RESUMEN

Staphylococcal enterotoxins are one of the most important causative agents of food poisoning. These molecules function as both gastrointestinal toxins and superantigens (SAgs) which can simultaneously bind MHC-II and T cell receptor leading to a non-specific polyclonal T cell activation and massive proinflammatory cytokine release. Common symptoms include vomiting and diarrhea; however, in more severe cases, systemic dissemination may result in toxic shock syndrome and can be lethal in a few hours. Only small amounts of these heat-stable toxins are needed to cause the disease. Therefore, it is highly important to detect quickly low concentrations of SAgs in biological samples. In this work, we report a surface plasmon resonance (SPR)-based capture immunoassay for the detection of the SAg SEG. We analyzed the use of different amplification strategies. The SPR-based double-antibody sandwich approach could detect picomolar levels of SEG. The use of antibody-coated silica nanoparticles (AbSiNPs) as an alternative enhancing reagent also detected SEG in the picomolar range. Although AbSiNPs did not improve the limit of detection, for the same amount of SAg tested, AbSiNPs gave a higher response level than free antibodies. This work highlights the suitability of silica nanoparticles for signal amplification in SPR-based biosensors. Overall, SPR biosensors offer the capability for continuous real-time monitoring and high sensitivity that can be befitting for the detection of enterotoxins in food industries, laboratories and regulatory agencies.

Asunto(s)

Enterotoxinas/análisis , Inmunoensayo/métodos , Superantígenos/análisis , Resonancia por Plasmón de Superficie/métodos , Secuencia de Aminoácidos , Animales , Anticuerpos Antibacterianos , Técnicas Biosensibles/métodos , Materiales Biocompatibles Revestidos , Enterotoxinas/genética , Enterotoxinas/inmunología , Microbiología de Alimentos , Humanos , Límite de Detección , Nanopartículas , Conejos , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Dióxido de Silicio , Intoxicación Alimentaria Estafilocócica/diagnóstico , Staphylococcus aureus/química , Staphylococcus aureus/genética , Staphylococcus aureus/inmunología , Superantígenos/genética , Superantígenos/inmunología

RESUMEN

Chagas disease is an endemic chronic parasitosis in Latin America affecting more than 7 million people. Around 100 million people are currently at risk of acquiring the infection; however, no effective vaccine has been developed yet. Trypanosoma cruzi is the etiological agent of this parasitosis and as an intracellular protozoan it can reside within different tissues, mainly muscle cells, evading host immunity and allowing progression towards the chronic stage of the disease. Considering this intracellular parasitism triggers strong cellular immunity that, besides being necessary to limit infection, is not sufficient to eradicate the parasite from tissues, a differential immune response is required and new strategies for vaccines against Chagas disease need to be explored. In this work, we designed, cloned and expressed a chimeric molecule, named NCz-SEGN24A, comprising a parasite antigen, the N-terminal domain of the major cysteine protease of T. cruzi, cruzipain (Nt-Cz), and a non-toxic form of the staphylococcal superantigen (SAg) G, SEG, with the residue Asn24 mutated to Ala (N24A). The mutant SAg SEGN24A, retains its ability to trigger classical activation of macrophages without inducing T cell apoptosis. To evaluate, as a proof of concept, the immunogenicity and efficacy of the chimeric immunogen vs. its individual antigens, C3H mice were immunized intramuscularly with NCz-SEGN24A co-adjuvanted with CpG-ODN, or the recombinant proteins Nt-Cz plus SEGN24A with the same adjuvant. Vaccinated mice significantly produced Nt-Cz-specific IgG titers after immunization and developed higher IgG2a than IgG1 titers. Specific cell-mediated immunity was assessed by in-vivo DTH and significant responses were obtained. To assess protection, mice were challenged with trypomastigotes of T. cruzi. Both schemes reduced the parasite load throughout the acute phase, but only mice immunized with NCz-SEGN24A showed significant differences against control; moreover, these mice maintained 100% survival. These results encourage testing mutated superantigens fused to specific antigens as immune modulators against pathogens.

