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1
SU, YI-CHENG, and AMY C. L. WONG. "Optimal Condition for the Production of Unidentified Staphylococcal Enterotoxins." Journal of Food Protection 56, no. 4 (1993): 313–16. http://dx.doi.org/10.4315/0362-028x-56.4.313.
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The sac culture method in combination with 6% NZ-Amine A plus 1% yeast extract was found to be the optimal condition for staphylococcal enterotoxins A (SEA) and D (SED) production. This growth condition was tested for the production of unidentified staphylococcal enterotoxins (SEs). Twenty-one Staphylococcus aureus strains that previously showed an emetic response in monkeys but were negative for any of the identified SEs when cultured by the membrane-over-agar method were grown by the sac culture method. All 21 strains produced at least one known SE. One strain produced only enterotoxin C (SEC). Nine strains produced only SED. One strain produced both SEA and SED. Four produced both SEC and SED. One produced SEA, enterotoxin B (SEB), and SED. Two produced SEA, SEC, and SED. Three produced SEA, SEB, SEC, and SED. One of these strains, FRI-569, that produced only SED at a low level (10 ng/ml) was selected to confirm the production of an unidentified SE by the monkey feeding test. Emesis was induced in five out of six monkeys. The total amount of SED in the supernatant fluids fed to monkeys was only 0.5 μg, or 2.5% of the 50% emetic dose (20 μg). Production of an unidentified SE by strain FRI-569 was therefore confirmed. This optimal condition can be used to produce increased amounts of unidentified SEs for purification.
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Kahraman, Beren Basaran, Recep Geckinli, and Seyyal Ak. "Detection of enterotoxigenic Staphylococcus aureus in raw and pasteurized milk." Veterinarski arhiv 94, no. 1 (2024): 33–42. http://dx.doi.org/10.24099/vet.arhiv.2038.
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The aim of this study was to investigate staphylococcal enterotoxins (SEs) by ELISA, and detect the five classical sea, seb, sec, sed, and see genes by real-time PCR in Staphylococcus aureus isolates from raw and pasteurized milk samples. Staphylococcus spp. were isolated from 98 out of 100 raw milk samples, and in 6 out of 100 pasteurized milk samples. On further biochemical tests, S. aureus was isolated in 48 samples (48%) of raw milk (n=100) and in one sample (1%) of pasteurized milk (n=100). Ten (10%) out of 100 raw milk samples were positive for at least one enterotoxin, and the most frequently observed SE was SEA (10%), followed by SEE (7%) and SEB (6%), but none of the isolates were positive for SEC and SED. At least one of the SEs gene types (sea, seb, sec, sed, see) was detected in 45 (93.8%; 45/48) S. aureus isolates from raw milk samples. sec, sea, seb, sed, and see genes were observed in 56.2%, 39.5%, 31.2%, 29.1% and 14.5% of strains respectively. The enterotoxin genes were the single type in 21 (46.7%) of the 45 isolates, there were two in 15 (33.3%), three in six (13.3%), four in two (4.4%), and one (2.2%) in all gene regions. The SE gene was not detected in the S. aureus (n=1) isolate from pasteurized milk. As a result of this study, the presence of enterotoxigenic S. aureus in raw milk was revealed, and it was pointed out that these SEs may contribute to cases of staphylococcal foodborne poisoning (SPF).
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CENCI-GOGA, B. T., M. KARAMA, P. V. ROSSITTO, R. A. MORGANTE, and J. S. CULLOR. "Enterotoxin Production by Staphylococcus aureus Isolated from Mastitic Cows." Journal of Food Protection 66, no. 9 (2003): 1693–96. http://dx.doi.org/10.4315/0362-028x-66.9.1693.
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Staphylococcus aureus is an important cause of mastitis in cows. The ability of S. aureus strains to produce one or more enterotoxins in milk and dairy products is linked to staphylococcal food poisoning. To determine whether staphylococci causing bovine mastitis could cause human foodborne intoxication, the production of staphylococcal enterotoxins A through D (SEA, SEB, SEC, and SED) by 160 S. aureus isolates was evaluated with the use of a reverse passive latex agglutination enterotoxin kit. All S. aureus strains were isolated over a 9-month period from 2,343 routine submissions of a composite quarter collection of individual mastitic cows at 18 dairy farms in the San Joaquin Valley in California. Prior to enterotoxin detection, isolates were grown by a method that enhances the in vitro synthesis of enterotoxin. Twenty-two of 160 S. aureus isolates produced enterotoxin. Seven produced SEC, 12 produced SED, and 3 produced both SEC and SED. None of the isolates produced SEA or SEB.
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SORIANO, J. M., G. FONT, H. RICO, J. C. MOLTÓ, and J. MAÑES. "Incidence of Enterotoxigenic Staphylococci and Their Toxins in Foods." Journal of Food Protection 65, no. 5 (2002): 857–60. http://dx.doi.org/10.4315/0362-028x-65.5.857.
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Of 504 food samples collected from cafeterias, 19 (3.8%) yielded strains of enterotoxigenic staphylococci, and 10 (52.6%), 4 (21.1%), 3 (15.8%), and 2 (10.5%) of these strains produced enterotoxins C (SEC), D (SED), B (SEB), and A (SEA), respectively. Moreover, SEA, SEB, and SEC were isolated from three hamburger samples. Of 181 food samples collected from four restaurants before the implementation of the hazard analysis and critical control point (HACCP) system, 7 (3.9%) were found to contain enterotoxigenic strains, and SED, SEC, and SEA were produced by 4 (57.1%), 2 (28.6%), and 1 (14.3%) of these strains, respectively. One meatball sample with SEC was detected in a restaurant. After the implementation of the HACCP system in four restaurants, neither enterotoxigenic staphylococci nor enterotoxins were detected in 196 studied samples.
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Naffa, Randa G., Salwa M. Bdour, Hussein M. Migdadi, and Asem A. Shehabi. "Enterotoxicity and genetic variation among clinical Staphylococcus aureus isolates in Jordan." Journal of Medical Microbiology 55, no. 2 (2006): 183–87. http://dx.doi.org/10.1099/jmm.0.46183-0.
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A total of 100 Jordanian clinical Staphylococcus aureus isolates was analysed for the presence of the enterotoxin genes sea, seb, sec, sed and see using multiplex PCR. Twenty-three isolates (23 %) were potentially enterotoxigenic. The prevalence of sea, sec and sea plus sec among the total clinical isolates was 15, 4 and 4 %, respectively. None of the isolates harboured sed, seb or see genes. S. aureus isolates were subjected to DNA fingerprinting by randomly amplified polymorphic DNA (RAPD) analysis to test whether isolates harbouring the toxin genes were genetically clustered. A total of 13 genotypes was identified at a 47 % similarity level. Genotypes I and V accounted for the largest number of enterotoxigenic isolates (19 %). This study has demonstrated the genetic diversity of Jordanian clinical S. aureus isolates and shown that the presence of the toxin genes is not genotype specific.
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ADESIYUN, ABIODUN A., IFEDAPO RAJI, and VIVIAN YOBE. "Enterotoxigenicity of Staphylococcus aureus from Anterior Nares of Dining Hall Workers." Journal of Food Protection 49, no. 12 (1986): 955–57. http://dx.doi.org/10.4315/0362-028x-49.12.955.
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The frequency of isolation of enterotoxigenic Staphylococcus aureus in dining hall workers of a Nigerian University was determined. Of a total of 186 workers sampled, 47 (25.3%) were carriers of enterotoxigenic S. aureus in their anterior nares, including 19 (22.4%) of 85 cooks and 11 (23.9%) of 46 stewards. Fifty-five (26.6%) of 207 strains of S. aureus tested produced staphylococcal enterotoxins A (SEA), B (SEB), C (SEC), D (SED) or E (SEE). SEA predominated, with 18 (8.7%) strains elaborating it and representing 32.7% of all enterotoxigenic strains. SEC and SED were produced by 14 (6.8%) and 13 (6.3%) strains, respectively, and 9 (4.3%) strains produced SEB and SEE. It appears that SEA poses the greatest risk to students consuming foods contaminated by S. aureus of nasal origin from these workers.
