Perfil del riesgo de brotes alimentarios por intoxicación estafilocócica en Cuba / Risk profile of staphylococcal food poisoning outbreaks in Cuba

Introducción: Staphylococcus ocasiona con frecuencia intoxicaciones alimentarias; en Cuba es una de las principales causas de brotes. Objetivo: analizar el perfil del riesgo de brotes alimentarios por Staphylococcus en Cuba. Métodos: Se realizó un estudio observacional analítico sobre los factores higiénicos y epidemiológicos asociados al riesgo de la intoxicación alimentaria por Staphylococcus en Cuba, en el Instituto Nacional de Higiene Epidemiología y Microbiología, durante el periodo de enero a noviembre de 2018. La información se obtuvo mediante revisión bibliográfica sistémica, análisis de datos del Laboratorio de Referencia Nacional en Microbiología Sanitaria y informes de brotes de la Dirección Nacional de Salud Ambiental. Se estimó el riesgo microbiológico mediante el programa semicuantitativo Ross-Sumner. Resultados: Se identificó como principal peligro Stahylococcus aureus, productores de enterotoxina A y la determinación de aislamientos resistentes a los antimicrobianos, como Stahylococcus aureus meticilina resistentes. Los alimentos más implicados fueron los productos de repostería y la inocuidad se afectó en mayor frecuencia por la contaminación cruzada en el 31,4 por ciento brotes y la inadecuada conservación en 46,1 por ciento. La predicción de personas que enferman por año en la población de interés fue de 6 260. Conclusiones: El riesgo de la ocurrencia de brotes por Staphylococcus se estimó como alto; la vigilancia se recomienda en alimentos que requieren manipulación directa y no se aplica tratamiento térmico antes del consumo, con gestiones de riesgo dirigidas a productores y consumidores(AU)

Introduction: Staphylococcus is a frequent cause of food poisoning. In Cuba it is one of the main causes of outbreaks. Objective: Analyze the risk profile of staphylococcal food poisoning outbreaks in Cuba. Methods: An observational analytical study was conducted about hygienic and epidemiological factors associated to the risk for staphylococcal food poisoning in Cuba. The study was carried out at the National Institute of Hygiene, Epidemiology and Microbiology from January to November 2018. The information was obtained from a systematic bibliographic review, analysis of data from the Medical Microbiology National Reference Laboratory, and outbreak reports from the National Environmental Health Division. Microbiological risk was estimated with Ross-Sumner semi-quantitative software. Results: The main hazard identified was Staphylococcus aureus, enterotoxin A producers and determination of antimicrobial resistant isolates like methicillin-resistant Staphylococcus aureus. The food items most commonly involved were sweets, and safety was most frequently affected by cross-contamination in 31.4 percent of the outbreaks and inadequate preservation in 46.1 percent. Prediction of members of the population of interest becoming ill every year was 6 260. Conclusions: Risk for the occurrence of staphylococcal food poisoning outbreaks was considered to be high; surveillance is recommended of food items requiring direct manipulation and appropriate thermal treatment is not applied before consumption, with risk management actions aimed at manufacturers and consumers(AU)

Frequency of Staphylococcus aureus virulence genes in milk of cows and goats with mastitis / Frequência de genes fatores de virulência de Staphylococcus aureus em leite de vacas e cabras com mastite

The present study determined the frequency of Staphylococcus aureus virulence genes in 2,253 milk samples of cows (n=1000) and goats (n=1253) raised in three different geographical regions of the state Pernambuco, Brazil. The presence of genes of virulence factors associated to adhesion to host cells (fnbA, fnbB, clfA and clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla and hlb), and capsular polysaccharide (cap5 and cap8) was evaluated by PCR. A total of 123 and 27 S. aureus strains were isolated from cows' and goats' milk, respectively. The sec and tsst genes were detected exclusively in goats' isolates, while the seh gene was only identified in cows' isolates. The number of toxin genes per strain showed that goats' isolates are likely more toxic than bovines' isolates. The cap5 genotype predominated in both host species, especially in strains collected from cows raised in the Agreste region. The cap8 genotype is likely more virulent due to the number of virulence genes per strain. The results of the present study demonstrate that S. aureus may pose a potential threat to human health in Brazil, and, therefore, these results should support actions related to mastitis control programs.(AU)

