mechanisms of action of SAgs.
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Affiliation(s)
- Chi Zeng
- College of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China; (C.Z.); (Z.L.)
- Hubei Province Fresh Food Engineering Research Center, Wuhan Polytechnic University, Wuhan 430023, China
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Zhaoxin Liu
- College of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China; (C.Z.); (Z.L.)
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zhenggang Han
- College of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China; (C.Z.); (Z.L.)
- Correspondence:
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Suzuki Y. Current Studies of Staphylococcal Food Poisoning. Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) 2019; 60:27-37. [DOI: 10.3358/shokueishi.60.27] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Fisher EL, Otto M, Cheung GYC. Basis of Virulence in Enterotoxin-Mediated Staphylococcal Food Poisoning. Front Microbiol 2018; 9:436. [PMID: 29662470 PMCID: PMC5890119 DOI: 10.3389/fmicb.2018.00436] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/26/2018] [Indexed: 12/17/2022] Open
Abstract
The Staphylococcus aureus enterotoxins are a superfamily of secreted virulence factors that share structural and functional similarities and possess potent superantigenic activity causing disruptions in adaptive immunity. The enterotoxins can be separated into two groups; the classical (SEA-SEE) and the newer (SEG-SElY and counting) enterotoxin groups. Many members from both these groups contribute to the pathogenesis of several serious human diseases, including toxic shock syndrome, pneumonia, and sepsis-related infections. Additionally, many members demonstrate emetic activity and are frequently responsible for food poisoning outbreaks. Due to their robust tolerance to denaturing, the enterotoxins retain activity in food contaminated previously with S. aureus. The genes encoding the enterotoxins are found mostly on a variety of different mobile genetic elements. Therefore, the presence of enterotoxins can vary widely among different S. aureus isolates. Additionally, the enterotoxins are regulated by multiple, and often overlapping, regulatory pathways, which are influenced by environmental factors. In this review, we also will focus on the newer enterotoxins (SEG-SElY), which matter for the role of S. aureus as an enteropathogen, and summarize our current knowledge on their prevalence in recent food poisoning outbreaks. Finally, we will review the current literature regarding the key elements that govern the complex regulation of enterotoxins, the molecular mechanisms underlying their enterotoxigenic, superantigenic, and immunomodulatory functions, and discuss how these activities may collectively contribute to the overall manifestation of staphylococcal food poisoning.
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Affiliation(s)
- Emilie L Fisher
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
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Hu DL, Ono HK, Isayama S, Okada R, Okamura M, Lei LC, Liu ZS, Zhang XC, Liu MY, Cui JC, Nakane A. Biological characteristics of staphylococcal enterotoxin Q and its potential risk for food poisoning. J Appl Microbiol 2017; 122:1672-1679. [PMID: 28375567 DOI: 10.1111/jam.13462] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/08/2017] [Accepted: 03/24/2017] [Indexed: 11/30/2022]
Abstract
AIMS To elucidate the biological characteristics and stability of a newly identified staphylococcal enterotoxin Q (SEQ) against heating and digestive enzymes and to evaluate the risk of seq-harbouring Staphylococcus aureus in food poisoning. METHODS AND RESULTS Purified SEQ was treated with heating, pepsin and trypsin which are related to food cooking, stomach and intestine conditions, respectively. Superantigenic activity of SEQ was assessed by determining the ability of IL-2 induction in mouse spleen cells. The emetic activity of SEQ was assessed using house musk shrew, a small emetic animal model. The results revealed that SEQ exhibits a remarkable resistance to heat treatment and pepsin digestion and has significant superantigenic and emetic activities. Furthermore, a sandwich ELISA for detection of SEQ production was developed, and the results showed that seq-harboring S. aureus isolates produce a large amount of SEQ. CONCLUSIONS The newly identified SEQ had remarkable stability to heat treatment and digestive enzyme degradation and exhibited significant superantigenic and emetic activities. In addition, seq-harbouring S. aureus isolated from food poisoning outbreaks produced a large amount of SEQ, suggesting that seq-harbouring S. aureus could potentially be a hazard for food safety. SIGNIFICANCE AND IMPACT OF THE STUDY This study found, for the first time, that SEQ, a nonclassical SE, had remarkable stability to heat treatment and enzyme degradation and exhibited significant emetic activity, indicating that SEQ is a high-risk toxin in food poisoning.
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Affiliation(s)
- D-L Hu
- College of Veterinary Medicine, Jilin University, Changchun, Jiling, China.,Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.,Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - H K Ono
- Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.,Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - S Isayama
- Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan
| | - R Okada
- Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan
| | - M Okamura
- Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan
| | - L C Lei
- College of Veterinary Medicine, Jilin University, Changchun, Jiling, China
| | - Z S Liu
- College of Veterinary Medicine, Jilin University, Changchun, Jiling, China
| | - X-C Zhang
- College of Veterinary Medicine, Jilin University, Changchun, Jiling, China
| | - M Y Liu
- College of Veterinary Medicine, Jilin University, Changchun, Jiling, China
| | - J C Cui
- College of Life Science, Dalian Minzu University, Dalian, Liaoning, China
| | - A Nakane
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
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Benkerroum N. Staphylococcal enterotoxins and enterotoxin-like toxins with special reference to dairy products: An overview. Crit Rev Food Sci Nutr 2017; 58:1943-1970. [DOI: 10.1080/10408398.2017.1289149] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Noreddine Benkerroum
- Department of Food Science and Agricultural Chemistry, Macdonald-Stewart Building, McGill University, Macdonald Campus, Sainte-Anne-de-Bellevue, Canada
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Abstract
Staphylococcal enterotoxins (SEs) are unique bacterial toxins that cause gastrointestinal toxicity as well as superantigenic activity. Since systemic administration of SEs induces superantigenic activity leading to toxic shock syndrome that may mimic enterotoxic activity of SEs such as vomiting and diarrhea, oral administration of SEs in the monkey feeding assay is considered as a standard method to evaluate emetic activity of SEs. This chapter summarizes and discusses practical considerations of the monkey feeding assay used in studies characterizing classical and newly identified SEs.