Asunto(s)

Antígenos Bacterianos/inmunología , Enfermedad de Chagas/prevención & control , Protección Cruzada/inmunología , Cisteína Endopeptidasas/inmunología , Proteínas Protozoarias/inmunología , Superantígenos/inmunología , Trypanosoma cruzi/inmunología , Animales , Anticuerpos Neutralizantes , Anticuerpos Antiprotozoarios/inmunología , Antígenos Bacterianos/química , Antígenos Bacterianos/genética , Antígenos de Protozoos/inmunología , Enfermedad de Chagas/inmunología , Enfermedad de Chagas/parasitología , Cisteína Endopeptidasas/genética , Modelos Animales de Enfermedad , Inmunidad Celular , Inmunidad Humoral , Inmunización , Ratones , Carga de Parásitos , Conformación Proteica , Dominios Proteicos/inmunología , Proteínas Protozoarias/genética , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Superantígenos/química , Superantígenos/genética , Linfocitos T/inmunología , Linfocitos T/metabolismo

RESUMEN

Staphylococcus aureus is one of the main pathogens found in cheeses produced with raw milk, including Minas artisanal cheese from Brazil. However, information about S. aureus isolated from artisanal cheeses and its sources of production in small-scale dairies is very limited. We aimed to characterize the virulence factors of S. aureus isolated from raw milk, endogenous starter culture, Minas artisanal cheese, and cheese handlers from the region of Campo das Vertentes, Minas Gerais, Brazil. We identified the staphylococcal isolates by MALDI-TOF mass spectrometry. We evaluated biofilm production on Congo red agar and polystyrene plates. We used PCR to detect icaA, icaB, icaC, sea, seb, sec, sed, see, tsst-1, agr, and mecA. We evaluated the expression of staphylococcal toxin genes in PCR-positive staphylococcal isolates using quantitative reverse-transcription PCR, and we evaluated the production of these toxins and their hemolytic activity in vitro. We also evaluated the antimicrobial resistance profile of the staphylococcal isolates. For statistical analysis, we used cluster analysis, χ2 tests, and correspondence tests. We analyzed 76 staphylococcal isolates. According to PCR, 18.42, 18.42, 2.63, and 77.63% were positive for sea, tsst-1, sec, and agr, respectively. We found low expression of staphylococcal toxin genes according to quantitative reverse-transcription PCR, and only 2 staphylococcal isolates produced toxic shock syndrome toxins. A total of 43 staphylococcal isolates (56.58%) had hemolytic activity; 53 were biofilm-forming on Congo red agar (69.73%), and 62 on polystyrene plates (81.58%). None of the staphylococcal isolates expressed the mecA gene, and none presented a multi-drug resistance pattern. The highest resistance was observed for penicillin G (67.11%) in 51 isolates and for tetracycline (27.63%) in 21 isolates. The staphylococcal isolates we evaluated had toxigenic potential, with a higher prevalence of sea and tsst-1. Biofilm production was the main virulence factor of the studied bacteria. Six clusters were formed whose distribution frequencies differed for hemolytic activity, biofilm formation (qualitative and quantitative analyses), and resistance to penicillin, tetracycline, and erythromycin. These findings emphasize the need for effective measures to prevent staphylococcal food poisoning by limiting S. aureus growth and enterotoxin formation throughout the food production chain and the final product.

Asunto(s)

Biopelículas/crecimiento & desarrollo , Queso/microbiología , Farmacorresistencia Bacteriana , Choque Séptico/microbiología , Intoxicación Alimentaria Estafilocócica/microbiología , Staphylococcus aureus/genética , Factores de Virulencia , Animales , Antibacterianos/farmacología , Toxinas Bacterianas/genética , Brasil , Enterotoxinas/genética , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/patogenicidad , Superantígenos/genética

RESUMEN

Bovine mastitis affects dairy cattle worldwide and Staphylococcus aureus is one of the most common microorganisms involved in subclinical and chronic disease. Superantigens, such as enterotoxins contribute to S. aureus persistence and pathogenicity in this disease. Subclinical and chronic mastitis cases were diagnosed and S. aureus isolates from sub-clinical cases were investigated for carriage of virulence and antibiotic resistance genes that may contribute to long-term carriage and infection. Over a 12-month period, 116 S. aureus strains were recovered from 68 cows with subclinical mastitis. Classical enterotoxin genes (sea-see) were detected in 24.1% of isolates, and pvl and tsst-1 were identified in 3.4% and 46.6% the isolates, respectively. 18.1% that were persistent isolates were identified and characterized by pulsed field gel electrophoresis (PFGE), MLST, spa typing. Four isolates were methicillin-resistant S. aureus (MRSA) and belonged to SCCmec type I. Molecular typing showed that the agrI group was the most frequent, and a rare isolate was positive for both agrI and agrIII groups. Molecular characterization revealed the persistence of the spa type t10856 (ST133, clonal complex CC133, agr I), in a single animal for nine months and the persistence t605 (ST126, CC126) colonizing four animals for four months. These strains have been described recently in other herds in the same region, indicating their transmissibility and clonal expansion. We conclude that animals with subclinical mastitis are an important and somewhat overlooked reservoir for transmission within and between herds, and may carry virulence and antibiotic resistance genes contributing to persistent colonization, hinder the control of mastitis and may cause risks to the public health.