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Lapeyre, Christiane, Tiphaine Maire, Sabine Messio, and Sylviane Dragacci. "Enzyme Immunoassay of Staphylococcal Enterotoxins in Dairy Products with Cleanup and Concentration by Immunoaffinity Column." Journal of AOAC INTERNATIONAL 84, no. 5 (2001): 1587–92. http://dx.doi.org/10.1093/jaoac/84.5.1587.
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Abstract Two different immunoaffinity columns (IACs) were prepared for detection of staphylococcal enterotoxins (SETs) from dairy products. First, a specific IAC for staphylococcal enterotoxin A (SEA), IAC-1, was prepared by coupling monoclonal antibody (mAb) directed against SEA; second, a polyspecific IAC for SEA, staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SECs), and staphylococcal enterotoxin D (SED), IAC-2, was prepared by coupling a mixture of mAbs against SEA, SECs, and SED, and rabbit IgG against SEB. These columns were applied for detection of SETs in dairy products, after extraction, immunoaffinity chromatography, and enzyme immunosorbent assay (EIA). Overall recoveries from dairy products spiked with 1 ng SEA/25 g averaged 81.2% (range, 76–85%) on IAC-1. The repeated use of IAC-1 was then determined with good efficiency of 91.5%, in more than 10 runs. On the other hand, a recovery yield of 77%of SETs (SEA, SEB, SEC, and SED) from dairy products spiked with 2.5 ng of each enterotoxin per 25 g, was obtained with IAC-2. IAC-2 was also successfully subjected to the chromatography of naturally contaminated foods implicated in staphylococcal food poisoning outbreaks. This new extraction–concentration–immunoaffinity–chromatography method (ECIC) is very useful for improving staphylococcal enterotoxin detection and eliminating matrix effect in EIA of dairy products.
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Radoslava, Savić Radovanović, Zdravković Nemanja, and Velebit Branko. "Occurrence and Characterization of Enterotoxigenic Staphylococci Isolated from Soft Cheeses in Serbia." Acta Veterinaria 70, no. 2 (2020): 238–54. http://dx.doi.org/10.2478/acve-2020-0017.
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AbstractA total of 415 cheese samples produced with raw or cooked milk collected from local markets were analysed for the presence of coagulase-positive staphylococci. In 85 (20.48%) samples the presence of coagulase positive staphylococci was detected. The ELFA technique VIDAS SET2 (BioMerieux, France) was used for testing coagulase-positive staphylococci strains to produce classical enterotoxins (SEA, SEB, SEC, SED, SEE), and to determine the enterotoxins in cheese samples. The number of coagulase-positive staphylococci in cheese samples ranged from 1-5.79 log CFU g-1. Out of 85 coagulase-positive strains 26 (30.59%) produced enterotoxins. The presence of genes for the synthesis of staphylococcal enterotoxins (SE) in the obtained extracts of DNA from 26 enterotoxigenic strains was detected by conventional multiplex PCR technique (for genes sea and seb) i.e. the Real-Time PCR technique for genes sec, sed and see. In all 26 strains of coagulase-positive staphylococci (originating from cheeses produced from raw or cooked milk, which were enterotoxin producers) sea was present, and in 24 strains in addition to sea gene, seb was detected. None of the isolates possessed genes for the synthesis of enterotoxin C (SEC), D (SED) and E (SEE). Out of 26 tested cheese samples positive for enterotoxigenic coagulase-positive staphylococci, enterotoxin was detected in 2 (7.69%) samples of sweet-coagulating cheese, in which the number of enterotoxigenic coagulase-positive staphylococci exceeded 5 log CFU g-1. In sweet-coagulating cheeses in which the number of coagulase-positive staphylococci exceeds 5 log CFU g-1 and the pH value was higher than 5.0, enterotoxins may be present in amounts sufficient to cause intoxication.
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Pexara, Andreana, Nikolaos Solomakos, Daniil Sergelidis, and Alexandros Govaris. "Fate of enterotoxigenicStaphylococcus aureusand staphylococcal enterotoxins in Feta and Galotyri cheeses." Journal of Dairy Research 79, no. 4 (2012): 405–13. http://dx.doi.org/10.1017/s0022029912000325.
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In this study the fate of enterotoxigenicStaphylococcus aureusand staphylococcal enterotoxins in Feta and Galotyri cheeses were studied. Initially, the enterotoxigenic abilities of fourStaph. aureusLHA, LHB, LHC and LHD strains isolated from raw ovine milk were examined in both BHI broth and ovine milk. In BHI broth, theStaph. aureusLHA, LHB, LHC and LHD strains were found toxigenic at 37 °C producing the staphylococcal enterotoxins (SEs) serotypes SEA, SEB, SEC and SED, respectively, whereas in ovine milk at 37 °C,Staph. aureusLHD was found to produce only SED, while no SE production was observed for the other examined strains. Thus, the fate of onlyStaph. aureusLHD and SED were examined in Feta and Galotyri cheeses. The cheeses were made from raw ovine toxic milk with preformed SED or raw ovine milk contaminated with high (ca 6 log cfu/ml) and low inocula (ca 3 log cfu/ml) ofStaph. aureusLHD. Results showed that the pathogen was eliminated at slower rate in Galotyri cheese than in Feta cheese, for the high (5 d vs. 16 d) or the low (1 d vs. 12 d) inoculum trials. In both cheeses produced from the toxic milk, SED was detected during manufacturing and storage. SED was also detected in the curd (2 h), whenStaph. aureusLHD populations had reached ca 7 log cfu/g, and up to the end of storage for the high inoculum trials of both cheeses. No SED was observed for the low inoculum trials of either cheese.
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Angarita-Merchán, Maritza, and Nuri Andrea Merchán Castellanos. "Genes codificantes para enterotoxinas de aislados estafilocócicos coagulasa negativos y coagulasa-positivos a partir muestras con mastitis bovina." Revista Investigación en Salud Universidad de Boyacá 5, no. 2 (2018): 205–18. http://dx.doi.org/10.24267/23897325.267.
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Introducción: La mastitis bovina es la inflamación de glándulas mamarias y tejidos secretores. El género Staphylococcus es el agente causal más importante, por su capacidad de producir diferentes factores de virulencia. Las enterotoxinas estafilocócicas son un grupo importante de toxinas que permiten al microorganismo invadir células y tejido huésped, siendo diseminadas a través de productos alimenticios y responsables de graves intoxicaciones alimentarias en el mundo.
 Objetivo: Determinar la presencia de genes codificantes para enterotoxinas estafilocócicas (SE); SEA, SEB, SEC, SED y SEE, en cepas de Staphylococcus spp. asociados a mastitis bovina.
 Materiales y Métodos: Estudio cuantitativo, descriptivo y transversal. Se realizó identificación de especie a través de la amplificación de la región r16S. La detección de genes sea, see, sec, sed, y see se realizó mediante la amplificación por PCR convencional, usando iniciadores específicos para cada gen y se evidenciaron los amplicones a través de electroforesis.
 Resultados: Se evidenció el predominio del grupo Staphylococcus coagulasa positivo (65.2%), siendo Staphylococcus aureus la cepa con mayor presencia (88.5%), mientras que Staphylococcus coagulasa negativo fue del 37.5%. El gen sea fue detectado en Staphylococcus sciuri (1.7%); seb en Staphylococcus pasteuri y Staphylococcus warneri (3.6%); sec fue identificado en Staphylococcus sciuri y Staphylococcus saprophyticus (3.6%); no se detectaron los genes sed y see en ninguna de las cepas evaluadas.
 Conclusiones: Los resultados apoyan la evidencia que el desarrollo de mastitis bovina también es causado por Staphylococcus Coagulasa Negativa, indicando la posibilidad que este grupo adquiera atributos genéticos como enterotoxinas y factores de virulencia por transferencia horizontal.
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Mebkhout, F., L. Mezali, T. M. Hamdi, et al. "Prevalence and distribuion of staphylococcal enterotoxin genes among Staphylococcus aureus isolates from chicken and turkey carcasses in Algeria." Journal of the Hellenic Veterinary Medical Society 69, no. 4 (2019): 1297. http://dx.doi.org/10.12681/jhvms.19621.