O presente estudo determinou a frequência de genes de virulência de Staphylococcus aureus em 2253 amostras de leite, sendo de vacas n=1000 e de cabras n=1253, procedentes das três regiões geográficas do estado de Pernambuco, Brasil. A presença de genes de fatores de virulência associados à adesão às células hospedeiras (fnbA, fnbB, clfA e clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla e hlb) e polissacarídeo capsular (cap5 e cap8) foram avaliadas por PCR. Um total de 123 e 27 cepas de S. aureus foram isoladas do leite de vacas e cabras, respectivamente. Os genes sec e tsst foram detectados exclusivamente em isolados de cabras, enquanto o gene seh foi identificado apenas em isolados de vaca. O número de genes de toxina por cepa mostrou que os isolados de cabras são potencialmente mais tóxicos do que os isolados obtidos de bovinos. O genótipo cap5 predominou em ambas as espécies hospedeiras, especialmente em cepas coletadas de vacas criadas na região Agreste. O genótipo cap8 é potencialmente mais virulento devido ao número de genes de virulência por isolado. Os resultados do presente estudo demonstram que S. aureus pode representar uma ameaça potencial para a saúde humana no Brasil e, portanto, estes resultados devem subsidiar ações relacionadas aos programas de controle de mastite.(AU)

Establishment of a mouse model of IgA nephropathy induced by superantigen staphylococcal enterotoxin B / 中国比较医学杂志

Objective To establish a mouse model of IgA nephropathy and to observe its biochemical and pathological characteristics. Methods Twelve BALB/c mice were randomly divided into the normal group and model group, with 6 mice in each group. Mice in the model group received an intravenous injection of 0. 8 mg/kg superantigen staphylococcal enterotoxin B (SEB) into the tail vein once a week for three weeks. At the end of the 4th week, the mice were sacrificed, and the 24 h-urinary protein, urinary microalbumin, the renal function indicators BUN, Scr and UA were measured, levels of liver function indicators ALT, AST, ALP, and the blood lipid levels of TC, TG, and LDL were determined, the renal morphological changes were examined by pathology using HE, PAS, PASM and Masson staining, and by electron microscopy, the IgA deposition in the renal tissue was observed with immunofluorescence, and the liver and small intestine were observed by pathology using HE staining. Results Compared with the normal group, the mice of model group showed increased 24-hour urinary protein and urinary microalbumin (P<0. 01), increased CREA and UA (P<0. 05), but not significantly changed BUN, TP and ALB. The liver function indicator AST was significantly increased (P<0. 05), but ALT and ALP were not significantly changed. The blood lipid TG was significantly decreased (P<0. 05) and LDL increased (P<0. 01), while the TC was not significantly changed. The kidney tissues had moderate histological changes, and immunofluorescence observation showed granular or massive IgA deposition in the renal glomerular mesangium. The liver tissue had some inflammatory cell infiltration and hepatocyte necrosis. The small intestine showed slender and shortened villi with widened inter-villous space and sloughed off epithelial cells, dilated central lacteal, and lymphocyte infiltration. Conclusions A mouse model of IgA nephropathy can be successfully established by tail vein injection of superantigen staphylococcal entrotoxin B.

Study on design and three-dimension structure of a broad-spectrum inhibitory peptide against staphylococcal enterotoxins superantigen / 中国免疫学杂志

Objective:Peptides were designed on the basis of high conservative regions of amino acid sequences and structures of the SEs,three-dimension structure of P72 was constructed.Methods: Bioinformatics analysis softwares such as Vector NTI 10.3, InsightII 2000,Discovery Studio 1.7 were used to analyse and predict the space structure of P72.Results:three-dimensional domains of the peptide P72 from SEA, SEB and SEC were quite similar, Peptide P72 was far away from TCRVβchain and MHC class II molecule.Conclusion:The inhibitory activity of peptide P72 may not due to binding to MHCⅡ and TCRVβchain.The exact mechanism of inhibitory activity of P72 should be explored.