Asunto(s)

Genotipo , Mastitis Bovina/microbiología , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidad , Animales , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Bovinos , ADN Bacteriano , Electroforesis en Gel de Campo Pulsado , Enterotoxinas/genética , Exotoxinas/genética , Femenino , Leucocidinas/genética , Staphylococcus aureus Resistente a Meticilina/genética , Pruebas de Sensibilidad Microbiana , Leche/microbiología , Tipificación Molecular/métodos , Tipificación de Secuencias Multilocus , Staphylococcus aureus/aislamiento & purificación , Superantígenos/genética , Transactivadores/genética , Virulencia/genética , Factores de Virulencia/genética

RESUMEN

Bacterial superantigens (SAgs) are enterotoxins that bind to MHC-II and TCR molecules, activating as much as 20% of the T cell population and promoting a cytokine storm which enhances susceptibility to endotoxic shock, causing immunosuppression, and hindering the immune response against bacterial infection. Since monocytes/macrophages are one of the first cells SAgs find in infected host and considering the effect these cells have on directing the immune response, here, we investigated the effect of four non-classical SAgs of the staphylococcal egc operon, namely, SEG, SEI, SEO, and SEM on monocytic-macrophagic cells, in the absence of T cells. We also analyzed the molecular targets on APCs which could mediate SAg effects. We found that egc SAgs depleted the pool of innate immune effector cells and induced an inefficient activation of monocytic-macrophagic cells, driving the immune response to an impaired proinflammatory profile, which could be mediated directly or indirectly by interactions with MHC class II. In addition, performing surface plasmon resonance assays, we demonstrated that non-classical SAgs bind the gp130 molecule, which is also present in the monocytic cell surface, among other cells.

Asunto(s)

Antígenos Bacterianos/inmunología , Macrófagos/inmunología , Monocitos/inmunología , Infecciones Estafilocócicas/inmunología , Staphylococcus aureus/inmunología , Superantígenos/inmunología , Animales , Antígenos Bacterianos/genética , Muerte Celular , Antígenos de Histocompatibilidad Clase II/genética , Antígenos de Histocompatibilidad Clase II/inmunología , Humanos , Macrófagos/citología , Ratones , Ratones Endogámicos BALB C , Monocitos/citología , Operón , Infecciones Estafilocócicas/genética , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/fisiopatología , Staphylococcus aureus/genética , Superantígenos/genética

RESUMEN

AIMS: To determine the virulence and antimicrobial resistant genes in methicillin resistant Staphylococcus aureus isolates recovered from patients attending two rural health centers in Trinidad and Tobago. SETTINGS AND DESIGN: Cross-sectional observational analysis of patients from two local health centers located in communities in northern region of the country. MATERIALS AND METHODS: Nasal and wound swabs from 300 patients were analyzed using standard and molecular techniques. Multiplex polymerase chain reaction was used to detect 16S rRNA, mec A, Staphylococcal chromosomal cassette SCC mec types, pvl, alpha hemolysin (hla), and Toxic Shock Syndrome Toxin 1 (tst 1) genes. S. aureus ATCC 33591 and Staphylococcus epidermidis ATCC 12228 were used for quality control, respectively. RESULTS: Over a quarter (26.7%, 80/300) of the surveyed patient's samples grew bacterial isolates of which 45% (36/80) were S. aureus and 44.4% (16/36) were mecA-positive. Majority (62.5%, 10/16) possessed the pvl gene, whereas 25% (4/16) possessed the alpha hemolysin (hla) gene. None of the methicillin-resistant Staphylococcus aureus (MRSA) isolates possessed the tst 1 gene. Also, 18.8% (3/16) isolates possessed both virulence genes, pvl and hla. Although the SCCmec types IV and V were detected, but none of the SCCmec I, II, and III were harbored by the isolates. CONCLUSIONS: SCCmec type IV and the pvl genes were common among the MRSA isolates from the community. The hla gene was found infrequently, but none of the isolates possessed the tst 1 gene. Knowledge of this is important for robust surveillance of such cases from the community in the country.