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This study is aimed to determine the prevalence of staphylococcus aureus (S.aureus) by biochemical tests in poultry carcasses. It is also intend to detect the distribution of genes for classical staphylococcal enterotoxins A, B, C, D and E (sea, seb, sec, sed and see) and for gene femA, specific for S.aureus species, using multiplex PCR. A total of 385 samples of neck skins from fresh poultry carcasses were collected during the period 2012-2013 from 16 different slaughterhouses located in the region of Algiers, Algeria. The overall prevalence of S.aureus in freshly slaughtered poultry carcasses was 41.56%, with an individual prevalence of 40.63% and 45.71% for chicken and turkey respectively. From the 95 strains of S.aureus identified by biochemical tests, 82 (86.32%) isolates were femA positive using multiplex PCR. The investigation has also revealed the presence of both enterotoxins B and D, with a predominance of seb (13.33%) followed by sed (1.67%), in the chicken carcasses while in turkey only sed was detected (4.55%) It has been found that strains of S.aureus of poultry origin can be enterotoxigenic with the predominance of genes encoding for enterotoxins seb in chicken and sed in turkey. As enterotoxins can be produced in adequate amounts to induce foodborne illnesses, these potential dangers must be considered in terms of a real risk to public health.
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Borelli, B. M., I. C. A. Lacerda, L. R. Brandão, et al. "Identification of Staphylococcus spp. isolated during the ripening process of a traditional minas cheese." Arquivo Brasileiro de Medicina Veterinária e Zootecnia 63, no. 2 (2011): 481–87. http://dx.doi.org/10.1590/s0102-09352011000200028.
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The population dynamics of Staphylococcus spp. was studied during the ripening of Canastra Minas cheese at three farms located in the State of Minas Gerais, Brazil. The presence of coagulase (coa), thermonuclease (nuc), and enterotoxin (sea, seb, sec, and sed) genes was investigated in Staphylococcus strains isolated during the 60-day cheese-ripening period. The presence of the staphylococcal enterotoxins A, C, and D was also investigated in the cheese samples. Cheese samples that were matured for 0, 7, 15, 30, and 45 days presented staphylococci counts from 10³ to 10(8)cfu/g. All isolates considered coagulase-positive by physiological tests had the coa gene. However, no association was observed between the results obtained with biochemical tests and those obtained by PCR using gene-specific primers for coagulase-negative strains. Coagulase and thermonuclease genes occurred simultaneously in 41.3% of Staphylococcus spp. tested. None of the investigated Staphylococcus strains expressed enterotoxins SEA, SEB, SEC, and SED. Enterotoxins A, C, and D were not detected in any of the cheese samples.
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Shinagawa, Kunihiro, Katsuhiko Omoe, Naonori Matsusaka, and Shunji Sugii. "Immunological studies on staphylococcal enterotoxin D: production of murine monoclonal antibodies and immunopurification." Canadian Journal of Microbiology 37, no. 8 (1991): 586–89. http://dx.doi.org/10.1139/m91-099.
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Eight murine monoclonal antibodies (MAbs) against staphylococcal enterotoxin D (SED) were obtained by fusion of myeloma cells with mouse spleen cells immunized with SED only or a combination of SED and either enterotoxin A (SEA) or enterotoxin E (SEE). When only SED was used as an immunogen, six MAbs were specific for SED only, whereas one MAb was reactive with both SED and SEE when both SEs were used as immunogens. One MAb reacted with SEA, SED, and SEE when both SEA and SED were used as immunogens. A MAb with the highest reactivity to SED was used to prepare an immunosorbent for purification of SED by immunoaffinity chromatography. Approximately 70% of the partially purified SED was recovered in the eluate. The purified SED was electrophoretically and antigenically pure. Immunoaffinity chromatography proved useful in the purification of SED in terms of ease of purification, percent enterotoxin, and enterotoxin purity. Key words: enterotoxin D, monoclonal antibodies, Staphylococcus aureus.
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Fowoyo, P. T., and S. T. Ogunbanwo. "Virulence and toxigenicity of coagulase-negative staphylococci in Nigerian traditional fermented foods." Canadian Journal of Microbiology 62, no. 7 (2016): 572–78. http://dx.doi.org/10.1139/cjm-2015-0752.
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The incidence of coagulase-negative staphylococci (CoNS) may render food unsafe, as the clinical isolates have been reported to exude virulent traits. A total of 255 CoNS isolates from 6 traditional fermented foods (nono, kunu, wara, iru, ogi, and kindirmo) from North Central Nigeria, identified as Staphylococcus epidermidis, Staphylococcus simulans, Staphylococcus xylosus, Staphylococcus kloosii, and Staphylococcus caprae, were investigated for virulence traits. The strains were examined for biofilm formation and production of hyaluronidase, DNase, TNase, haemolysins, and superantigenic toxins (SEA, SEB, SEC, SED, and TSST-1) using standard and genotypic methods. The analysis of virulence factors revealed the production of slime in 200 isolates (78.4%); α-haemolysin in 136 (53.3%); β-haemolysin in 43 (16.9%); DNase in 199 (78.0%); TNase in 29 (11.4%); hyaluronidase in 125 (49.0%); TSST-1 in 119 (46.7%); and enterotoxin-producing isolates SEA, SEB, SEC, and SED in 61 (23.9%), 19 (7.5%), 9 (3.5%), and 8 (3.1%), respectively. PCR analysis detected tsst-1, sea, seb, and sec genes. The ability of these microorganisms to exhibit virulence evokes the potential to cause disease especially under determinate conditions or in immune-compromised patients. The occurrence of CoNS in food should not be ignored nor their pathogenic potential considered as insignificant, rather safety measures should be taken to reduce or totally eliminate their occurrence in foods.
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Baranska-Rybak, Wioletta, Oscar Cirioni, Malgorzata Dawgul, et al. "Activity of Antimicrobial Peptides and Conventional Antibiotics against Superantigen Positive Staphylococcus aureus Isolated from the Patients with Neoplastic and Inflammatory Erythrodermia." Chemotherapy Research and Practice 2011 (May 12, 2011): 1–6. http://dx.doi.org/10.1155/2011/270932.
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Superantigens are proteins comprising a group of molecules produced by various microorganisms. They are involved in pathogenesis of several human diseases. The aim of the study was the comparison of susceptibility to antibiotics and antimicrobial peptides (AMPs) of Staphylococcus aureus (SA) strains producing staphylococcal enterotoxins SEA, SEB, SEC, SED, and TSST-1 and nonproducing ones. In the group of the total 28 of the patients with erythrodermia the presence of SA was confirmed in 24 cases. The total of 14 strains of SA excreted enterotoxins SEA, SEC, SED, and TSST-1. We did not observe that strains producing mentioned superantigens were less susceptible to AMPs (aurein 1.2, citropin 1.1, lipopeptide, protegrin 1, tachyplesin 3, temporin A, and uperin 3.6). The opposite situation was observed in conventional antibiotics. SA strains excreting tested superantigens had higher MICs and MBCs than nonproducing ones. The interesting finding considering the high efficacy of AMPs, against all examined strains of SA, makes them attractive candidates for therapeutic implication.
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Hu, Dong-Liang, Katsuhiko Omoe, Yu Shimoda, Akio Nakane, and Kunihiro Shinagawa. "Induction of Emetic Response to Staphylococcal Enterotoxins in the House Musk Shrew (Suncus murinus)." Infection and Immunity 71, no. 1 (2003): 567–70. http://dx.doi.org/10.1128/iai.71.1.567-570.2003.
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ABSTRACT The emetic responses induced by staphylococcal enterotoxin A (SEA), SEB, SEC2, SED, SEE, SEG, SEH, and SEI in the house musk shrew (Suncus murinus) were investigated. SEA, SEE, and SEI showed higher emetic activity in the house musk shrew than the other SEs. SEB, SEC2, SED, SEG, and SEH also induced emetic responses in this animal model but relatively high doses were required. The house musk shrew appears to be a valuable model for studying the mechanisms of emetic reactions caused by SEs.
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NÁJERA-SÁNCHEZ, GABRIELA, ROGELIO MALDONADO-RODRÍGUEZ, PATRICIA RUÍZ OLVERA, and LYDIA MOTA de la GARZA. "Development of Two Multiplex Polymerase Chain Reactions for the Detection of Enterotoxigenic Strains of Staphylococcus aureus Isolated from Foods." Journal of Food Protection 66, no. 6 (2003): 1055–62. http://dx.doi.org/10.4315/0362-028x-66.6.1055.