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16
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Davey L, Halperin SA, Lee SF. Thiol-Disulfide Exchange in Gram-Positive Firmicutes. Trends Microbiol 2016; 24:902-915. [PMID: 27426970 DOI: 10.1016/j.tim.2016.06.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/08/2016] [Accepted: 06/28/2016] [Indexed: 11/17/2022]
Abstract
Extracytoplasmic thiol-disulfide oxidoreductases (TDORs) catalyze the oxidation, reduction, and isomerization of protein disulfide bonds. Although these processes have been characterized in Gram-negative bacteria, the majority of Gram-positive TDORs have only recently been discovered. Results from recent studies have revealed distinct trends in the types of TDOR used by different groups of Gram-positive bacteria, and in their biological functions. Actinobacteria TDORs can be essential for viability, while Firmicute TDORs influence various physiological processes, including protein stability, oxidative stress resistance, bacteriocin production, and virulence. In this review we discuss the diverse extracytoplasmic TDORs used by Gram-positive bacteria, with a focus on Gram-positive Firmicutes.
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Affiliation(s)
- Lauren Davey
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, B3H 1X5 Canada; Canadian Center for Vaccinology, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada
| | - Scott A Halperin
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, B3H 1X5 Canada; Canadian Center for Vaccinology, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada
| | - Song F Lee
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, B3H 1X5 Canada; Canadian Center for Vaccinology, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the IWK Health Centre, Halifax, NS, B3K 6R8 Canada; Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, Halifax, NS, B3H 4R2 Canada.
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Johler S, Sihto HM, Macori G, Stephan R. Sequence Variability in Staphylococcal Enterotoxin Genes seb, sec, and sed. Toxins (Basel) 2016; 8:toxins8060169. [PMID: 27258311 PMCID: PMC4926136 DOI: 10.3390/toxins8060169] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 11/16/2022] Open
Abstract
Ingestion of staphylococcal enterotoxins preformed by Staphylococcus aureus in food leads to staphylococcal food poisoning, the most prevalent foodborne intoxication worldwide. There are five major staphylococcal enterotoxins: SEA, SEB, SEC, SED, and SEE. While variants of these toxins have been described and were linked to specific hosts or levels or enterotoxin production, data on sequence variation is still limited. In this study, we aim to extend the knowledge on promoter and gene variants of the major enterotoxins SEB, SEC, and SED. To this end, we determined seb, sec, and sed promoter and gene sequences of a well-characterized set of enterotoxigenic Staphylococcus aureus strains originating from foodborne outbreaks, human infections, human nasal colonization, rabbits, and cattle. New nucleotide sequence variants were detected for all three enterotoxins and a novel amino acid sequence variant of SED was detected in a strain associated with human nasal colonization. While the seb promoter and gene sequences exhibited a high degree of variability, the sec and sed promoter and gene were more conserved. Interestingly, a truncated variant of sed was detected in all tested sed harboring rabbit strains. The generated data represents a further step towards improved understanding of strain-specific differences in enterotoxin expression and host-specific variation in enterotoxin sequences.
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Affiliation(s)
- Sophia Johler
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland.
| | - Henna-Maria Sihto
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland.
| | - Guerrino Macori
- National Reference Laboratory for Coagulase-Positive Staphylococci including Staphylococcus aureus, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
| | - Roger Stephan
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland.
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Stach CS, Schlievert PM. Lipopolysaccharide-Induced Toxic Shock Syndrome in Rabbits. Methods Mol Biol 2016; 1396:67-71. [PMID: 26676037 DOI: 10.1007/978-1-4939-3344-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Enhancement of susceptibility to lipopolysaccharide (LPS; endotoxin) is a defining characteristic of Staphylococcus aureus superantigens. At the time of this publication, there are 24 identified staphylococcal superantigens (SAgs), some of which have yet to be fully characterized. Testing the capacity of superantigens to potentiate LPS sensitivity is essential to characterize the role of these proteins in disease development. Here we describe how to perform studies of the enhancement of LPS-induced toxic shock syndrome in rabbits. This protocol also provides information on a second important activity of superantigens: the production of fever.
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Affiliation(s)
- Christopher S Stach
- Department of Microbiology, University of Iowa, 51 Newton Road, Bowen Science Building 3-403, Iowa City, IA, 52242, USA
| | - Patrick M Schlievert
- Department of Microbiology, University of Iowa, 51 Newton Road, Bowen Science Building 3-403, Iowa City, IA, 52242, USA.
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Identification and Characterization of a Novel Staphylococcal Emetic Toxin. Appl Environ Microbiol 2015; 81:7034-40. [PMID: 26231643 DOI: 10.1128/aem.01873-15] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 07/25/2015] [Indexed: 11/20/2022] Open
Abstract
Staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus have superantigenic and emetic activities, which cause toxic shock syndrome and staphylococcal food poisoning, respectively. Our previous study demonstrated that the sequence of SET has a low level of similarity to the sequences of other SEs and exhibits atypical bioactivities. Hence, we further explored whether there is an additional SET-related gene in S. aureus strains. One SET-like gene was found in the genome of S. aureus isolates that originated from a case of food poisoning, a human nasal swab, and a case of bovine mastitis. The deduced amino acid sequence of the SET-like gene showed 32% identity with the amino acid sequence of SET. The SET-like gene product was designated SElY. In the food poisoning and nasal swab isolates, mRNA encoding SElY was highly expressed in the early log phase of cultivation, whereas a high level of expression of this mRNA was found in the bovine mastitis isolate at the early stationary phase. To estimate whether SElY has both superantigenic and emetic activities, recombinant SElY was prepared. Cell proliferation and cytokine production were examined to assess the superantigenic activity of SElY. SElY exhibited superantigenic activity in human peripheral blood mononuclear cells but not in mouse splenocytes. In addition, SElY exhibited emetic activity in house musk shrews after intraperitoneal and oral administration. However, the stability of SElY against heating and pepsin and trypsin digestion was different from that of SET and SEA. From these results, we identified SElY to be a novel staphylococcal emetic toxin.
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20
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Stach CS, Herrera A, Schlievert PM. Staphylococcal superantigens interact with multiple host receptors to cause serious diseases. Immunol Res 2015; 59:177-81. [PMID: 24838262 DOI: 10.1007/s12026-014-8539-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Staphylococcus aureus strains that cause human diseases produce a large family of pyrogenic toxin superantigens (SAgs). These include toxic shock syndrome toxin-1 (TSST-1), the staphylococcal enterotoxins (SEs), and the SE-like proteins; to date, 23 staphylococcal SAgs have been described. Among the SAgs, three have been highly associated with human diseases (TSST-1, SEB, and SEC), likely because they are produced in high concentrations compared to other SAgs. Another major family of exotoxins produced by S. aureus is the cytolysins, particularly α-, β-, γ-, and δ-toxins, phenol soluble modulins, and leukocidins. This review discusses the association of SAgs with human diseases and particularly the "outside-in" signaling mechanism that leads to SAg-associated diseases. We discuss SAg interactions with three host immune cell receptors, including variable regions of the β-chain of the T cell receptor, MHC II α- and/or β-chains, and an epithelial/endothelial cell receptor that may include CD40. To a lesser extent, we discuss the role of cytolysins in facilitating disease production by SAgs.