Asunto(s)

Antibacterianos/farmacología , Toxinas Bacterianas/genética , Enterotoxinas/genética , Exotoxinas/genética , Proteínas Hemolisinas/genética , Leucocidinas/genética , Staphylococcus aureus Resistente a Meticilina/genética , Meticilina/farmacología , Nariz/microbiología , Superantígenos/genética , Estudios Transversales , Humanos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S , Población Rural , Staphylococcus aureus , Trinidad y Tobago

RESUMEN

Introducción. Staphylococcus aureus coloniza mucosas y piel, y causa graves infecciones en el hombre y los animales. Es importante establecer el estatus de portadoras de cepas enterotoxigénicas de este microorganismo en manipuladoras de alimentos, con el fin de prevenir intoxicaciones alimentarias.Objetivo. Establecer las correlaciones entre los genes de enterotoxinas clásicas, el gen tsst-1, la producción de toxinas en cultivo y la resistencia antimicrobiana en aislamientos de S. aureus provenientes de manipuladoras de alimentos que cuidan niños en sus comunidades.Materiales y métodos. Se cultivaron muestras de las fosas nasales y las yemas de los dedos de las manos, y se identificó S. aureus empleando las pruebas de rutina y métodos automatizados. La extracción de ADN se hizo mediante el método de bromuro de cetil-trimetil-amonio (Cetyl-Trimethyl-Ammonium Bromide, CTAB) modificado. Para la detección de superantígenos se emplearon pruebas de reacción en cadena de la polimerasa (PCR) simple y múltiple, y para la de toxinas, estuches comerciales.Resultados. Se encontró que el 22,0 % de los aislamientos correspondía a portadoras de S. aureus: 17,0 % en los aislamientos de fosas nasales; 5,0 % en los de las manos y 6,7 % simultáneamente en los dos sitios. La prevalencia de superantígenos fue de 73,7 %. El genotipo más frecuente fue el seatsst-1, con 10,0 %. La resistencia a un solo antibiótico fue de 74,7 % y, a cuatro antibióticos, de 3,2 %; de los aislamientos, el 93,7 % correspondía a cepas productoras de betalactamasas. La detección de genes clásicos y de tsst-1 mediante PCR fue de 48,4 % y la de toxinas en el sobrenadante, de 42,1 %,con una correlación de 95,7 %. Las mayores correlaciones se establecieron entre las toxinas TSST-1 (22/22) y SEA (17/18). La correlación del gen tsst-1 con la proteína y la resistencia fue de 100 %. Todos los aislamientos con el genotipo sea-tsst-1 t fueron resistentes y productores de las toxinas.Conclusión. La tasa de aislamientos de S. aureus toxigénicos y resistentes obtenidos de mujeres que cuidan y preparan alimentos para niños fue de más de 70 %, lo que demostró su gran virulencia y la consecuente necesidad de aplicar estrictamente las normas higiénicas y sanitarias vigentes para evitar el riesgo de intoxicación alimentaria.

Asunto(s)

Antígenos Bacterianos/análisis , Portador Sano/microbiología , Cuidado del Niño , Farmacorresistencia Bacteriana Múltiple , Enterotoxinas/inmunología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificación , Superantígenos/análisis , Adulto , Antígenos Bacterianos/genética , Portador Sano/epidemiología , Niño , Femenino , Dedos/microbiología , Manipulación de Alimentos , Genes Bacterianos , Genotipo , Humanos , Cavidad Nasal/microbiología , Prevalencia , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/transmisión , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/inmunología , Superantígenos/genética

RESUMEN

Resumen Introducción. Staphylococcus aureus coloniza mucosas y piel, y causa graves infecciones en el hombre y los animales. Es importante establecer el estatus de portadoras de cepas enterotoxigénicas de este microorganismo en manipuladoras de alimentos, con el fin de prevenir intoxicaciones alimentarias. Objetivo. Establecer las correlaciones entre los genes de enterotoxinas clásicas, el gen tsst-1, la producción de toxinas en cultivo y la resistencia antimicrobiana en aislamientos de S. aureus provenientes de manipuladoras de alimentos que cuidan niños en sus comunidades. Materiales y métodos. Se cultivaron muestras de las fosas nasales y las yemas de los dedos de las manos, y se identificó S. aureus empleando las pruebas de rutina y métodos automatizados. La extracción de ADN se hizo mediante el método de bromuro de cetil-trimetil-amonio (Cetyl-Trimethyl- Ammonium Bromide, CTAB) modificado. Para la detección de superantígenos se emplearon pruebas de reacción en cadena de la polimerasa (PCR) simple y múltiple, y para la de toxinas, estuches comerciales. Resultados. Se encontró que el 22,0 % de los aislamientos correspondía a portadoras de S. aureus: 17,0 % en los aislamientos de fosas nasales; 5,0 % en los de las manos y 6,7 % simultáneamente en los dos sitios. La prevalencia de superantígenos fue de 73,7 %. El genotipo más frecuente fue el sea-tsst-1, con 10,0 %. La resistencia a un solo antibiótico fue de 74,7 % y, a cuatro antibióticos, de 3,2 %; de los aislamientos, el 93,7 % correspondía a cepas productoras de betalactamasas. La detección de genes clásicos y de tsst-1 mediante PCR fue de 48,4 % y la de toxinas en el sobrenadante, de 42,1 %, con una correlación de 95,7 %. Las mayores correlaciones se establecieron entre las toxinas TSST-1 (22/22) y SEA (17/18). La correlación del gen tsst-1 con la proteína y la resistencia fue de 100 %. Todos los aislamientos con el genotipo sea-tsst-1 t fueron resistentes y productores de las toxinas. Conclusión. La tasa de aislamientos de S. aureus toxigénicos y resistentes obtenidos de mujeres que cuidan y preparan alimentos para niños fue de más de 70 %, lo que demostró su gran virulencia y la consecuente necesidad de aplicar estrictamente las normas higiénicas y sanitarias vigentes para evitar el riesgo de intoxicación alimentaria.