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Two multiplex polymerase chain reactions were developed for the detection of enterotoxigenic strains of Staphylococcus aureus: one multiplex reaction for the simultaneous detection of enterotoxigenic strains type A (entA), type B (entB), and type E (entE) and another for the simultaneous detection of enterotoxigenic strains type C (entC) and type D (entD). Both reactions were standardized with the use of the reference enterotoxigenic strains of S. aureus: FRI 722, producer of staphylococcal enterotoxin (SE) type A (SEA); FRI 1007, producer of SEB; FRI 137, producer of SEC1; FRI 472, producer of SED; and FRI 326, producer of SEE. Optimized methods were used to determine the presence of enterotoxigenic types for 51 S. aureus strains isolated from meat (sausage, ham, and chorizo) and dairy (powdered milk and cheese) products by the Baird-Parker technique. The enterotoxigenic capacities of the strains were determined by the indirect enzyme-linked immunosorbent assay (ELISA) with the use of reference staphylococcal toxins and antitoxins. Fifty of the 51 strains isolated were enterotoxigenic and produced one to four enterotoxin types, with the most frequently produced types being SEA and SED. Levels of correlation between the presence of genes that code for the production of SE (as determined by polymerase chain reaction) and the expression of these genes (as determined by the indirect ELISA) were 100% for SEA and SEE, 86% for SEC, 89% for SED, and 47% for SEB.
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Ferreira, Daneelly H., Maria das Graças X. Carvalho, Maria J. Nardelli, Francisca G. C. Sousa, and Celso J. B. Oliveira. "Occurrence of enterotoxin-encoding genes in Staphylococcus aureus causing mastitis in lactating goats." Pesquisa Veterinária Brasileira 34, no. 7 (2014): 633–36. http://dx.doi.org/10.1590/s0100-736x2014000700004.
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Staphylococcal enterotoxins are the leading cause of human food poisoning worldwide. Staphylococcus spp. are the main mastitis-causing agents in goats and frequently found in high counts in goat milk. This study aimed to investigate the occurrence of enterotoxin-encoding genes in Staphylococcus aureus associated with mastitis in lactating goats in Paraiba State, Brazil. Milk samples (n=2024) were collected from 393 farms. Staphylococcus aureus was isolated in 55 milk samples. Classical (sea, seb, sec, sed, see) and novel (seg, seh, sei) enterotoxin-encoding genes were investigated by means of polymerase chain reaction (PCR). From thirty-six tested isolates, enterotoxin-encoding genes were detected in 7 (19.5%) S. aureus. The gene encoding enterotoxin C (seC) was identified in six isolates, while seiwas observed in only one isolate. The genes sea, seb, sed, see, seg and seh were not observed amongst the S. aureus investigated in this study. In summary, S. aureus causing mastitis in goats can harbor enterotoxin-encoding genes and seC was the most frequent gene observed amongst the investigated isolates. This finding is important for surveillance purposes, since enterotoxin C should be investigated in human staphylococcal food poisoning outbreaks caused by consumption of goat milk and dairy products.
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CHOU, CHENG-CHUN, and LI-FEN CHEN. "Enterotoxin Production by Staphylococcus warneri CCRC 12929, a Coagulase-Negative strain." Journal of Food Protection 60, no. 8 (1997): 923–27. http://dx.doi.org/10.4315/0362-028x-60.8.923.
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Production of staphylococcal enterotoxin A (SEA) and enterotoxin D (SED) by Staphylococcus warneri was first examined in three different media including brain heart infusion (BHI) broth, NZ-amine (NZA) medium, and 3 + 3 medium containing 3% NZ-amine A plus 3% Hy-Case Amino. Results of these investigations revealed that S. warneri produced the highest amount of SEA in BHI broth. SED yields were higher when BHI broth or NZA medium was used as the culture medium. On the other hand, SEA and SED production was found to be lowest in 3 + 3 medium. Further study showed that the optimum pH, for both SEA production and SED production was 7.0. Addition of 10% (wt/vol) sodium chloride to BHI broth reduced enterotoxin production by S. warneri. SEA production was reduced and SED production was completely inhibited in the presence of 15% (wt/vol) NaCl. Supplementation of the media with 0.4 or 1.5 mM magnesium sulfate markedly reduced SED production by S. warneri. Reduced production of both SEA and SED was also observed when BHI broth was supplemented with 0.1 M glucose or glycerol.
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OH, SU KYUNG, NARI LEE, YOUNG SUN CHO, DONG-BIN SHIN, SOON YOUNG CHOI, and MINSEON KOO. "Occurrence of Toxigenic Staphylococcus aureus in Ready-to-Eat Food in Korea." Journal of Food Protection 70, no. 5 (2007): 1153–58. http://dx.doi.org/10.4315/0362-028x-70.5.1153.
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Toxigenic Staphylococcus aureus contamination in ready-to-eat (RTE) food is a leading cause of foodborne illness in Korea. To monitor food contamination by S. aureus, a total of 3,332 RTE food samples were selected from nationwide wholesale marts between 2003 and 2004 and examined. A total of 285 (8.6%) of the overall samples were contaminated by S. aureus. According to the analysis, 31.6% of the tested cream-cakes, 19.8% of the raw fish, and 19.3% of the rice cakes with filling were contaminated with S. aureus. Forty-seven percent of the strains isolated from the contaminated food were enterotoxigenic S. aureus. The phenotypic result of the strain isolated from food showed that 48% of the strains produced one or more toxins, such as staphylococcal enterotoxins A, B, and C (SEA, SEB, and SEC). At least one SEA was produced by over 90% of the toxigenic strains. Other toxins, such as SEB, SEC, SED, SEA+SEC, and SEC+SED, were each detected. Toxic shock syndrome toxin 1 (TSST-1), a causative agent of toxic shock syndrome, was detected in 13 strains of the toxigenic isolates from the food. As the result of genotyping, 22 strains with a toxin gene that was not detected in the phenotypic analysis were also detected. Sixty-nine percent of the toxigenic strains had at least one sea gene, and the most prevalent genotype was sea+seh (34.4%), followed by sea (18.8%) and sea+seg+sei (15.6%). The tst gene encoding TSST-1 was found in 13 strains (13.5%). The genes (eta and etb) encoding exfoliative toxins A and B were not detected in any of the samples.
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Kaefer, Kauana, Débora Rodrigues Silveira, Juliana Fernandes Rosa, Thaís Gonçalves Gonçalves, Thamíris Pereira de Moraes, and Cláudio Dias Timm. "Phenotypic and genotypic characterization of Staphylococcus aureus isolated from pork sausage." Research, Society and Development 10, no. 2 (2021): e59910212041. http://dx.doi.org/10.33448/rsd-v10i2.12041.
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The objective of this study was to characterize the genotype and phenotype of S. aureus isolates from pork sausages. Fifty samples of pork sausages were collected, counts of coagulase-positive Staphylococcus were made and isolates were obtained to identify S. aureus species. In the isolates, the presence of genes sea, seb, sec, and sed was surveyed, the methicillin-resistance was assessed and the production of biofilm in Congo red agar, stainless steel, polyethylene, glass, and pork casing was tested. The capacity of biofilm formation was assessed after the exposure to sublethal stress. Of the samples tested, 12% had counts superior to what is permitted by the legislation. S. aureus was isolated in 44% of the samples. Of these, 54% had only the gene sed and 32% had genes sec and sed, 73% were classified as methicillin-resistant S. aureus (MRSA). Of the MRSA isolates, 62% had only gene sed and 35% had both genes found in this study. Regarding the biofilm formation in Congo red agar, 68% of S. aureus isolates were considered as biofilm formers. After undergoing the sublethal stress, most of the biofilm former isolates proceeded to form biofilm and the non-biofilm former isolates responded in a distinct manner. The condition in which the sublethal stress greatly induced the biofilm formation was the cold. Biofilm production was observed only in the stainless steel and pork casing in 71% and 57% of the isolates tested, respectively. Thus, we stress the importance of implementing good manufacturing practices within the industry to control microbial contamination and biofilm formation.
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Mašlanková, Jana, Ivana Pilipčincová, and Ľudmila Tkáčiková. "Pheno- and Genotyping of Staphylococcus aureus Isolates of Sheep Origin." Acta Veterinaria Brno 78, no. 2 (2009): 345–52. http://dx.doi.org/10.2754/avb200978020345.