Association Between PTPN22 Polymorphisms and IgE Responses to Staphylococcal Superantigens in Chronic Urticaria

Protein tyrosine phosphatase-22 (PTPN22) gene encodes lymphoid-specific tyrosine phosphatase (Lyp), an inhibitor of T cell activation. A polymorphism of the PTPN22 gene has been found to be associated with chronic urticaria (CU). We investigated the associations between PTPN22 gene polymorphisms and CU characteristics, including serum specific IgE antibodies response to toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin A (SEA). CU patients (n=409) and normal healthy controls (n=388) were enrolled in the present study. Serum specific IgE to TSST-1 and SEA were measured by ImmunoCAP(R). Five PTPN22 single nucleotide polymorphisms, -1123G>C, 1858C>T, 13145A>G, 14943C>T, and 20628A>G, were genotyped. There were no significant differences in genotype or haplotype frequencies of these polymorphisms between the 2 groups. CU patients carrying the GG genotype at 20628A>G (P=0.035) or haplotype 3 [GGG] (P=0.047) had a significantly higher prevalence of serum specific IgE to TSST-1 compared to non-carriers. Similarly, CT/TT genotype at 14943C>T had a significantly higher prevalence of serum specific IgE to SEA (P=0.045). The findings suggest that the PTPN22 gene polymorphisms at 20628A>G and 14943C>T may enhance serum specific IgE responses to TSST-1 and SEA, which may contribute to CU pathogenesis.

Sanitary quality, occurrence and identification of Staphylococcus sp: in food services

Sanitary conditions are essential for the production of meals and control of the presence of pathogensis important to guarantee the health of customers. The aim of this study was to evaluate the sanitary quality of food services by checking the presence of thermotolerant coliforms, Staphylococcus sp. and evaluate the toxigenic potential from the latter. The analysis was performed on water, surfaces, equipment, ready-to-eat foods, hands and nasal cavity of handlers in seven food services. The water used in food services proved to be suitable for the production of meals. Most food, equipment and surfaces showed poor sanitary conditions due to the presence of thermotolerant coliforms (60.6%). Twenty-six Staphylococcus species were identified from the 121 Staphylococcus isolates tested. Staphylococci coagulase-negative species were predominant in the foods, equipment and surfaces. In food handlers and foods, the predominant species was Staphylococcus epidermidis. Twelve different genotypes were found after PCR for the classical enterotoxin genes. The seb gene (19.8%) was the most prevalent among all Staphylococcus sp. Both coagulase-positive and coagulase-negative Staphylococci showed some of the genes of the enterotoxins tested. We conclude that there are hygienic and sanitary deficiencies in the food services analyzed. Although coagulase-positive Staphylococci have not been present in foods there is a wide dispersion of enterotoxigenic coagulase-negative Staphylococci in the environment and in the foods analyzed, indicating a risk to consumer health.

Effects of Zn2+and Zn2+-coordinating glutamic acid residues on the superantigenic activities of staph-ylococcal enterotoxin C2 / 中华微生物学和免疫学杂志

Objective To investigate the role of Zn 2+and Zn2+-coordinating glutamic acid residues ( 71Glu and 80Glu ) in the superantigenic activities of staphylococcal enterotoxin C2 ( SEC2 ) .Methods Over-lap PCR was used to amply genes encoding recombinant mutant proteins rSEC 2 ( E71A), rSEC2 (E80A) and rSEC2 (E71A/E80A).The mutant proteins were expressed in E.coli BL21 (DE3) and puri-fied by affinity chromatography .The differences of biological activities between rSEC 2 and its mutants were compared in vitro.The effects of Zn 2+on the superantigenic activities of rSEC 2 were evaluated by analyzing the proliferation of splenic lymphocytes in the presence or absence of ethylenediaminetetraacetic acid ( EDTA) .Results The substitution of glutamic acid residue at position 71 and 80 by alanine residue had no significant effects on the superantigenic activities and the conformational stability of rSEC 2 mutants.How-ever, traces of Zn2+(10μmol/L) could significantly enhance rSEC2-induced proliferation of splenic lympho-cytes, and only certain amount of Zn 2+could completely restore rSEC2-induced proliferation in the presence of EDTA.Conclusion This study indicated that mutations at Zn 2+-coordinating glutamic acid residues had no significant effects on the conformational stability and the superantigenic activities of SEC 2.Zn2+might play a role in regulating the superantigenic activities of SEC 2 through some indirect ways .