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Abstract Introduction: Staphylococcus aureus colonizes mucous membranes and skin causing severe infections in humans and animals. It is important to determine carrier status of enterotoxigenic strains of this microorganism in food handlers to prevent food poisoning. Objective: To establish the correlations among classic enterotoxigenic genes, tsst-1 gene, the production of toxins in cultures and antimicrobial resistance in S. aureus isolates from women who handle the food, feed and take care of children in their communities. Materials and methods: Nasal swab and finger samples were cultured and S. aureus was identified using routine methods and automated systems. DNA extraction was done by the CTAB modified method, and superantigen detection by simple and multiplex PCR, while toxins were detected using commercial kits. Results: We found that 22.0% of subjects were S. aureus carriers: 17.0% corresponded to nose samples, 5.0% to hands and 6.7% to both nose and hands. The prevalence of superantigens was 73.7%. The most frequent genotype was sea-tsst-1 with 10%. Resistance to one antibiotic was 74.7%, and to four antibiotics, 3.2%; 93.7% of the isolates were betalactamase-positive. Classical genes and tsst-1 gene were detected by PCR in 48.4% of samples and toxins in supernatant were detected in 42.1% of them with 95.7% of correlation.The highest correlations were established for TSST-1 and SEA with 100% and 94.4%, respectively. The correlation of tsst-1 gene with toxin production and resistance was 100%. All isolates with genotype sea-tsst-1 were toxin-positive and resistant. Conclusion: The rate of toxigenic and resistant S. aureus isolates from women in charge of feeding and taking care of children was higher than 70%, which demonstrates its high virulence. This requires the strict application of hygienic and sanitary regulations in order to avoid the risk of food poisoning.

Asunto(s)

Adulto , Niño , Femenino , Humanos , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificación , Portador Sano/microbiología , Cuidado del Niño , Superantígenos/análisis , Farmacorresistencia Bacteriana Múltiple , Enterotoxinas/inmunología , Antígenos Bacterianos/análisis , Infecciones Estafilocócicas/transmisión , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/inmunología , Portador Sano/epidemiología , Prevalencia , Superantígenos/genética , Dedos/microbiología , Manipulación de Alimentos , Genes Bacterianos , Genotipo , Cavidad Nasal/microbiología , Antígenos Bacterianos/genética

RESUMEN

Staphylococcus aureus is among the microorganisms more frequently associated with subclinical bovine mastitis. S. aureus may produce several virulence factors. This study aimed at determining the frequency of virulence factors such as enterotoxins, toxic shock syndrome toxin 1, and ica adhesion genes. In addition, we assessed antimicrobial drug resistance in S. aureus isolated from clinical and subclinical cases of mastitis. A total of 88 cows with clinical or subclinical mastitis were sampled, resulting in 38 S. aureus isolates, from which 25 (65.78%) carried toxin genes, including seb, sec, sed, tst, and icaD adhesion gene. These S. aureus isolates belong to 21 ribotypes and three S. aureus strains belonged to the same ribotype producing ica adhesion gene. Approximately 90% of S. aureus strains obtained in our study demonstrated multiple resistance to different antimicrobial agents. The most efficacious antimicrobial agents against the isolates were gentamicin, amoxicillin, and norfloxacin. Gentamicin was the most efficacious agent inhibiting 78.95% of the S. aureus isolates. The least efficacious were penicillin, streptomycin, and ampicillin. Our results can help in understanding the relationship between virulence factors and subclinical mastitis caused by S. aureus. Further research about diversity of S. aureus isolates and genes responsible for the pathogenicity of subclinical mastitis is essential.