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The aim of the study was to determine the prevalence of genes encoding virulence factors in Staphylococcus aureus strains isolated from raw sheep milk, sheep cheese and Bryndza cheese. Genes encoding staphylococcal enterotoxin (sea, seb, sec, sed and see), toxic shock syndrome toxin-1 (tst), exfoliative toxins (eta and etb) and collagen-binding protein (cna) were detected. In a total of 79 S. aureus isolates all assessed toxins encoding genes were found, except for see, eta and etb. Overall, 75.9% of S. aureus isolates were found to be positive for one or more toxin genes. The sec gene was found most frequently (24.1%), followed by tst (22.8%), seb (13.9%), sed (10.1%) and sea (5.1%). The cna gene was detected in 55.7% of S. aureus isolates. Based on tandem repeats in coa gene, five coa types were observed, further divided into 16 subtypes based on their RFLP pattern. Similarly tandem repeats in spa gene divided S. aureus isolates into 7 types. In the parallel antibiotic resistance study, 69.6% isolates were resistant to at least one of the 11 tested antibiotics. The pheno- and genotyping of S. aureus isolates of sheep origin presented in this work update the epidemiological data in Slovakia.
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KAUFFMAN, N. M., and R. F. ROBERTS. "Staphylococcal Enterotoxin D Production by Staphylococcus aureus FRI 100." Journal of Food Protection 69, no. 6 (2006): 1448–51. http://dx.doi.org/10.4315/0362-028x-69.6.1448.
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Staphylococcus aureus FRI 100 is commonly used as a control strain for staphylococcal enterotoxin A (SEA) assays. When FRI 100 was used in PCR-based enterotoxin detection methods, the strain gave a positive result for both SEA and staphylococcal enterotoxin D (SED). Production of SED was confirmed by testing concentrated and unconcentrated culture supernatants with the TECRA staphylococcal enterotoxin visual immunoassay. SED was detected after 24 h of growth in Trypticase soy broth. Primers were created to amplify the entire sed gene by PCR for subsequent sequencing. The sequenced gene showed high similarity to a previously sequenced sed gene. The SED-like gene in FRI 100 exhibited four point mutations and two deletions. Changes in the FRI 100 open reading frame altered the primary structure of the SED-like protein, allowing for coding of only the first 150 amino acids followed by a stop codon. Because the SED active site is at the proximal end, where there was no change in DNA sequence, we conclude FRI 100 produces a variant form of SED. It is necessary to note that, when using FRI 100 as an SEA control strain, it does produce a variant of the SED protein, which exhibits immunological activity, and the sed-like gene is detected by commonly used PCR primers. This phenomenon may be an important general consideration when using PCR to characterize strains of toxin-producing S. aureus. S. aureus enterotoxin–positive PCR results should be confirmed by immunological techniques.
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Neelam, V. K. Jain, Mahavir Singh, et al. "Virulence and antimicrobial resistance gene profiles of Staphylococcus aureus associated with clinical mastitis in cattle." PLOS ONE 17, no. 5 (2022): e0264762. http://dx.doi.org/10.1371/journal.pone.0264762.
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Staphylococcus aureus (S. aureus) is the most prevalent microorganism associated with mastitis in cattle, which harbours several virulence factors and antibiotic resistance genes. The present study aimed to characterize S. aureus isolated from mastitic milk of the cattle for antibiotic resistance (blaZ and mecA), haemolysins (hla and hlb) and enterotoxins (sea, seb, sec, and sed) genes. A total of 69 staphylococci were isolated and phenotypically characterized for haemolytic properties on 5% sheep blood agar medium. Out of 69 isolates, 55 (79.71%) were identified as S. aureus by polymerase chain reaction assay. Among S. aureus, the majority of the isolates harboured the gene blaZ (92.73%), followed by coa (89.09%), hlb (60%) and hla (49.09%). Gene mecA responsible for methicillin resistance was detected in 23.64% of S. aureus isolates. Enterotoxin genes seb (9.09%), sec (1.82%) and sed (7.27%) responsible for food poisoning were detected at a comparatively lower rate and none of the S. aureus strain was found positive for sea. Additionally, antimicrobial susceptibility study of S. aureus against 18 antimicrobial discs showed maximum resistance to oxytetracycline, penicillin, and fluoroquinolone groups, contrarily, we observed maximum sensitivity to methicillin and cefuroxime antimicrobials. The high occurrence rate of S. aureus harbouring genes for virulence factors and antimicrobial resistance needs appropriate strategies to control the pathogen spread to the human population.
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Scatizzi, John, Argyrios Theofilopoulos, and Dwight Kono. "The role of peritoneal B-1a cells in spontaneous and induced autoimmune hemolytic anemia. (P4038)." Journal of Immunology 190, no. 1_Supplement (2013): 44.4. http://dx.doi.org/10.4049/jimmunol.190.supp.44.4.
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Abstract Previous studies have suggested peritoneal B-1a cells play a vital role in the development of anti-erythrocyte antibodies (AEA), but this remains controversial. While studying the Lbw2 lupus-susceptibility locus on chr 4, we discovered a subcongenic line, Lbw2-SE (NZB strain with 20 Mb NZW), that was deficient in peritoneal B-1a cells. NZB mice spontaneously develop autoimmune hemolytic anemia (AIHA) and exhibit an expansion of peritoneal B-1a cells, therefore we used this congenic to study the role of B-1a B cells in AEA production. Compared to NZB, Lbw2-SE mice had decreased total number of peritoneal B cell subsets (B-1a, B-1b, and B-2) but no differences in the number of splenic B cell subsets and a slight delay in AEA incidence similar to Lbw-2 congenics. To precisely map the B-1a-affecting variant, additional subcongenics were generated of which two (SEA & SED) had the low B1a phenotype. They, however, did not overlap suggesting the responsible mutation was located outside of the Lbw2-SE interval. The SEA and SED sublines had AIHA similar to NZB mice, while the SEB and SEC sublines had normal numbers of B-1a cells yet lower incidences of AIHA. Interestingly, after administering a TLR3 agonist to induce AEAs in young mice, the SEA and SED sublines with fewer B-1a cells demonstrated resistance to the development of AEAs. Our data indicate that B-1a cells are not required for the development of AEAs, but can enhance induction of AIHA under environmental conditions.
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Arslan, S., and F. Özdemir. "Molecular characterization and detection of enterotoxins, methicillin resistance genes and antimicrobial resistance of Staphylococcus aureus from fish and ground beef." Polish Journal of Veterinary Sciences 20, no. 1 (2017): 85–94. http://dx.doi.org/10.1515/pjvs-2017-0012.
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AbstractA total of 120 samples including 40 freshwaterfish(Oncorhynchus mykiss), 40 seawater fish (Sparus aurata) and 40 ground beef samples were examined for the presence of Staphylococcus aureus. The isolates were identified using biochemical tests and a PCR for the species-specific fragment (Sa442) and thermonuclease gene (nucA). The presence of staphylococcal enterotoxin genes (sea, seb, sec, sed and see), toxin genes (eta, etb, tsst), methicillin resistance gene (mecA) and some phenotypic virulence factors was also tested. Genotypic characterization of the isolates was analyzed by PCR-RFLP of the coa gene. Overall, 36 (30%) meat samples were contaminated with S. aureus. Of the 36 isolates, 3 (8.3%) were found to be positive for enterotoxin genes. Only 1 isolate (5.9%) from ground beef had the sea gene. In addition, 1 (12.5%) of the freshwater fish and 1 (9.1%) of the seawater fish carried both the sea and sed genes. The presence of seb, sec, see, eta, etb and tsst was not detected among the isolates of S. aureus. The amplified coa gene revealed five different clusters. Seven and six distinct RFLP patterns were obtained with AluI and HaeIII digestion, respectively. All isolates were found to be positive for slime, hemolytic and DNase activity while 41.7% of them were beta-lactamase positive. The presence of methicillin resistance was neither detected by PCR nor the disk diffusion method. A total of 94.4% of the isolates were resistant to at least one antimicrobial while 44.4% of them were resistant to at least two or more antimicrobials.
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Manovska, Marija Ratkova, Mirko Prodanov, Dean Jankuloski, Pavle Sekulovski, and Katerina Blagoevska. "Detection of Enterotoxigenic Potential of Staphylococcus Aureus Isolates from Cheese Samples with Two Different Methods." Macedonian Veterinary Review 45, no. 1 (2022): 27–33. http://dx.doi.org/10.2478/macvetrev-2022-0010.