Effect of 20 and 22 amino acid on superantigen activity of staphylococcal enterotoxin C2 / 中国免疫学杂志

Objective:To investigate the improved superantigen activity of SEC2(T20L/G22E) compared with recombinant staphylococcal enterotoxins C 2 ( rSEC2 ).Methods: The proliferation of spleen lymphocytes and T-cell subpopulations induced by rSEC2 and SEC2(T20L/G22E) were examined by WST-1 and flow cytometry separately,and the gene expression of cytokines and Vβspecificities were quantified by real-time PCR.Results: WST-1 and Flow cytometry assays showed that the superantigen activity of SEC2(T20L/G22E) was improved due to enhanced T-cell stimulating potency,resulting in massive activation of T-cells,particularly CD4+and CD8+T-cells.Quantitative real-time PCR assay showed that despite similar Vβspecificities induced by rSEC 2 and SEC2 (T20L/G22E),the quantities of activated T-cells bearing specific Vβwere different,and SEC2(T20L/G22E) could stimulate more gene expression of associated cytokines simultaneously.Conclusion: The results strongly suggested that the increased SEC 2 ( T20L/G22 E)-TCR-binding affinity contributed to more T-cells activation and cytokine release ,which elicit powerful immune activition.

IL-5 Promoter Polymorphism Enhances IgE Responses to Staphylococcal Superantigens in Adult Asthmatics

Interleukin 5 (IL-5) is a key cytokine involved in the induction of T-helper type 2 (Th2) responses in the asthmatic airway. We investigated IL-5 genetic polymorphisms associated with asthma phenotypes, including IgE responses to staphylococcal enterotoxins A and B (SEA and SEB, respectively), in asthmatics. Adult asthmatics (n=310) and normal controls (n=160) were enrolled in the present study. Serum total and specific IgE to SEA and SEB were measured. Two IL-5 polymorphisms, -746A>G and +4499T>G, were genotyped using the primer-extension method. There were no significant differences in genotype or haplotype frequencies of these polymorphisms between the two groups. Asthmatics carrying the AG/GG genotype at -746A>G had a significantly higher prevalence of serum specific IgE to SEA (P=0.008), higher total IgE levels (P=0.014), and lower PC20 methacholine levels (P=0.002) compared to those with the AA genotype. These findings suggest that the IL-5 promoter polymorphism at -746A>G enhances serum total and specific IgE responses to SEA, which may augment airway hyperresponsiveness in adult asthmatics.

Potential Immunoinflammatory Role of Staphylococcal Enterotoxin A in Atopic Dermatitis: Immunohistopathological Analysis and in vitro Assay