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Affiliation(s)
- Christopher S Stach
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, IA, 52242, USA
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Sharma P, Wang N, Kranz DM. Soluble T cell receptor Vβ domains engineered for high-affinity binding to staphylococcal or streptococcal superantigens. Toxins (Basel) 2014; 6:556-74. [PMID: 24476714 PMCID: PMC3942751 DOI: 10.3390/toxins6020556] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus aureus and group A Streptococcus secrete a collection of toxins called superantigens (SAgs), so-called because they stimulate a large fraction of an individual’s T cells. One consequence of this hyperactivity is massive cytokine release leading to severe tissue inflammation and, in some cases, systemic organ failure and death. The molecular basis of action involves the binding of the SAg to both a T cell receptor (TCR) on a T cell and a class II product of the major histocompatibility complex (MHC) on an antigen presenting cell. This cross-linking leads to aggregation of the TCR complex and signaling. A common feature of SAgs is that they bind with relatively low affinity to the variable region (V) of the beta chain of the TCR. Despite this low affinity binding, SAgs are very potent, as each T cell requires only a small fraction of their receptors to be bound in order to trigger cytokine release. To develop high-affinity agents that could neutralize the activity of SAgs, and facilitate the development of detection assays, soluble forms of the Vβ regions have been engineered to affinities that are up to 3 million-fold higher for the SAg. Over the past decade, six different Vβ regions against SAgs from S. aureus (SEA, SEB, SEC3, TSST-1) or S. pyogenes (SpeA and SpeC) have been engineered for high-affinity using yeast display and directed evolution. Here we review the engineering of these high-affinity Vβ proteins, structural features of the six different SAgs and the Vβ proteins, and the specific properties of the engineered Vβ regions that confer high-affinity and specificity for their SAg ligands.
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Affiliation(s)
- Preeti Sharma
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
| | - Ningyan Wang
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
| | - David M Kranz
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
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Abstract
SUMMARY This review begins with a discussion of the large family of Staphylococcus aureus and beta-hemolytic streptococcal pyrogenic toxin T lymphocyte superantigens from structural and immunobiological perspectives. With this as background, the review then discusses the major known and possible human disease associations with superantigens, including associations with toxic shock syndromes, atopic dermatitis, pneumonia, infective endocarditis, and autoimmune sequelae to streptococcal illnesses. Finally, the review addresses current and possible novel strategies to prevent superantigen production and passive and active immunization strategies.
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24
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Assessment of the functional regions of the superantigen staphylococcal enterotoxin B. Toxins (Basel) 2013; 5:1859-71. [PMID: 24152989 PMCID: PMC3813916 DOI: 10.3390/toxins5101859] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 11/17/2022] Open
Abstract
The functional activity of superantigens is based on capacity of these microbial proteins to bind to both the β-chain of the T cell receptor (TcR) and the major histocompatibility complex (MHC) class II dimer. We have previously shown that a subset of the bacterial superantigens also binds to a membrane protein, designated p85, which is expressed by renal epithelial cells. This binding activity is a property of SEB, SEC1, 2 and 3, but not SEA, SED, SEE or TSST. The crystal structure of the tri-molecular complex of the superantigen staphylococcal enterotoxin B (SEB) with both the TcR and class II has previously been reported. However, the relative contributions of regions of the superantigen to the overall functional activity of this superantigen remain undefined. In an effort to better define the molecular basis for the interaction of SEB with the TcR β-chain, we report studies here which show the comparative contributions of amino- and carboxy-terminal regions in the superantigen activity of SEB. Recombinant fusion proteins composed of bacterial maltose-binding protein linked to either full-length or truncated toxins in which the 81 N-terminal, or 19 or 34 C-terminal amino acids were deleted, were generated for these studies. This approach provides a determination of the relative strength of the functional activity of the various regions of the superantigen protein.
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Maina EK, Hu DL, Asano K, Nakane A. Inhibition of emetic and superantigenic activities of staphylococcal enterotoxin A by synthetic peptides. Peptides 2012; 38:1-7. [PMID: 22955031 DOI: 10.1016/j.peptides.2012.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/17/2012] [Accepted: 08/17/2012] [Indexed: 11/25/2022]
Abstract
Staphylococcus aureus is a major human pathogen producing different types of toxins. Enterotoxin A (SEA) is the most common type among clinical and food-related strains. The aim of the present study was to estimate functional regions of SEA that are responsible for emetic and superantigenic activities using synthetic peptides. A series of 13 synthetic peptides corresponding to specific regions of SEA were synthesized, and the effect of these peptides on superantigenic activity of SEA including interferon γ (IFN-γ) production in mouse spleen cells, SEA-induced lethal shock in mice, spleen cell proliferation in house musk shrew, and emetic activity in shrews were assessed. Pre-treatment of spleen cells with synthetic peptides corresponding to the regions 21-40, 35-50, 81-100, or 161-180 of SEA significantly inhibited SEA-induced IFN-γ production and cell proliferation. These peptides also inhibited SEA-induced lethal shock. Interestingly, peptides corresponding to regions 21-40, 35-50 and 81-100 significantly inhibited SEA-induced emesis in house musk shrews, but region 161-180 did not. These findings indicated that regions 21-50 and 81-100 of SEA are important for both superantigenic and emetic activities of SEA molecule while region 161-180 is involved in superantigenic activity but not emetic activity of SEA. These regions could be important targets for therapeutic intervention against SEA exposure.
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Affiliation(s)
- Edward K Maina
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
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Xu SX, McCormick JK. Staphylococcal superantigens in colonization and disease. Front Cell Infect Microbiol 2012; 2:52. [PMID: 22919643 PMCID: PMC3417409 DOI: 10.3389/fcimb.2012.00052] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/29/2012] [Indexed: 12/28/2022] Open
Abstract
Superantigens (SAgs) are a family of potent immunostimulatory exotoxins known to be produced by only a few bacterial pathogens, including Staphylococcus aureus. More than 20 distinct SAgs have been characterized from different S. aureus strains and at least 80% of clinical strains harbor at least one SAg gene, although most strains encode many. SAgs have been classically associated with food poisoning and toxic shock syndrome (TSS), for which these toxins are the causative agent. TSS is a potentially fatal disease whereby SAg-mediated activation of T cells results in overproduction of cytokines and results in systemic inflammation and shock. Numerous studies have also shown a possible role for SAgs in other diseases such as Kawasaki disease (KD), atopic dermatitis (AD), and chronic rhinosinusitis (CRS). There is also now a rich understanding of the mechanisms of action of SAgs, as well as their structures and function. However, we have yet to discover what purpose SAgs play in the life cycle of S. aureus, and why such a wide array of these toxins exists. This review will focus on recent developments within the SAg field in terms of the molecular biology of these toxins and their role in both colonization and disease.