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Abstract The primary objective of our study was to detect the occurrence of enterotoxigenic Staphylococcus aureus in diverse types of cheese (cow’s milk cheese and mixed milk cheese) samples from R.N. Macedonia. Cheese samples were analyzed for enumeration and isolation of the S. aureus strains according to ISO 6888-1. We detected the toxigenic potential of the strains by the use of the Enzyme Link Fluorescent Assay VIDAS system, and we confirmed the presence of the SEs (sea, seb, sec, sed, see) genes by multiplex PCR. The results showed that out of 270 samples of cheese, coagulase-positive staphylococci (CPS) were detected in 27 (10%), and coagulase-negative staphylococci in five samples (1.8%). Biochemically, all 27 CPS samples were confirmed to be Staphylococcus aureus. With VIDAS SET2 test we confirmed that 11 isolates are producers of one of the toxins limited by the test. With the conventional PCR we confirmed genes in only 7 isolates. Most common detected gene was seb n=3 (42.8%), followed by sea n=2 (28.6%), and sec n=2 (28.6%). Additionally, sed and see genes were not detected in any of the S. aureus isolates. Discrepancies between the two test methods for detection of enterotoxigenic potential are not uncommon. The presence of viable Staphylococcus aureus cells that have enterotoxin potency demonstrates the importance of appropriate hygiene practices in the diary process and also the maintenance of the products in order to obtain a safe final product for the consumers.
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Souza, Gabrielle Messias de, Mariana Francelino Almeida de Jesus, Maria Vitória de Souza Ferreira, et al. "Virulence, biofilm formation ability and antimicrobial resistance of Staphylococcus aureus isolated from cell phones of university students." ABCS Health Sciences 47 (February 14, 2022): e022203. http://dx.doi.org/10.7322/abcshs.2020154.1608.
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Introduction: Contamination of cell phones can contribute to the dissemination of pathogens in the community and/or hospital environment. Objective: To characterize Staphylococcus aureus strains isolated from cell phones of university students. Methods: Samples were collected from 100 cell phones. Detection of genes associated with virulence factors such as biofilm formation (icaA and icaD), enterotoxins production (SEA, SEB, SEC, and SED), and resistance to methicillin (mecA and mecC) was performed in S. aureus isolates by PCR. Typing mecA gene performed by multiplex PCR. Susceptibility to antimicrobials and biofilm formation rate also evaluated by using disk diffusion test and crystal violet staining. Results: S. aureus was present in 40% of the total samples and about 70% of them belonged to Nursing students. Of the isolates, 85% presented resistance to penicillin and 50% were classified as moderate biofilm producers. In addition, 92.5% of isolates contained the gene icaA and 60% of the gene icaD. Approximately 25% of the isolates presented the mecA gene. Typing of the mecA gene showed the presence of staphylococcal chromosome cassette SCCmec I and c III respectively in 20% and 10% of the isolates. 70% of the samples could not be typed by the technique. Regarding the enterotoxins, the most prevalent gene was SEA (30%) followed by the SEC gene (2.5%). The presence of SED and SEB genes not observed in any of the isolates. Conclusion: The cleaning and periodic disinfection of cell phones can contribute to the reduction of the risk of nosocomial infection.
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CHIANG, YU-CHENG, LI-TUNG CHANG, CHIA-WEI LIN, CHI-YEA YANG, and HAU-YANG TSEN. "PCR Primers for the Detection of Staphylococcal Enterotoxins K, L, and M and Survey of Staphylococcal Enterotoxin Types in Staphylococcus aureus Isolates from Food Poisoning Cases in Taiwan." Journal of Food Protection 69, no. 5 (2006): 1072–79. http://dx.doi.org/10.4315/0362-028x-69.5.1072.
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Staphylococcal enterotoxins (SEs) are important causative agents in gastroenteritidis and food poisoning cases. They are serologically grouped into five major classical types, i.e., SEA, SEB, SEC, SED, and SEE. In addition, new SEs, such as SEG through SEM, have recently been identified and characterized. In an attempt to survey the distribution of classical and new SEs in organisms responsible for staphylococcal infections in Taiwan, we developed PCR primers for the genes that define the SEK, SEL, and SEM types. Bacterial strains other than sek, sel, and sem Staphylococcus aureus, including strains of other Staphylococcus species, did not generate any false-positive results when examined with these primers. The expression potential for the sek, sel, and sem types were also determined by reverse transcription–PCR. Together with the PCR primers specific for the classical SEs and other new SEs, including SEG, SEH, SEI, and SEJ, we surveyed the SE genes in S. aureus strains isolated from food poisoning cases. For 147 S. aureus isolates originating from food poisoning cases, 109 (74.1%) were positive for one or more SE genes. Of them, the major classical enterotoxin type was sea (28.6%), followed by seb (20.4%), sec (8.2%), and sed (2.0%). For the new SE types, sei (30.6%) was detected the most often, followed by sek (18.4%), sem (12.9%), and sel (8.2%). Also, 64 (43.5%) of the total bacterial strains had more than one enterotoxin gene.
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BERNINI, VALENTINA, ELISA SGARBI, CLAUDIO GIORGIO BOVE, MONICA GATTI, and ERASMO NEVIANI. "A Polyphasic Approach To Detect Enterotoxigenic Staphylococcus aureus and Diarrheagenic Escherichia coli in Raw Milk Italian Cheeses by Multiplex PCR." Journal of Food Protection 73, no. 12 (2010): 2281–84. http://dx.doi.org/10.4315/0362-028x-73.12.2281.
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A polyphasic approach was evaluated for the detection of eight staphylococcal enterotoxin (SE)–encoding genes (sea, sec, sed, seg, seh, sei, sej, sel) and the Escherichia coli genes most commonly associated with virulence factors (eae, elt, ipaH, stx) in traditional soft cheeses, manufactured artisanally from whole raw milk in the Lombardy region (northern Italy). To determine the presence of the target genes, two multiplex PCRs were performed on DNA extracted both directly from cheese samples (culture-independent approach) and from whole cultivable cells, formed by harvesting colonies from the first serial dilution agar plates of selective media, as representative of cultivable community (“bulk”). Genes associated with enteroinvasive E. coli, ipaH, and Shiga toxin–producing E. coli, stx, were detected in two of the bulk samples analyzed; no virulence genes were found by amplifying DNA directly extracted from cheeses. SE-encoding genes were found in three cheeses (sea in all three samples, associated with sed and sej in two of these). More SE-encoding genes were detected by amplifying DNA obtained from bulk samples: sea, sed, sej, sec, seg, sel, and sei. No samples harbored the gene encoding for SE type H. The polyphasic approach followed has been useful in enhancing detection of target genes. Our results indicate that some of the artisanal cheeses examined may constitute a potential hazard for consumer health.
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Avşaroğlu, M. Dilek. "Prevalence of Staphylococcus aureus Isolated From Various Foods of Animal Origin in Kırşehir, Turkey and Their Enterotoxigenicity." Turkish Journal of Agriculture - Food Science and Technology 4, no. 12 (2016): 1179. http://dx.doi.org/10.24925/turjaf.v4i12.1179-1184.961.
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The aim of this study was to detect Staphylococcus aureus contamination to different types of animal origin foods collected in the Kırşehir province of Turkey and to examine their enterotoxin production ability. Out of 120 food samples 38 suspected colonies were obtained and 23 of them were identified as S. aureus by biochemical and molecular analyses. Other species detected were S. chromogenes, S. cohnii ssp. cohnii, S. hominis, S. lentus, S. warneri, and S. xylosus. The isolates were also analysed with regard to carry mecA gene. None of them was found to have mecA gene indicating susceptibility to methicillin. To determine the enterotoxigenic ability of the isolates phenotypically, reversed-passive-latex-agglutination test against SEA-SED was used. Six out of 23 S. aureus isolates were determined to produce SEA, SEC and SED. Three of them had only one enterotoxin production, whereas others had SEA and SED production together. The results of phenotypic analyses were confirmed by PCR based examination. None of the coagulase-negative staphylococci were found to be enterotoxigenic by both phenotypical and PCR-based analyses. In conclusion, enterotoxigenic S. aureus is a risk in foods of animal origin in Kırşehir and its counties.