BACKGROUND: The underlying mechanism of atopic dermatitis (AD) exacerbated by Staphylococcus aureus has not been established. However, we demonstrated recently that the majority of S. aureus strains colonized in the skin of Korean AD patients carried genes encoding staphylococcal enterotoxin A (SEA) and/or toxic shock syndrome toxin-1 (TSST-1). OBJECTIVE: To clarify the role of staphylococcal superantigen, SEA in AD. METHODS: With the lesional skin of 9 AD patients and normal looking skin of one healthy adult, we examined first the expression of SEA, staphylococcal enterotoxin B (SEB), and TSST-1 using immunohistochemical analysis. In addition, we investigated the effects of SEA on the expression of inflammation-related adhesion molecules and cytokines in human HaCaT keratinocytes and Human Umbilical Vein Endothelial Cells (HUVECs) by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and enzyme-linked immunosorbent assay. RESULTS: Staphylococcal protein A (SPA) and SEA were detected with increased immunoreactivity in AD patients. However, TSST-1 showed mild-to-moderate immunoreactivity in AD patients, whereas SEB was minimally detected. In the double immunofluorescence investigation, SEA and SPA were well co-localized. SEA induced upregulation of adhesion molecules and elicited inflammatory responses in HaCaT keratinocytes and HUVECs. CONCLUSION: This study demonstrates the importance of SEA as an immunoinflammatory triggering factor of AD in Koreans.

Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding / Prevalência de genes codificadores de enterotoxinas e resistência antimicrobiana em estafilococos coagulase-negativo e coagulase-positivo isolados de morcilhas no sul do Brasil

INTRODUCTION: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS) and coagulasepositive (CoPS) isolates from black pudding in southern Brazil. METHODS: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa) and enterotoxin (se) genes was investigated by polymerase chain reaction. RESULTS: The isolates were divided into 2 groups: 75.6% (62/82) were CoNS and 24.4% (20/82) were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8%) and Staphylococcus carnosus (15.9%) were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82) of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6%) and seb (27.5%). CONCLUSIONS: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

INTRODUÇÃO: Estafilococos são patógenos responsáveis por surtos de doenças transmitidas por alimentos. O estudo investigou a prevalência de genes de enterotoxinas e o perfil de resistência aos antimicrobianos em estafilococos coagulase-negativo (CoNS) e estafilococos coagulase-positivo (CoPS) isolados de morcilhas no sul do Brasil. MÉTODOS: Duzentas colônias típicas e atípicas do ágar Baird-Parker foram inoculadas em ágar sal-manitol. Oitenta e dois estafilococos manitol-positivos foram submetidos a testes bioquímicos e perfil de susceptibilidade antimicrobiana. A presença dos genes da coagulase (coa) e enterotoxinas (se) foi investigada por reação em cadeia da polimerase (PCR). RESULTADOS: Os isolados foram divididos em dois grupos: 75,6% (62/82) CoNS e 24,4% (20/82) CoPS. Através dos testes bioquímicos, 9 espécies foram determinadas, Staphylococcus saprophyticus (37,8%) e Staphylococcus carnosus (15,9%) foram as mais prevalentes. Testes de susceptibilidade demostraram fenótipos de resistência aos antibióticos administrados em humanos, como gentamicina, tetraciclina, cloranfenicol e eritromicina. O gene coa foi detectado em 19,5% (16/82) das cepas e quatro fragmentos de DNA polimórficos foram observados. Cinco CoNS contendo o gene coa foram submetidos ao sequenciamento do 16S rRNA e três mostraram similaridade com CoNS. Quarenta amostras foram positivas para pelo menos um gene se, os mais frequentes foram sea (28,6%) e seb (27,5%). CONCLUSÕES: A presença de resistência aos antimicrobianos e de genes se nos isolados de morcilha indicou que este alimento pode representar um risco potencial à saúde, já que a presença nos alimentos pode causar doenças de origem alimentar ou ser uma possível rota de transferência de estafilococos resistentes aos humanos.

Perfil de producción de citoquinas en linfocitos T de sangre periférica de pacientes con poliposis nasal y asma bronquial en respuesta a la estimulación con enterotoxina estafilocócica B / Cytokine production profile in peripheral blood T lymphocytes from patients with nasal poliposis and bronchial asthma in response to staphylococcal enterotoxin B