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Affiliation(s)
- Stacey X Xu
- Department of Microbiology and Immunology, Centre for Human Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London ON, Canada
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27
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DeGrasse JA. A single-stranded DNA aptamer that selectively binds to Staphylococcus aureus enterotoxin B. PLoS One 2012; 7:e33410. [PMID: 22438927 PMCID: PMC3306407 DOI: 10.1371/journal.pone.0033410] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/14/2012] [Indexed: 12/22/2022] Open
Abstract
The bacterium Staphylococcus aureus is a common foodborne pathogen capable of secreting a cocktail of small, stable, and strain-specific, staphylococcal enterotoxins (SEs). Staphylococcal food poisoning (SFP) results when improperly handled food contaminated with SEs is consumed. Gastrointestinal symptoms of SFP include emesis, diarrhea and severe abdominal pain, which manifest within hours of ingesting contaminated food. Immuno-affinity based methods directly detect, identify, and quantify several SEs within a food or clinical sample. However, the success of these assays depends upon the availability of a monoclonal antibody, the development of which is non-trivial and costly. The current scope of the available immuno-affinity based methods is limited to the classical SEs and does not encompass all of the known or emergent SEs. In contrast to antibodies, aptamers are short nucleic acids that exhibit high affinity and specificity for their targets without the high-costs and ethical concerns of animal husbandry. Further, researchers may choose to freely distribute aptamers and develop assays without the proprietary issues that increase the per-sample cost of immuno-affinity assays. This study describes a novel aptamer, selected in vitro, with affinity to staphylococcal enterotoxin B (SEB) that may be used in lieu of antibodies in SE detection assays. The aptamer, designated APT(SEB1), successfully isolates SEB from a complex mixture of SEs with extremely high discrimination. This work sets the foundation for future aptamer and assay development towards the entire family of SEs. The rapid, robust, and low-cost identification and quantification of all of the SEs in S. aureus contaminated food is essential for food safety and epidemiological efforts. An in vitro generated library of SE aptamers could potentially allow for the comprehensive and cost-effective analysis of food samples that immuno-affinity assays currently cannot provide.
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Affiliation(s)
- Jeffrey A DeGrasse
- Spectroscopy and Mass Spectrometry Branch, Division of Analytical Chemistry, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, College Park, Maryland, United States of America.
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Hennekinne JA, De Buyser ML, Dragacci S. Staphylococcus aureus and its food poisoning toxins: characterization and outbreak investigation. FEMS Microbiol Rev 2011; 36:815-36. [PMID: 22091892 DOI: 10.1111/j.1574-6976.2011.00311.x] [Citation(s) in RCA: 538] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 09/15/2011] [Accepted: 10/03/2011] [Indexed: 11/29/2022] Open
Abstract
Staphylococcal food poisoning (SFP) is one of the most common food-borne diseases and results from the ingestion of staphylococcal enterotoxins (SEs) preformed in food by enterotoxigenic strains of Staphylococcus aureus. To date, more than 20 SEs have been described: SEA to SElV. All of them have superantigenic activity whereas half of them have been proved to be emetic, representing a potential hazard for consumers. This review, divided into four parts, will focus on the following: (1) the worldwide story of SFP outbreaks, (2) the characteristics and behaviour of S. aureus in food environment, (3) the toxinogenic conditions and characteristics of SEs, and (4) SFP outbreaks including symptomatology, occurrence in the European Union and currently available methods used to characterize staphylococcal outbreaks.
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Affiliation(s)
- Jacques-Antoine Hennekinne
- French Agency for Food, Environmental and Occupational Health & Safety (Anses), Food Safety Laboratory of Maisons-Alfort, European Union Reference Laboratory for Coagulase Positive Staphylococci, Maisons-Alfort, France.
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Brosnahan AJ, Schlievert PM. Gram-positive bacterial superantigen outside-in signaling causes toxic shock syndrome. FEBS J 2011; 278:4649-67. [PMID: 21535475 DOI: 10.1111/j.1742-4658.2011.08151.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Staphylococcus aureus and Streptococcus pyogenes (group A streptococci) are Gram-positive pathogens capable of producing a variety of bacterial exotoxins known as superantigens. Superantigens interact with antigen-presenting cells (APCs) and T cells to induce T cell proliferation and massive cytokine production, which leads to fever, rash, capillary leak and subsequent hypotension, the major symptoms of toxic shock syndrome. Both S. aureus and group A streptococci colonize mucosal surfaces, including the anterior nares and vagina for S. aureus, and the oropharynx and less commonly the vagina for group A streptococci. However, due to their abilities to secrete a variety of virulence factors, the organisms can also cause illnesses from the mucosa. This review provides an updated discussion of the biochemical and structural features of one group of secreted virulence factors, the staphylococcal and group A streptococcal superantigens, and their abilities to cause toxic shock syndrome from a mucosal surface. The main focus of this review, however, is the abilities of superantigens to induce cytokines and chemokines from epithelial cells, which has been linked to a dodecapeptide region that is relatively conserved among all superantigens and is distinct from the binding sites required for interactions with APCs and T cells. This phenomenon, termed outside-in signaling, acts to recruit adaptive immune cells to the submucosa, where the superantigens can then interact with those cells to initiate the final cytokine cascades that lead to toxic shock syndrome.