Asunto(s)

Toxinas Bacterianas/genética , Biopelículas , Enterotoxinas/genética , Mastitis Bovina/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus/genética , Superantígenos/genética , Amoxicilina/administración & dosificación , Animales , Brasil , Bovinos , Femenino , Gentamicinas/administración & dosificación , Norfloxacino/administración & dosificación , Staphylococcus aureus/aislamiento & purificación , Virulencia , Factores de Virulencia/genética

RESUMEN

A capacidade de produção de toxinas pelo Staphylococcus aureus no leite e produtos derivados está relacionado com surtos de intoxicação alimentar. Objetivou-se nesta pesquisa, estudar a ocorrência de genes que codificam para enterotoxinas estafilocócicas (sea, seb, sed, seg, seh e sei) e toxinas α e ß hemolítica (hla e hlb) em S. aureus isolados de 53 amostras de leite de tanques expansão comunitários no Estado de Alagoas, Brasil. Foram identificados 27 isolados (50,94%) como S. aureus pela amplificação do gene nuc. 13/27 isolados (48,1%) foram positivos para pelo menos um gene das enterotoxinas estudadas, sendo as frequências dos genes sea 33,3%, seh 18,5%, sei 11,1% e sed 7,4%; não entanto não foram identificados os genes seb e seg nestas bactérias. Para as toxinas hemolíticas, 51,9% dos isolados portavam ambos genes (hla e hlb), sendo a frequência para o gene hla de 81,5% e para o gene hlb de 51,9%. A frequência de genes das toxinas avaliadas é alta o que constitui um risco potencial para a saúde pública em especial, as enterotoxinas por serem termoestáveis e estarem asssociados com surtos de intoxicação alimentar.(AU)

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The capacity of toxin production by Staphylococcus aureus in milk and dairy products is associated with food poisoning outbreaks. The objective of this research was to study the frequency of genes encoding staphylococcal enterotoxin (sea, seb, sed, seg, seh and sei) and α and ß hemolytic toxins (hla and hlb) in S. aureus isolates from 53 milk samples from community tanks in the State of Alagoas, Brazil. Twenty-seven isolates (50.94%) were identified as S. aureus by nuc gene amplification; 13/27 isolates (48.1%) were positive for at least one gene of the studied enterotoxins and the frequency of genes sea was 33.3%, seh 18.5%, sei 11.1% and sed 7.4%; the seb and sec genes have not been identified in the bacteria. For the hemolytic toxins, 51.9% of isolates harbored both genes (hla and hlb), the frequency of hla gene was 81.5% and 51.9% for the hlb gene. The evaluated toxin-encoding gene frequency is high and constitutes a potential risk for public health, especially staphylococcal enterotoxin genes; because they are heat-stable enterotoxins and have been associated with food poisoning.(AU)

Asunto(s)

Staphylococcus aureus/genética , Superantígenos/genética , Leche/microbiología , Enterotoxinas , Reacción en Cadena de la Polimerasa/veterinaria

RESUMEN

A capacidade de produção de toxinas pelo Staphylococcus aureus no leite e produtos derivados está relacionado com surtos de intoxicação alimentar. Objetivou-se nesta pesquisa, estudar a ocorrência de genes que codificam para enterotoxinas estafilocócicas (sea, seb, sed, seg, seh e sei) e toxinas α e ß hemolítica (hla e hlb) em S. aureus isolados de 53 amostras de leite de tanques expansão comunitários no Estado de Alagoas, Brasil. Foram identificados 27 isolados (50,94%) como S. aureus pela amplificação do gene nuc. 13/27 isolados (48,1%) foram positivos para pelo menos um gene das enterotoxinas estudadas, sendo as frequências dos genes sea 33,3%, seh 18,5%, sei 11,1% e sed 7,4%; não entanto não foram identificados os genes seb e seg nestas bactérias. Para as toxinas hemolíticas, 51,9% dos isolados portavam ambos genes (hla e hlb), sendo a frequência para o gene hla de 81,5% e para o gene hlb de 51,9%. A frequência de genes das toxinas avaliadas é alta o que constitui um risco potencial para a saúde pública em especial, as enterotoxinas por serem termoestáveis e estarem asssociados com surtos de intoxicação alimentar.(AU)