Introducción: La poliposis nasal (PN) se presenta frecuentemente asociada a asma bronquial (AB). La enterotoxina estafilocócica B (SEB) jugaría un papel en su patogenia. No se ha estudiado si el perfil de citoquinas inducido por SEB en linfocitos T (LT) de pacientes con PNyAB difiere del de controles sanos. Objetivo: Comparar el perfil de citoquinas de LT de sangre periférica de pacientes con PN-AByde controles, estimulados con SEB o concanavalina A (ConA). Material y método: Células mononucleares de sangre periférica de 9 pacientes con PN-AB y de 6 controles se estimularon con SEB o ConA. El porcentaje LT CD4+ productores de interferón (IFN)-y, interleuquina (IL) IL-4, IL-5, IL-17 e IL-21 se determinó mediante citometrfa de flujo. Resultados: El grupo PN-AB presentó un menor porcentaje de LT productores de IL-5 que los controles al estimularse con SEB y con ConA. No hubo diferencia en las otras citoquinas estudiadas. Discusión: Nuestros resultados en sangre periférica difieren de lo descrito en tejido de pólipos nasales. Conclusión: Se sugiere que la respuesta inflamatoria de la PN se originaría localmente ya que los LT de sangre de pacientes con PN-AB no muestran una polarización hacia perfiles proinflamatorios con los estímulos utilizados.

Introduction: Nasal poliposis (NP) is frequently associated with bronchial asthma (BA) and its pathogenesis is still unknown. Staphylococcal enterotoxin B (SEB) has been implicated in the development of NP, however if the SEB-induced cytoklne profile of peripheral blood T lymphocytes (TL) of PN-BA patients differs from that of normal controls has not been studied. Aim: To compare the cytoklne profile of CD4+ TL from NP-BA and controls stimulated with SEB or concanavalin A (ConA). Material and method: Peripheral blood mononuclear cells from 9 NP-BA patients and from 6 controls were stimulated with SEB or ConA. The percentage of interferon (IFN)-y, interleukin {II) 11-4,11-5,11-17, and 11-21 producing TL was analyzed by flow cytometry Results: The percentage of SEB and ConA stimulated CD4+ IL-5-producing TLs was lower in the NP-BA group compared to the control group. There were no differences in the other cytokine-producing populations. Discussion: Unlike what is described in nasal polyp tissue, our findings show a diminished production of IL-5 by peripheral TL from the NP-AB group. Conclusion: A local sinonasal origin of the chronic inflammation is suggested since peripheral blood TL of NP-BA patients do not show a pro-inflammatory polarization with the tested stimuli.

Effect of Staphylococcal Enterotoxin on the Development of Allergic Rhinitis in Mice

BACKGROUND AND OBJECTIVES: The aim of this study is to investigate the role of staphylococcal enterotoxin B (SEB) in the development of allergic rhinitis. MATERIALS AND METHODS: Nasal mucosa and serum were obtained from sensitized mice and control groups, and the frequencies of allergic symptoms, such as sneezing and nasal rubbing, were counted. Eosinophil counts in the nasal mucosa were compared between the study groups. The serum levels of ovalbumin-specific IgE were measured by ELISA. Differences between the sensitized and control groups were statistically analyzed using the Kruskal-Wallis test and the Mann-Whitney U test. RESULTS: The frequencies of sneezing and serum levels of ovalbumin-specific IgE were significantly higher in the groups locally sensitized with SEB than in the control group. On the other hand, they sneezed less frequently and showed lower serum levels of ovalbumin-specific IgE than those in the group locally sensitized with ovalbumin. CONCLUSION: SEB may participate in the pathogenesis of allergic rhinitis although it is a less potent inducer than ovalbumin.

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus Isolates with Toxic Shock Syndrome Toxin and Staphylococcal Enterotoxin C genes / 대한진단검사의학회지