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Affiliation(s)
- Amanda J Brosnahan
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, USA
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Li SJ, Hu DL, Maina E, Shinagawa K, Omoe K, Nakane A. Superantigenic activity of toxic shock syndrome toxin-1 is resistant to heating and digestive enzymes. J Appl Microbiol 2011; 110:729-36. [DOI: 10.1111/j.1365-2672.2010.04927.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Seitter M, Nerz C, Rosenstein R, Götz F, Hertel C. DNA microarray based detection of genes involved in safety and technologically relevant properties of food associated coagulase-negative staphylococci. Int J Food Microbiol 2011; 145:449-58. [PMID: 21329998 DOI: 10.1016/j.ijfoodmicro.2011.01.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 12/21/2010] [Accepted: 01/16/2011] [Indexed: 10/18/2022]
Abstract
Aim of the work was to design a polynucleotide based DNA microarray as screening tool to detect genes in food associated coagulase-negative staphylococci (CNS). A focus was laid on genes with potential health concern and technological relevance. The microarray contained 220 probes for genes encoding antibiotic resistances, hemolysins, toxins, amino acid decarboxylases (e.g. biogenic amine formation), binding proteins to extracellular matrix (ECM), lipases, proteases, stress response factors, or nitrate dissimilation. Hybridization of genomic DNA isolated from 32 phenotypically characterized CNS permitted to detect numerous genes, corresponding with the phenotype. However, numerous hybridization signals were obtained for genes without any detectable phenotype. The antibiotic resistance genes blaZ, lnuA, and tetK involved in ß-lactam, lincomycin and tetracycline resistance, respectively, were rarely identified in CNS, however, all species contained some strains with such resistance genes. Decarboxylase genes involved in biogenic amine formation were detected regularly in Staphylococcus carnosus, S. condimenti, S. piscifermentans and S. equorum, but was rarely correlated with the phenotype. The same applied for the fibrinogen (clf) and fibronectin (fbp) binding protein genes, whose phenotype (binding assay) was only correlated in S. equorum and Staphylococcus succinus. Although some CNS showed hemolytic activity and enterotoxin production (Immunoblot) the corresponding genes could not be verified. Technological relevant genes such as proteases or lipases revealed good hybridization signals. In addition, genes involved in nitrate dissimilation (nre, nar, nir), catalase (kat), or superoxide dismutase (sod) were well detected. Interestingly, genes involved in dissimilatory nitrate reduction were more prevalent in strains of S. carnosus, S. condimenti and S. piscifermentans than of S. equorum, S. succinus and S. xylosus.
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Affiliation(s)
- Marion Seitter
- University of Hohenheim, Institute of Food Science and Biotechnology, Section Food Microbiology, Garbenstrasse 28, D-70599 Stuttgart, Germany
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Li SJ, Hu DL, Maina E, Shinagawa K, Omoe K, Nakane A. Superantigenic activity of toxic shock syndrome toxin-1 is resistant to heating and digestive enzymes. J Appl Microbiol 2011. [DOI: 10.1111/j.1365-2672.2011.04927.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Multiple roles of Staphylococcus aureus enterotoxins: pathogenicity, superantigenic activity, and correlation to antibiotic resistance. Toxins (Basel) 2010; 2:2117-31. [PMID: 22069676 PMCID: PMC3153285 DOI: 10.3390/toxins2082117] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Accepted: 08/09/2010] [Indexed: 12/03/2022] Open
Abstract
Heat-stable enterotoxins are the most notable virulence factors associated with Staphylococcus aureus, a common pathogen associated with serious community and hospital acquired diseases. Staphylococcal enterotoxins (SEs) cause toxic shock-like syndromes and have been implicated in food poisoning. But SEs also act as superantigens that stimulate T-cell proliferation, and a high correlation between these activities has been detected. Most of the nosocomial S. aureus infections are caused by methicillin-resistant S. aureus (MRSA) strains, and those resistant to quinolones or multiresistant to other antibiotics are emerging, leaving a limited choice for their control. This review focuses on these diverse roles of SE, their possible correlations and the influence in disease progression and therapy.
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Argudín MÁ, Mendoza MC, Rodicio MR. Food poisoning and Staphylococcus aureus enterotoxins. Toxins (Basel) 2010; 2:1751-73. [PMID: 22069659 PMCID: PMC3153270 DOI: 10.3390/toxins2071751] [Citation(s) in RCA: 617] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 06/24/2010] [Accepted: 06/30/2010] [Indexed: 01/31/2023] Open
Abstract
Staphylococcus aureus produces a wide variety of toxins including staphylococcal enterotoxins (SEs; SEA to SEE, SEG to SEI, SER to SET) with demonstrated emetic activity, and staphylococcal-like (SEl) proteins, which are not emetic in a primate model (SElL and SElQ) or have yet to be tested (SElJ, SElK, SElM to SElP, SElU, SElU2 and SElV). SEs and SEls have been traditionally subdivided into classical (SEA to SEE) and new (SEG to SElU2) types. All possess superantigenic activity and are encoded by accessory genetic elements, including plasmids, prophages, pathogenicity islands, vSa genomic islands, or by genes located next to the staphylococcal cassette chromosome (SCC) implicated in methicillin resistance. SEs are a major cause of food poisoning, which typically occurs after ingestion of different foods, particularly processed meat and dairy products, contaminated with S. aureus by improper handling and subsequent storage at elevated temperatures. Symptoms are of rapid onset and include nausea and violent vomiting, with or without diarrhea. The illness is usually self-limiting and only occasionally it is severe enough to warrant hospitalization. SEA is the most common cause of staphylococcal food poisoning worldwide, but the involvement of other classical SEs has been also demonstrated. Of the new SE/SEls, only SEH have clearly been associated with food poisoning. However, genes encoding novel SEs as well as SEls with untested emetic activity are widely represented in S. aureus, and their role in pathogenesis may be underestimated.
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Affiliation(s)
- María Ángeles Argudín
- Department of Functional Biology (Section of Microbiology) and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain.
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Schlievert PM, Strandberg KL, Lin YC, Peterson ML, Leung DYM. Secreted virulence factor comparison between methicillin-resistant and methicillin-sensitive Staphylococcus aureus, and its relevance to atopic dermatitis. J Allergy Clin Immunol 2010; 125:39-49. [PMID: 20109735 DOI: 10.1016/j.jaci.2009.10.039] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/23/2009] [Accepted: 10/26/2009] [Indexed: 12/21/2022]
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains have emerged as serious health threats in the last 15 years. They are associated with large numbers of atopic dermatitis skin and soft tissue infections, but when they originate from skin and mucous membranes, have the capacity to produce sepsis and highly fatal pulmonary infections characterized as necrotizing pneumonia, purpura fulminans, and postviral toxic shock syndrome. This review is a discussion of the emergence of 3 major CA-MRSA organisms, designated CA-MRSA USA400, followed by USA300, and most recently USA200. CA-MRSA USA300 and USA400 isolates and their methicillin-sensitive counterparts (community-associated methicillin-sensitive S aureus) typically produce highly inflammatory cytolysins alpha-toxin, gamma-toxin, delta-toxin (as representative of the phenol soluble modulin family of cytolysins), and Panton Valentine leukocidin. USA300 isolates produce the superantigens enterotoxin-like Q and a highly pyrogenic deletion variant of toxic shock syndrome toxin 1 (TSST-1), whereas USA400 isolates produce the superantigens staphylococcal enterotoxin B or staphylococcal enterotoxin C. USA200 CA-MRSA isolates produce small amounts of cytolysins but produce high levels of TSST-1. In contrast, their methicillin-sensitive S aureus counterparts produce various cytolysins, apparently in part dependent on the niche occupied in the host and levels of TSST-1 expressed. Significant differences seen in production of secreted virulence factors by CA-MRSA versus hospital-associated methicillin-resistant S aureus and community-associated methicillin-sensitive S aureus strains appear to be a result of the need to specialize as the result of energy drains from both virulence factor production and methicillin resistance.