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The capacity of toxin production by Staphylococcus aureus in milk and dairy products is associated with food poisoning outbreaks. The objective of this research was to study the frequency of genes encoding staphylococcal enterotoxin (sea, seb, sed, seg, seh and sei) and α and ß hemolytic toxins (hla and hlb) in S. aureus isolates from 53 milk samples from community tanks in the State of Alagoas, Brazil. Twenty-seven isolates (50.94%) were identified as S. aureus by nuc gene amplification; 13/27 isolates (48.1%) were positive for at least one gene of the studied enterotoxins and the frequency of genes sea was 33.3%, seh 18.5%, sei 11.1% and sed 7.4%; the seb and sec genes have not been identified in the bacteria. For the hemolytic toxins, 51.9% of isolates harbored both genes (hla and hlb), the frequency of hla gene was 81.5% and 51.9% for the hlb gene. The evaluated toxin-encoding gene frequency is high and constitutes a potential risk for public health, especially staphylococcal enterotoxin genes; because they are heat-stable enterotoxins and have been associated with food poisoning.(AU)

Asunto(s)

Staphylococcus aureus/genética , Superantígenos/genética , Leche/microbiología , Enterotoxinas , Reacción en Cadena de la Polimerasa/veterinaria

Asunto(s)

Humanos , Animales , Proteínas Bacterianas/inmunología , Superantígenos/inmunología , Toxinas Bacterianas/inmunología , Superantígenos/genética , Antígenos Bacterianos/inmunología

Asunto(s)

Proteínas Bacterianas/inmunología , Superantígenos/inmunología , Animales , Antígenos Bacterianos/inmunología , Toxinas Bacterianas/inmunología , Humanos , Superantígenos/genética

RESUMEN

INTRODUCTION: Staphylococcus aureus is a pathogen that causes food poisoning as well as hospital and community acquired infections. OBJECTIVE: Establish the profile of superantigen genes among hospital isolates in relation to clinical specimen type, susceptibility to antibiotics and hospital or community acquisition. METHODS: Eighty one isolates obtained from patients at Colombian hospital, were classified by antimicrobial susceptibility, specimen type and hospital or community acquired . The PCR uniplex and multiplex was used for detection of 22 superantigen genes (18 enterotoxins, tsst-1 and three exfoliative toxins). RESULTS: Ninety five point one percent of isolates harbored one or more of the genes with an average of 5.6 genes. Prevalence of individual genes was variable and the most prevalent was seg (51.9%). Thirty nine genotypes were obtained, and the genotype gimnou (complete egc cluster) was the most prevalent alone (16.0%) and in association with other genes (13.6%). The correlation between presence of superantigens and clinical specimen or antimicrobial susceptibility showed no significant difference. But there was significant difference between presence of superantigens and the origin of the isolates, hospital or community acquired (p= 0.049). CONCLUSIONS: The results show the variability of the superantigen genes profile in hospital isolates and shows no conclusive relationship with the clinical sample type and antimicrobial susceptibility, but there was correlation with community and hospital isolates. The analysis of the interplay between virulence, epidemic and antibiotic resistance of bacterial populations is needed to predict the future of infectious diseases.

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INTRODUCCIÓN: Staphylococcus aureus, es un patógeno que causa intoxicación alimentaria e infecciones hospitalarias y comunitarias. OBJETIVO: Establecer el perfil de genes de superantígenos en aislamientos hospitalarios correlacionándolos con el tipo de muestra clínica, susceptibilidad antimicrobiana y origen hospitalario o comunitario. MÉTODOS: Se analizaron 81 aislamientos de S. aureus de pacientes de un hospital colombiano. Fueron clasificadas por susceptibilidad antimicrobiana, tipo de muestra clínica y origen hospitalario o comunitario. Se detectó por PCR individual y múltiple 22 genes de superantígenos (18 enterotoxinas, una toxina del choque tóxico-1 y tres toxinas exfoliativas). RESULTADOS: El 95.1% albergaban uno o más genes de superantígenos con un promedio de 5.6 genes. La prevalencia individual fue variable y el gen con mayor prevalencia fue seg (51.9%). Se obtuvieron 39 genotipos, y el genotipo gimnou (cluster egc completo) fue el de mayor frecuencia (16.0%) y asociado con otros genes (13.6%). La correlación de superantígenos frente a tipo de muestra clínica y susceptibilidad antimicrobiana no mostró diferencia estadística significativa, pero hubo diferencia significativa con el tipo de aislamiento hospitalario o comunitario (p= 0.049). CONCLUSIONES: Los resultados muestran la diversidad genética en los aislados hospitalarios respecto a la presencia de superantígenos y no muestra una relación concluyente con el tipo de muestra clínica y susceptibilidad antimicrobiana pero sí con origen de los aislamientos comunitarios y hospitalarios. Un análisis de la interrelación entre la virulencia, epidemicidad y resistencia antimicrobiana de las poblaciones bacterianas es necesario para predecir el futuro de las enfermedades infecciosas.