BACKGROUND: Many methicillin-resistant Staphylococcus aureus (MRSA) isolates in Korea possess a specific profile of staphylococcal enterotoxins in that the toxic shock syndrome toxin gene (tst) coexists with the staphylococcal enterotoxin C gene (sec). Because the analysis of staphylococcal cassette chromosome mec (SCCmec), a mobile genetic element mecA gene encoding methicillin resistance, showed that majority of these are SCCmec type II, these MRSA isolates with tst and sec may be genetically related with each other. This study was performed to investigate the genetic relatedness of tstand sec-harboring MRSA strains isolated in Korea by using pulsed-field gel electrophoresis (PFGE). METHODS: A total of 59 strains of MRSA isolates of SCCmec type II possessing tst and sec were selected for PFGE and phylogenetic analyses. These isolates were collected from 13 health care facilities during nationwide surveillance of antimicrobial resistance in 2002. RESULTS: The 59 MRSA isolates were clustered into 11 PFGE types, including one major group of 26 strains (44.1%) isolated from 7 healthcare facilities. Seven PFGE types contained 2 or more isolates each, comprising 55 isolates in total. CONCLUSIONS: Most of SCCmec type II MRSA isolates containing tst and sec showed closely related PFGE patterns. Moreover, MRSA isolates collected from different healthcare facilities showed identical PFGE patterns. These findings suggested a clonal spread of MRSA strains possessing tst and sec in Korean hospitals.

Role of Staphylococcal Superantigen in Atopic Dermatitis: Influence on Keratinocytes

Staphylococcus aureus may perform an crucial function in atopic dermatitis (AD), via the secretion of superantigens, including staphylococcal enterotoxins (SE) A or B, and toxic shock syndrome toxin-1 (TSST-1). Dysregulated cytokine production by keratinocytes (KCs) upon exposure to staphylococcal superantigens (SsAgs) may be principally involved in the pathophysiology of AD. We hypothesized that lesional KCs from AD may react differently to SsAgs compared to nonlesional skin or normal skin from nonatopics. We conducted a comparison of HLA-DR or CD1a expression in lesional skin as opposed to that in nonlesional or normal skin by immunohistochemistry (IHC). We also compared, using ELISA, the levels of IL-1alpha, IL-1beta, and TNF-alpha secreted by cultured KCs from lesional, nonlesional, and normal skin, after the addition of SEA, SEB and TSST-1. IHC revealed that both HLA-DR and CD1a expression increased significantly in the epidermis of lesional skin versus nonlesional or normal skin in quite a similar manner. IL-1alpha, IL-1beta, and TNF-alpha secretion was also significantly elevated in the cultured KCs from lesional skin after the addition of SsAgs. Our results indicated that KCs from lesional skin appear to react differently to SsAgs and increased proinflammatory cytokine production in response to SsAgs may contribute to the pathogenesis of AD.

Fusion Immunotoxin Anti-HER-2-scFv-SEC2 Expressed in E.coli With an Improved Expression Vector pASK75-EX: Its Construction and Functioning / 生物化学与生物物理进展

A tumor-targeting recombinant fusion immunotoxin B-L-SEC2 was constructed by fusing staphylococcal enterotoxin C2 (SEC2) and an anti-HER-2 single-chain Fv B1 through a peptide linker, and expressed in E. coli strain BL21 (DE3) with an improved expression vector pASK75-EX as inclusion body. The denatured inclusion body was purified with Ni-NTA chelate agarose, and then re-natured by dialysis. FACS and MTT assays indicated that the re-natured fusion immunotoxin B-L-SEC2 could target the HER-2 over-expressing breast tumor cell SK-Br-3 in vitro, and inhibit the growth of SK-Br-3.

The Study of SEB/OVA Allergic Rhinitis Mice Model / 医学研究杂志

Objective To establish mice modle of allergic rhinitis(AR) and to study the role of Staphylococcal enterotoxin B(SEB) and ovalbumin(OVA) in the modle.Methods Forty Balb/c mice were evenly randomized into OVA group,SEB group,OVA+SEB group and normal sodium group and AR modle was established.The symptom scores,total serum IgE concentration,IL-4 concentration were analyzed by factorial design.Meanwhile,the morphology change of nasal mucosa was observed.Results The symptom scores in OVA group,SEB group,OVA+SEB group and normal sodium group were 6.80?1.03,0.90?0.99,0.70?0.82,0.60?0.70 respectirely.The interaction of OVA and SEB had statistical significance(P