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Johler, Sophia, Henna-Maria Sihto, Guerrino Macori, and Roger Stephan. "Sequence Variability in Staphylococcal Enterotoxin Genes seb, sec, and sed." Toxins 8, no. 6 (2016): 169. http://dx.doi.org/10.3390/toxins8060169.
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Chintagumpala, M. M., J. A. Mollick, and R. R. Rich. "Staphylococcal toxins bind to different sites on HLA-DR." Journal of Immunology 147, no. 11 (1991): 3876–81. http://dx.doi.org/10.4049/jimmunol.147.11.3876.
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Abstract Staphylococcal enterotoxins (SE) and toxic shock syndrome toxin 1 (TSST-1) bind to MHC class II molecules and the toxin-class II complexes induce proliferation of T cells bearing specific V beta sequences. We have previously reported that these toxins display varying binding affinities for HLA-DR1. We now investigated whether these differences simply reflected differences in binding affinity for a single class II binding site or, at least in part, the engagement of different binding sites on the HLA-DR complex. Through competitive binding studies we show that SEB and TSST-1, which are not closely related by their amino acid sequences, bind to two different sites on HLA-DR. Both of these sites are also occupied by staphylococcal enterotoxin A (SEA), enterotoxin D (SED), and enterotoxin E (SEE) which exhibit more than 70% amino acid sequence homology. SEB and TSST-1 failed to inhibit SEA binding to HLA-DR. These studies suggest that there may be three distinct, although perhaps overlapping, binding sites on HLA-DR for these toxins. Further, although SED and SEE are similar to SEA in structure, and appear to bind the same sites on HLA-DR as SEA, they displayed significantly lower binding affinities. T cell proliferative responses to SED required a higher concentration of the toxin than SEA, probably reflecting its lower binding affinity. SEE, however, elicited T cell responses at very low concentrations, similar to SEA, despite its much lower binding affinity. Therefore, although the affinities of these toxins to MHC class II molecules appear to significantly influence the T cell responses, the effective recognition of the toxin-class II complex by the TCR may also contribute to such responses.
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Frederikse, Thomas, Felix W. Landerer, and Lambert Caron. "The imprints of contemporary mass redistribution on local sea level and vertical land motion observations." Solid Earth 10, no. 6 (2019): 1971–87. http://dx.doi.org/10.5194/se-10-1971-2019.
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Abstract. Observations from permanent Global Navigation Satellite System (GNSS) stations are commonly used to correct tide-gauge observations for vertical land motion (VLM). We combine GRACE (Gravity Recovery and Climate Experiment) observations and an ensemble of glacial isostatic adjustment (GIA) predictions to assess and evaluate the impact of solid-Earth deformation (SED) due to contemporary mass redistribution and GIA on VLM trends derived from GNSS stations. This mass redistribution causes relative sea-level (RSL) and SED patterns that not only vary in space but also exhibit large interannual variability signals. We find that for many stations, including stations in coastal locations, this deformation causes VLM trends on the order of 1 mm yr−1 or higher. In multiple regions, including the Amazon Basin and large parts of Australia, the SED trend flips sign between the first half and second half of the 15-year GRACE record. GNSS records often only span a few years, and due to these interannual variations SED causes substantial biases when the linear trends in these short records are extrapolated back in time. We propose a new method to avoid this potential bias in the VLM-corrected tide-gauge record: instead of correcting tide-gauge records for the observed VLM trend, we first remove the effects from GIA and contemporary mass redistributions from the VLM observations before computing the VLM trend. This procedure reduces the extrapolation bias induced by SED, and it also avoids the bias due to sea-floor deformation: SED includes net sea-floor deformation, which is ignored in global-mean sea-level reconstructions based on VLM-corrected tide-gauge data. We apply this method to 8166 GNSS stations. With this separation, we are able to explain a large fraction of the discrepancy between observed sea-level trends at multiple long tide-gauge records and the global-mean sea-level trend from recent reconstructions.
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Homsombat, Theeyathart, Sukolrat Boonyayatra, Nattakarn Awaiwanont, and Duangporn Pichpol. "Effect of Temperature on the Expression of Classical Enterotoxin Genes among Staphylococci Associated with Bovine Mastitis." Pathogens 10, no. 8 (2021): 975. http://dx.doi.org/10.3390/pathogens10080975.
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Staphylococcal food poisoning (SFP), caused by the contamination of staphylococcal enterotoxins, is a common foodborne disease worldwide. The aims of this study were: (1) to investigate classical staphylococcal enterotoxin genes, sea, seb, sec, sed, and see, among Staphylococcus aureus and coagulase-negative staphylococci (CNS) associated with bovine mastitis; (2) to determine the effect of temperature on the expression of classical staphylococcal enterotoxin genes in staphylococci in milk. The detection of classical staphylococcal enterotoxin genes was performed using S. aureus (n = 51) and CNS (n = 47). The expression of classical enterotoxin genes, including sea, seb, sec, and see, was determined during the growth of staphylococci in milk subjected to ultra-high-temperature processing at two different temperatures: 8 °C and room temperature. Classical staphylococcal enterotoxin genes were expressed more frequently in S. aureus (35.30%) than in CNS (12.77%). The sec gene was most frequently detected in S. aureus (29.41%) and CNS (6.38%). Moreover, the expression of sea and sec was significantly higher at room temperature than at 8 °C after 16 h of incubation (p < 0.05). These results emphasize the importance of maintaining the storage temperature of milk below 8 °C to reduce the risk of SFP.
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Sura I. A. Jabuk and Eman M. Jarallah. "Molecular screening of Staphylococcus aureus enterotoxins associated with samples of meat / Iraq." International Journal of Research in Pharmaceutical Sciences 11, no. 4 (2020): 6685–91. http://dx.doi.org/10.26452/ijrps.v11i4.3590.
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Staphylococcus aureus secreted many types of toxins accompanying Intestinal poisoning resulting from eating food contaminated with bacteria or their toxins. Five hundred meat samples were collected from local markets, including fresh, frozen, canned, sausage and hamburger to investigate their contamination with S.aureus and then determined their ability of these isolates to secrete enterotoxins by using polymerase chain reaction. The results showed that the ratio of isolated S.aureus is 30 (6%) and the percentage of encoding genes for toxins is 30(100%), 0(0%), 3(10), 0(0%),0(0%),3(10), 2(6.7), 1(3.3), 0(0%) and 3(10) to sea, seb, sec, sed, see, seg, see, sei, sej and sel respectively.The result shows the S.aureus isolated from contamination meat able to produce different type to enterotoxins sea, sec, seg, see, sei, and sel and present the sea toxin is the most prevalence type of staphylococcus enterotoxins.
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Uzeh, R. E., S. A. Adesida, and A. O. Adedokun. "Classical Enterotoxin Genes Carriage among Staphylococcus aureus from Food Handlers in a Nigerian University Community." Acta Microbiologica Bulgarica 39, no. 4 (2023): 428–35. http://dx.doi.org/10.59393/amb23390410.
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Enterotoxigenic Staphylococcus aureus is one of the major causes of food poisoning due to asymp¬tomatic carriage. This study aimed to determine the presence of S. aureus in the nasal cavities and hands of food handlers in a university setting in Nigeria. It also assessed their susceptibility to antibiotics and examined the carriage of classical enterotoxin genes. Swab samples (120) collected from the anterior nar¬es and hands of 40 food handlers were screened for S. aureus using standard microbiological methods. Susceptibility testing for cefoxitin, ciprofloxacin, and vancomycin was performed using the disk diffusion method. Staphylococcal enterotoxin (sea - sed) genes were detected by multiplex PCR. A total of 34 S. aureus isolates were identified, with 12 from the nares, 12 from the right hand, and 10 from the left hand. Ciprofloxacin resistance was found in 55.9% of the isolates, cefoxitin resistance was 32.4%, and none was susceptible to vancomycin. The sec gene was the most prominent, accounting for 26.5% of all enterotox¬in genes identified. No isolates harbored the seb gene but a nasal methicillin-susceptible S. aureus strain from one of the food handlers harbored three enterotoxin genes (sec, sed, see) simultaneously. Three (3) sec-carrying strains were resistant to the three antibiotics tested. The study revealed a substantial proportion of carriers of classical enterotoxin genes among the food handlers examined. It also showed resistance to antibiotics relevant to the management of staphylococcal infections. These strains could spread through the community.