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Affiliation(s)
- Patrick M Schlievert
- Department of Microbiology, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
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Functional analysis of the disulphide loop mutant of staphylococcal enterotoxin C2. Appl Microbiol Biotechnol 2009; 82:861-71. [DOI: 10.1007/s00253-008-1800-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 11/17/2008] [Accepted: 11/17/2008] [Indexed: 10/21/2022]
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37
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Norgren M, Eriksson A. Streptococcal Superantigens and Their Role in the Pathogenesis of Severe Infections. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569549709064091] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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38
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Staphylococcus aureus enterotoxin C2 mutants: biological activity assay in vitro. J Ind Microbiol Biotechnol 2008; 35:975-80. [PMID: 18506495 DOI: 10.1007/s10295-008-0372-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 05/12/2008] [Indexed: 10/22/2022]
Abstract
Staphylococcal enterotoxin C2 (SEC2) is one member of bacterial superantigens produced by Staphylococcus aureus. It can be attributed to its superantigenic activity to cross-link major histocompatibility complex class II molecules with T-cell receptors and activate a large number of resting T cells resulting in release of massive cytokines, which will produce significant tumor inhibition in vivo and in vitro. However, it could be not broadly applied to cure malignant tumors in clinic because of emetic activity of SEC2. The aim of this study was to inactivate emetic activity of SEC2 through site-directed mutagenesis. Cys93, Cys110 and His118 were selected as substitutional sites based on the functional sites responsible for emesis. The mutated proteins were used to determine Peripheral blood mononuclear cell proliferation activity and anti-tumor activity in vitro. Results showed that these mutated proteins efficiently stimulated T cell and exhibited the same tumor-inhibition effect as SEC2. It is possible to inactivate emetic activity of SEC2 through site-directed mutagenesis and provide satisfying agents for tumor treatment in clinic.
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Heras B, Kurz M, Jarrott R, Shouldice SR, Frei P, Robin G, Čemažar M, Thöny-Meyer L, Glockshuber R, Martin JL. Staphylococcus aureus DsbA Does Not Have a Destabilizing Disulfide. J Biol Chem 2008; 283:4261-71. [DOI: 10.1074/jbc.m707838200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Seo KS, Lee SU, Park YH, Davis WC, Fox LK, Bohach GA. Long-term staphylococcal enterotoxin C1 exposure induces soluble factor-mediated immunosuppression by bovine CD4+ and CD8+ T cells. Infect Immun 2006; 75:260-9. [PMID: 17030573 PMCID: PMC1828382 DOI: 10.1128/iai.01358-06] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Regulatory T cells (T(regs)) help control the development and maintenance of protective immunity and can lead to aberrant immune responses to some pathogens. Several lines of evidence suggest that T(regs) are induced by exposure to superantigens (SAgs) in vitro or in vivo. In this study, bovine peripheral blood mononuclear cells (PBMC) were exposed in vitro to a relatively low dose (5 ng/ml) of staphylococcal enterotoxin C1 (SEC1) for up to 10 days. Upon stimulation, CD4+ and CD8+ T cells initially proliferated at similar rates. Subsequently, from days 6 through 10, most CD4+ and CD8+ T cells proliferated regardless of Vbeta specificity, but the proliferation of CD8+ T cells occurred more vigorously. The transcription of CD25 and CD152 genes increased, whereas that of interleukin-2 (IL-2) decreased. gammadelta T cells appeared to be unresponsive. An increase in the transcription of IL-10 and transforming growth factor beta (TGF-beta) genes in SEC1-stimulated cultures was attributed to the CD4+ CD25+ T-cell subpopulation. The expression of Foxp3 mRNA also increased and was accompanied by the upregulation of CD152 and the downregulation of IL-2 transcription, suggesting that cells in this subpopulation are T(regs). Functionally, SEC1-stimulated CD4+ T cells suppressed the proliferation of naive PBMC in response to heat-killed-fixed Staphylococcus aureus. The suppression was partially mediated by IL-10 and TGF-beta, another characteristic of certain types of T(regs.) The CD8+ T-cell population also suppressed naive PBMC through another mechanism not mediated by IL-10 or TGF-beta. These results provide further insight into the potential mechanisms by which SAgs could contribute to evasion of the immune response, affecting the outcome of infection or colonization.
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Affiliation(s)
- Keun Seok Seo
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, South Line Street, Agricultural Biotechnology Building 222, Moscow, ID 83844, USA
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41
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Dumoulin A, Grauschopf U, Bischoff M, Thöny-Meyer L, Berger-Bächi B. Staphylococcus aureus DsbA is a membrane-bound lipoprotein with thiol-disulfide oxidoreductase activity. Arch Microbiol 2005; 184:117-28. [PMID: 16177891 DOI: 10.1007/s00203-005-0024-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 06/08/2005] [Accepted: 06/22/2005] [Indexed: 02/03/2023]
Abstract
DsbA proteins, the primary catalysts of protein disulfide bond formation, are known to affect virulence and penicillin resistance in Gram-negative bacteria. We identified a putative DsbA homologue in the Gram-positive pathogen Staphylococcus aureus that was able to restore the motility phenotype of an Escherichia coli dsbA mutant and thus demonstrated a functional thiol oxidoreductase activity. The staphylococcal DsbA (SaDsbA) had a strong oxidative redox potential of -131 mV. The persistence of the protein throughout the growth cycle despite its predominant transcription during exponential growth phase suggested a rather long half-life for the SaDsbA. SaDsbA was found to be a membrane localised lipoprotein, supporting a role in disulfide bond formation. But so far, neither in vitro nor in vivo phenotype could be identified in a staphylococcal dsbA mutant, leaving its physiological role unknown. The inability of SaDsbA to interact with the E. coli DsbB and the lack of an apparent staphylococcal DsbB homologue suggest an alternative re-oxidation pathway for the SaDsbA.