Effect of regulatory T cell in SEB/OVA allergic rhinitis of animal model / 中国耳鼻咽喉头颈外科

OBJECTIVE To establish mice model of allergic rhinitis(AR) and study the role of Staphylococcal enterotoxin B(SEB)and ovalbumin(OVA)in the model,and investigate the change of regulatory T cell(Treg)in the nasal mucosa of mice.METHODS Forty Balb/c mice were randomized into OVA group(A),SEB group(B),OVA+SEB group(C)and normal solution group(D).AR model was established.The symptom scores and count of Foxp3 positive cells in nasal mucosa were analyzed by factorial design.RESULTS The symptom scores in Group A,B,C,D were 0.90?0.99,0.70?0.82,6.80?1.03,0.60?0.70 respectively.Group C was successfully established as AR model.OVA and SEB had interaction(P

Increase of Rhinovirus Replication in Airway Epithelial Cells by Staphylococcal Enterotoxin A and B / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES : The toxins generated from Staphylococcus aureus, Staphylococcal enterotoxin A (SEA) and B (SEB), are reported to have an important role in the pathogenesis of chronic rhinosinusitis. As a basic step for elucidating the pathophysiologic responses of the nasal mucosa of chronic rhinosinusitis associated with rhinovirus infection, this study investigated the effect of SEA and SEB on rhinovirus infection in A549 cells. MATERIALS AND METHOD : The effect of SEA and SEB on the rhinovirus-induced changes in intercellular adhesion molecule-1 (ICAM-1) expression was assessed by flow cytometry. The effect of staphylococcal toxins on the rhinovirus-induced cytokine secretion was measured by ELISA. The effect of the replication of rhinovirus in the cells was examined by viral culture with subsequent determination of viral titer. RESULTS : ICAM-1 expression was increased in the rhinovirus infection group. Cytokine secretion was also increased in the rhinovirus infection group. But there was no additional increase due to staphylococcal toxins regarding the ICAM-1 expression and cytokine secretions. Staphylococcal toxins increased viral titer in proportion to toxin concentrations. CONCLUSION : SEA and SEB increased rhinoviral replication in airway epithelial cells. This result shows that airway epithelial cells with chronic rhinosinusitis are more favorable environments for rhinovirus infection.

Expression of Toll-like Receptors on the Macrophages Activated by Bacterial Superantigens / 감염과화학요법

BACKGROUND: Staphylococcal enterotoxin B (SEB) as a prototype superantigen is known to play a pivotal role in toxic shock syndrome and severe sepsis. However, the precise mechanism initiating the activation of innate effector cells by SEB is unclear. Recently, Toll-like receptors (TLRs), the sensor of pathogen associated molecular pattern (PAMP), have been reported to be expressed abundantly in monocytic lineage-cells. The purpose of this study is to investigate whether TLRs are involved in the SEB-induced immune cell activation and to prove the differential TLRs expression in response to SEB and/or lipopolysaccharide (LPS). MATERIALS AND METHODS: SEB was purified by dye ligand affinity chromatography. The mRNA expression of TLR1-9 in human peripheral blood mononuclear cells (PBMC) and human monocyte- like THP-1 cell line stimulated by SEB and/or LPS was detected by RT-PCR. RESULTS: The treatment of PBMC with SEB elicited significant changes in the expression of several TLRs. Interestingly, the mRNAs of TLR1 and TLR5 were clearly up-regulated in PBMC, whereas mRNA of TLR4 was down-regulated in the very early period of stimulation within 1-2 hours, and subsequently up-regulated 3 hours later after the stimulation. The up-regulation of mRNA of TLR4 was detected in PBMC stimulated by LPS. The up-regulation was more prominent in the cells exposed concomitantly to SEB and LPS. The mRNA expression pattern of TLR4 in THP-1 cell line stimulated by SEB or LPS was comparable to those of PBMC. CONCLUSION: This study indicates that SEB triggers inflammatory signals on macrophages and PBMC by engaging TLRs, particularly TLR4. The combination of LPS and SEB synergistically modulates TLR4 signaling.