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Chen, Yu, Xiangqian Zhang, Jing Yang, et al. "Extracellular Vesicles Derived from Selenium-Deficient MAC-T Cells Aggravated Inflammation and Apoptosis by Triggering the Endoplasmic Reticulum (ER) Stress/PI3K-AKT-mTOR Pathway in Bovine Mammary Epithelial Cells." Antioxidants 12, no. 12 (2023): 2077. http://dx.doi.org/10.3390/antiox12122077.
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Selenium (Se) deficiency disrupts intracellular REDOX homeostasis and severely deteriorates immune and anti-inflammatory function in high-yielding periparturient dairy cattle. To investigate the damage of extracellular vesicles derived from Se-deficient MAC-T cells (SeD-EV) on normal mammary epithelial cells, an in vitro model of Se deficiency was established. Se-deficient MAC-T cells produced many ROS, promoting apoptosis and the release of inflammatory factors. Extracellular vesicles were successfully isolated by ultrahigh-speed centrifugation and identified by transmission electron microscopy, particle size analysis, and surface markers (CD63, CD81, HSP70, and TSG101). RNA sequencing was performed on exosomal RNA. A total of 9393 lncRNAs and 63,155 mRNAs transcripts were identified in the SeC and SeD groups, respectively, of which 126 lncRNAs and 955 mRNAs were differentially expressed. Furthermore, SeD-EV promoted apoptosis of normal MAC-T cells by TUNEL analysis. SeD-EV significantly inhibited Bcl-2, while Bax and Cleaved Caspase3 were greatly increased. Antioxidant capacity (CAT, T-AOC, SOD, and GSH-Px) was inhibited in SeD-EV-treated MAC-T cells. Additionally, p-PERK, p-eIF2α, ATF4, CHOP, and XBP1 were all elevated in MAC-T cells supplemented with SeD-EV. In addition, p-PI3K, p-Akt, and p-mTOR were decreased strikingly by SeD-EV. In conclusion, SeD-EV caused oxidative stress, thus triggering apoptosis and inflammation through endoplasmic reticulum stress and the PI3K-Akt-mTOR signaling pathway, which contributed to explaining the mechanism of Se deficiency causing mastitis.
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Saleh, Dennis. "The Sed." Psychological Perspectives 61, no. 3 (2018): 394–96. http://dx.doi.org/10.1080/00332925.2018.1496713.
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Tassara, Axel. "La Sed." ÍSTMICA. Revista de la Facultad de Filosofía y Letras, no. 21 (June 19, 2018): 89. http://dx.doi.org/10.15359/istmica.21.6.
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Stierle, Karlheinz, and Carsten Dutt. "SED CONTRA." German Quarterly 87, no. 1 (2014): 1–16. http://dx.doi.org/10.1111/gequ.10194.
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Wellbery, David E., and Carsten Dutt. "SED CONTRA." German Quarterly 87, no. 3 (2014): 257–76. http://dx.doi.org/10.1111/gequ.10209.
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Teichert, Dieter, and Carsten Dutt. "SED CONTRA." German Quarterly 88, no. 4 (2015): 421–50. http://dx.doi.org/10.1111/gequ.10243.
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Prado, Ignacio M. Sánchez, and Adriana Díaz Enciso. "La sed." Chasqui 31, no. 1 (2002): 115. http://dx.doi.org/10.2307/29741734.
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Culling, W. E. "Sed contra." CATENA 14, no. 1-3 (1987): 146–47. http://dx.doi.org/10.1016/s0341-8162(87)80012-7.
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Ollier, C. D., and R. W. Galloway. "Sed contra." CATENA 18, no. 6 (1991): 589–90. http://dx.doi.org/10.1016/0341-8162(91)90042-v.
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Crook, Keith, Andrew Miall, and Bruce W. Sellwood. "Sed-Century." Sedimentary Geology 100, no. 1-4 (1995): 1–3. http://dx.doi.org/10.1016/0037-0738(95)00099-2.
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Costa, Juliana de Castro Beltrão da, Elaine Ibrahim de Freitas, Anderson Almeida de Lemos, et al. "Isolamento de Staphylococcus de queijo minas frescal e detecção de genes de enterotoxinas." Revista do Instituto Adolfo Lutz 71, no. 2 (2012): 250–58. http://dx.doi.org/10.53393/rial.2012.v71.32422.
Full textAbstract:
Neste trabalho foi realizado o isolamento de Staphylococcus spp. de queijo minas frescal, e para esta finalidade foi padronizado um protocolo multiplex PCR (M-PCR) para efetuar a detecção de genes de enterotoxinas clássicas (sea, seb, sec, sed e see) de Staphylococcus aureus, usando-se o gene femA como controle positivo para cepas de S. aureus. Foi testada a detecção direta de bactérias de amostras de queijo minas frescal e do alimento artificialmente contaminado. Cento e onze colônias (104 coagulase-positivas e sete coagulase-negativas) foram selecionadas e analisadas por M-PCR e, dentre essas, 34 colônias (30.62%) foram positivas para pelo menos um dos cinco genes de enterotoxinas analisados. Os genes que codificam as enterotoxinas sea e seb foram os mais frequentemente detectados. O estudo de isolamento de estafilococos coagulase-positivos revelaram que 40% das amostras demonstraram contagens bacterianas acima do limite considerado como aceitável pela legislação brasileira.
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Schelin, Jenny, Marianne Thorup Cohn, Barbro Frisk, and Dorte Frees. "A Functional ClpXP Protease is Required for Induction of the Accessory Toxin Genes, tst, sed, and sec." Toxins 12, no. 9 (2020): 553. http://dx.doi.org/10.3390/toxins12090553.
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Staphylococcal toxic shock syndrome is a potentially lethal illness attributed to superantigens produced by Staphylococcus aureus, in particular toxic shock syndrome toxin 1 (TSST-1), but staphylococcal enterotoxins (SEs) are also implicated. The genes encoding these important toxins are carried on mobile genetic elements, and the regulatory networks controlling expression of these toxins remain relatively unexplored. We show here that the highly conserved ClpXP protease stimulates transcription of tst (TSST-1), sec (SEC), and sed (SED) genes in the prototypical strains, SA564 and RN4282. In the wild-type cells, the post-exponential upregulation of toxin gene transcription was proposed to occur via RNAIII-mediated downregulation of the Rot repressor. Contradictive to this model, we showed that the post-exponential induction of tst, sed, and sec transcription did not occur in cells devoid of ClpXP activity, despite the Rot level being diminished. To identify transcriptional regulators with a changed expression in cells devoid of ClpXP activity, RNA sequencing was performed. The RNAseq analysis revealed a number of global virulence regulators that might act downstream of ClpXP, to control expression of tst and other virulence genes. Collectively, the results extend our understanding of the complex transcriptional regulation of the tst, sed, and sec genes.
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Tseng, Ching Wen, Shuping Zhang, and George C. Stewart. "Accessory Gene Regulator Control of Staphyloccoccal Enterotoxin D Gene Expression." Journal of Bacteriology 186, no. 6 (2004): 1793–801. http://dx.doi.org/10.1128/jb.186.6.1793-1801.2004.
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ABSTRACT The quorum-sensing system of Staphylococcus aureus, the accessory gene regulator (Agr) system, is responsible for increased transcription of certain exoprotein genes and decreased transcription of certain cell wall-associated proteins during the postexponential phase of growth. This regulation is important for virulence, as evidenced by a reduction in virulence associated with a loss of the Agr system. The enterotoxin D (sed) determinant is upregulated by the Agr system. To define the Agr-regulated cis element(s) within the sed promoter region, we utilized promoters not regulated by Agr to create hybrid promoters. Hybrid promoters were created by using sed sequences combined with the enterotoxin A (sea) promoter or the S. aureus lac operon promoter sequences. The results obtained indicated that the Agr control element of the sed promoter resides within the −35 promoter element and at the Pribnow box to the +1 site of the promoter. At these positions of the sed promoter, a directly repeated 6-bp sequence was found. This repeat is important for overall promoter activity, and maximal regulation of the promoter activity requires both repeat elements. Furthermore, Agr control of sed promoter activity was found to be dependent upon the presence of a functional Rot protein. Therefore, the postexponential increase in sed transcription results from the Agr-mediated reduction in Rot activity rather than as a direct effect of the Agr system.