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Affiliation(s)
- Alexis Dumoulin
- Department of Medical Microbiology, University of Zürich, Gloriastr 32, 8006 Zürich, Switzerland
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42
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Kwon NH, Kim SH, Park KT, Bae WK, Kim JY, Lim JY, Ahn JS, Lyoo KS, Kim JM, Jung WK, Noh KM, Bohach GA, Park YH. Application of extended single-reaction multiplex polymerase chain reaction for toxin typing of Staphylococcus aureus isolates in South Korea. Int J Food Microbiol 2005; 97:137-45. [PMID: 15541800 DOI: 10.1016/j.ijfoodmicro.2004.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2003] [Revised: 03/31/2004] [Accepted: 04/22/2004] [Indexed: 10/26/2022]
Abstract
The extended single-reaction multiplex PCR (esr-mPCR) developed in this study to detect staphylococcal enterotoxins (SEs), including SEA, SEB, SEC, SED, SEE, SEH, SEI, and SEJ, requires fewer sets of primers than other conventional multiplex PCRs and can be used to detect newly identified staphylococcal enterotoxins SEs more readily. Esr-mPCR analysis of 141 isolates of Staphylococcus aureus obtained from abattoir and livestock product samples revealed that 27 of the S. aureus isolates were toxigenic, and two were 2 multitoxigenic isolates. The most prevalent SE type was SEI followed by SEA and SEH. In addition, we investigated the clonal relatedness of toxigenic S. aureus isolates by arbitrarily primed PCR (AP-PCR). AP-PCR analysis of toxigenic S. aureus isolates revealed that the discriminatory power of AP-PCR was 9 (D=0.81), 8 (D=0.77), and 10 types (D=0.83) with primers AP1, ERIC2, and AP7, respectively. The combination of three each AP-PCR result could rearrange toxigenic S. aureus isolates into 10 types and five subtypes, with the D-value of 0.92. Interestingly, our data showed that toxigenic S. aureus isolates from different sources had different fingerprinting patterns although some of them carried the same types of SE genes. These data suggest that combinations of esr-mPCR and AP-PCR can provide a powerful approach for epidemiological investigation of toxigenic S. aureus isolates.
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Affiliation(s)
- N H Kwon
- Department of Microbiology, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, Shilim 9-dong, Gwanak-gu, Seoul 151-742, Republic of Korea
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43
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Abstract
Superantigens are a class of highly potent immuno-stimulatory molecules produced by Staphylococcus aureus and Streptococcus pyogenes. These toxins possess the unique ability to interact simultaneously with MHC class II molecules and T-cell receptors, forming a trimolecular complex that induces profound T-cell proliferation. The resultant massive cytokine release causes epithelial damage and leads to capillary leak and hypotension. The staphylococcal superantigens are designated staphylococcal enterotoxins A, B, C (and antigenic variants), D, E, and the recently discovered enterotoxins G to Q, and toxic shock syndrome toxin-1. The streptococcal superantigens include the pyrogenic exotoxins A (and antigenic variants), C, G-J, SMEZ, and SSA. Superantigens are implicated in several diseases including toxic shock syndrome, scarlet fever and food poisoning; and their function appears primarily to debilitate the host sufficiently to permit the causation of disease. Structural studies over the last 10 years have provided a great deal of information regarding the complex interactions of these molecules with their receptors. This, combined with the wealth of new information from genomics initiatives, have shown that, despite their common molecular architecture, superantigens are able to crosslink MHC class II molecules and T-cell receptors by a variety of subtly different ways through the use of various structural regions within each toxin.
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Affiliation(s)
- Matthew D Baker
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
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Orwin PM, Fitzgerald JR, Leung DYM, Gutierrez JA, Bohach GA, Schlievert PM. Characterization of Staphylococcus aureus enterotoxin L. Infect Immun 2003; 71:2916-9. [PMID: 12704169 PMCID: PMC153286 DOI: 10.1128/iai.71.5.2916-2919.2003] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus causes a wide variety of diseases. Major virulence factors of this organism include enterotoxins (SEs) that cause both food poisoning and toxic shock syndrome. Recently, a novel SE, tentatively designated SEL, was identified in a pathogenicity island from a bovine mastitis isolate. The toxin had a molecular weight of 26,000 and an isoelectric point of 8.5. Recombinant SEL shared many biological activities with SEs, including superantigenicity, pyrogenicity, enhancement of endotoxin shock, and lethality in rabbits when administered in subcutaneous miniosmotic pumps, but the protein lacked emetic activity. T cells bearing the T-cell receptor beta chain variable regions 5.1, 5.2, 6.7, 16, and 22 were significantly stimulated by recombinant SEL.
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Affiliation(s)
- Paul M Orwin
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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45
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Chi YI, Sadler I, Jablonski LM, Callantine SD, Deobald CF, Stauffacher CV, Bohach GA. Zinc-mediated dimerization and its effect on activity and conformation of staphylococcal enterotoxin type C. J Biol Chem 2002; 277:22839-46. [PMID: 11934896 DOI: 10.1074/jbc.m201932200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Staphylococcal enterotoxins are superantigen exotoxins that mediate food poisoning and toxic shock syndrome in humans. Despite their structural and functional similarities, superantigens display subtle differences in biological properties and modes of receptor binding as a result of zinc atoms bound differently in their crystal structures. For example, the crystal structures of the staphylococcal enterotoxins in the type C serogroup (SECs) contain a zinc atom coordinated by one aspartate and two histidine residues from one molecule and another aspartate residue from the next molecule, thus forming a dimer. This type of zinc ligation and zinc-mediated dimerization occurs in several SECs, but not in most other staphylococcal enterotoxin serogroups. This prompted us to investigate the potential importance of zinc in SEC-mediated pathogenesis. Site-directed mutagenesis was used to replace SEC zinc binding ligands with alanine. SEC mutants unable to bind zinc did not have major conformational alterations although they failed to form dimers. Zinc binding was not essential for T cell stimulation, emesis, or lethality although in general the mutants were less pyrogenic. Thus the zinc atom in SECs might represent a non-functional heavy atom in an exotoxin group that has diverged from related bacterial toxins containing crucial zinc atoms.
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Affiliation(s)
- Young-In Chi
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
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46
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Yarwood JM, McCormick JK, Paustian ML, Orwin PM, Kapur V, Schlievert PM. Characterization and expression analysis of Staphylococcus aureus pathogenicity island 3. Implications for the evolution of staphylococcal pathogenicity islands. J Biol Chem 2002; 277:13138-47. [PMID: 11821418 DOI: 10.1074/jbc.m111661200] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
We describe the complete sequence of the 15.9-kb staphylococcal pathogenicity island 3 encoding staphylococcal enterotoxin serotypes B, K, and Q. The island, which meets the generally accepted definition of pathogenicity islands, contains 24 open reading frames potentially encoding proteins of more than 50 amino acids, including an apparently functional integrase. The element is bordered by two 17-bp direct repeats identical to those found flanking staphylococcal pathogenicity island 1. The island has extensive regions of homology to previously described pathogenicity islands, particularly staphylococcal pathogenicity islands 1 and bov. The expression of 22 of the 24 open reading frames contained on staphylococcal pathogenicity island 3 was detected either in vitro during growth in a laboratory medium or serum or in vivo in a rabbit model of toxic shock syndrome using DNA microarrays. The effect of oxygen tension on staphylococcal pathogenicity island 3 gene expression was also examined. By comparison with the known staphylococcal pathogenicity islands in the context of gene expression described here, we propose a model of pathogenicity island origin and evolution involving specialized transduction events and addition, deletion, or recombination of pathogenicity island "modules."
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Affiliation(s)
- Jeremy M Yarwood
- Department of Microbiology, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN 55455, USA
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47
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Orwin PM, Leung DY, Donahue HL, Novick RP, Schlievert PM. Biochemical and biological properties of Staphylococcal enterotoxin K. Infect Immun 2001; 69:360-6. [PMID: 11119525 PMCID: PMC97891 DOI: 10.1128/iai.69.1.360-366.2001] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is an important human pathogen which is implicated in a wide variety of diseases. Major determinants of the virulence of this organism include extracellular virulence factors. Staphylococcal enterotoxins (SEs) are important causative agents in staphylococcal toxic shock syndrome and food poisoning. Our study identified a novel enterotoxin, SEK, and examined its biochemical and biological properties. SEK had a molecular weight of 26,000 and an experimentally determined pI of between 7.0 and 7.5. SEK was secreted by clinical isolates of S. aureus. We demonstrated that SEK had many of the biological activities associated with the SEs, including superantigenicity, pyrogenicity, the ability to enhance the lethal effect of endotoxin, and lethality in a rabbit model when administered by subcutaneous miniosmotic pump. Recombinant SEK was shown to stimulate human CD4(+) and CD8(+) T cells in a Vbeta-specific manner; T-cells bearing Vbeta 5.1, 5.2, and 6.7 were significantly stimulated to proliferate.
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Affiliation(s)
- P M Orwin
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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48
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Dziewanowska K, Carson AR, Patti JM, Deobald CF, Bayles KW, Bohach GA. Staphylococcal fibronectin binding protein interacts with heat shock protein 60 and integrins: role in internalization by epithelial cells. Infect Immun 2000; 68:6321-8. [PMID: 11035741 PMCID: PMC97715 DOI: 10.1128/iai.68.11.6321-6328.2000] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We reported previously that internalization of Staphylococcus aureus by nonprofessional phagocytes involves an interaction between fibronectin (Fn) binding protein (FnBP) and the host cell, resulting in signal transduction, tyrosine kinase activity, and cytoskeletal rearrangement (K. Dziewanowska, J. M. Patti, C. F. Deobald, K. W. Bayles, W. R. Trumble, and G. A. Bohach, Infect. Immun. 67:4673-4678, 1999). The goal of the present study was to identify the host molecules responsible for uptake of the organism through an interaction with FnBP. First, Fn was required for internalization. Addition of small amounts of exogenous Fn stimulated the uptake of S. aureus by HEp-2 cells, which are deficient in Fn synthesis. Fn antibodies blocked internalization of the organism by MAC-T cell monolayers, a bovine epithelial cell line which expresses Fn. Second, a monoclonal antibody (MAb) specific for beta(1) integrins dramatically reduced S. aureus invasion, suggesting that the formation of a Fn bridge linking the host cell beta(1) integrin and FnBP precedes internalization. However, ligand blotting of cell membrane proteins with a functional fragment of FnBP consistently identified an additional approximately 55-kDa receptor on both human and bovine epithelial cells. This protein was purified and identified by N-terminal microsequencing as heat shock protein 60 (Hsp60). The interaction between FnBP and Hsp60 also occurred when the whole cells were used. Cell membrane localization of Hsp60 was confirmed by biotinylation with an agent nonpermeable to the cell membrane. Pretreatment of epithelial cells with a MAb specific for eukaryotic Hsp60 significantly reduced internalization of S. aureus. Combined, these results suggest that the FnBP binds directly to both Hsp60 and Fn and is linked to beta(1) integrins through a Fn bridge. The simultaneous involvement of Fn and two host cell ligands, beta(1) integrins and Hsp60, suggests that FnBP is a multifunctional adhesin that mediates internalization in a manner similar to that proposed for OpaA, the Neisseria gonorrhoeae FnBP homolog (J. P. M. van Putten, T. D. Duensing, and R. L. Cole, Mol. Microbiol. 29:369-379, 1998).
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Affiliation(s)
- K Dziewanowska
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844, USA
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49
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Abstract
Superantigens are highly potent immune stimulators with a unique ability to interact simultaneously with MHC class II molecules and T cell receptors, forming a trimolecular complex that induces profound T-cell proliferation and massive cytokine production. Recent structural studies have provided a wealth of information regarding these complex interactions, and it is now emerging that, despite their common 3-D architecture, superantigens are able to crosslink MHC class II molecules and T cell receptors in a variety of ways.
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Affiliation(s)
- A C Papageorgiou
- are in the Dept of Biology and Biochemistry, University of Bath, Claverton Down, Bath, UK BA2 7AY
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50
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Abstract
This article reviews the literature regarding the structure and function of two types of exotoxins expressed by Staphylococcus aureus, pyrogenic toxin superantigens (PTSAgs) and hemolysins. The molecular basis of PTSAg toxicity is presented in the context of two diseases known to be caused by these exotoxins: toxic shock syndrome and staphylococcal food poisoning. The family of staphylococcal PTSAgs presently includes toxic shock syndrome toxin-1 (TSST-1) and most of the staphylococcal enterotoxins (SEs) (SEA, SEB, SEC, SED, SEE, SEG, and SEH). As the name implies, the PTSAgs are multifunctional proteins that invariably exhibit lethal activity, pyrogenicity, superantigenicity, and the capacity to induce lethal hypersensitivity to endotoxin. Other properties exhibited by one or more staphylococcal PTSAgs include emetic activity (SEs) and penetration across mucosal barriers (TSST-1). A detailed review of the molecular mechanisms underlying the toxicity of the staphylococcal hemolysins is also presented.
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