Asunto(s)

Farmacorresistencia Bacteriana/genética , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/inmunología , Superantígenos/genética , Adulto , Secuencia de Bases , Infecciones Comunitarias Adquiridas/microbiología , Infección Hospitalaria/microbiología , Cartilla de ADN , Femenino , Humanos , Masculino , Técnicas de Amplificación de Ácido Nucleico , Estudios Prospectivos , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidad , Virulencia

RESUMEN

Introduction: Staphylococcus aureus is a pathogen that causes food poisoning as well as hospital and community acquired infections. Objective: Establish the profile of superantigen genes among hospital isolates in relation to clinical specimen type, susceptibility to antibiotics and hospital or community acquisition. Methods: Eighty one isolates obtained from patients at Colombian hospital, were classified by antimicrobial susceptibility, specimen type and hospital or community acquired. The PCR uniplex and multiplex was used for detection of 22 superantigen genes (18 enterotoxins, tsst-1 and three exfoliative toxins). Results: Ninety five point one percent of isolates harbored one or more of the genes with an average of 5.6 genes. Prevalence of individual genes was variable and the most prevalent was seg (51.9%). Thirty nine genotypes were obtained, and the genotype gimnou (complete egc cluster) was the most prevalent alone (16.0%) and in association with other genes (13.6%). The correlation between presence of superantigens and clinical specimen or antimicrobial susceptibility showed no significant difference. But there was significant difference between presence of superantigens and the origin of the isolates, hospital or community acquired (p= 0.049). Conclusions: The results show the variability of the superantigen genes profile in hospital isolates and shows no conclusive relationship with the clinical sample type and antimicrobial susceptibility, but there was correlation with community and hospital isolates. The analysis of the interplay between virulence, epidemic and antibiotic resistance of bacterial populations is needed to predict the future of infectious diseases.

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Introducción: Staphylococcus aureus, es un patógeno que causa intoxicación alimentaria e infecciones hospitalarias y comunitarias. Objetivo: Establecer el perfil de genes de superantígenos en aislamientos hospitalarios correlacionándolos con el tipo de muestra clínica, susceptibilidad antimicrobiana y origen hospitalario o comunitario. Métodos: Se analizaron 81 aislamientos de S. aureus de pacientes de un hospital colombiano. Fueron clasificadas por susceptibilidad antimicrobiana, tipo de muestra clínica y origen hospitalario o comunitario. Se detectó por PCR individual y múltiple 22 genes de superantígenos (18 enterotoxinas, una toxina del choque tóxico-1 y tres toxinas exfoliativas). Resultados: El 95.1% albergaban uno o más genes de superantígenos con un promedio de 5.6 genes. La prevalencia individual fue variable y el gen con mayor prevalencia fue seg (51.9%). Se obtuvieron 39 genotipos, y el genotipo gimnou (cluster egc completo) fue el de mayor frecuencia (16.0%) y asociado con otros genes (13.6%). La correlación de superantígenos frente a tipo de muestra clínica y susceptibilidad antimicrobiana no mostró diferencia estadística significativa, pero hubo diferencia significativa con el tipo de aislamiento hospitalario o comunitario (p= 0.049). Conclusiones: Los resultados muestran la diversidad genética en los aislados hospitalarios respecto a la presencia de superantígenos y no muestra una relación concluyente con el tipo de muestra clínica y susceptibilidad antimicrobiana pero sí con origen de los aislamientos comunitarios y hospitalarios. Un análisis de la interrelación entre la virulencia, epidemicidad y resistencia antimicrobiana de las poblaciones bacterianas es necesario para predecir el futuro de las enfermedades infecciosas.

Asunto(s)

Adulto , Femenino , Humanos , Masculino , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/inmunología , Superantígenos/genética , Farmacorresistencia Bacteriana/genética , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidad , Virulencia , Secuencia de Bases , Infección Hospitalaria/microbiología , Estudios Prospectivos , Cartilla de ADN , Infecciones Comunitarias Adquiridas/microbiología , Técnicas de Amplificación de Ácido Nucleico

RESUMEN

Horizontal gene transfer from retroviruses to mammals is well documented and extensive, but is rare between unrelated viruses with distinct genome types. Three herpesviruses encode a gene with similarity to a retroviral superantigen gene (sag) of the unrelated mouse mammary tumour virus (MMTV). We uncover ancient retroviral sags in over 20 mammals to reconstruct their shared history with herpesviral sags, revealing that the acquisition is a convergent evolutionary event. A retrovirus circulating in South American primates over 10 million years ago was the source of sag in two monkey herpesviruses, and a different retrovirus was the source of sag in a Peruvian rodent herpesvirus. We further show through a timescaled phylogenetic analysis that a cross-species transmission of monkey herpesviruses occurred after the acquisition of sag. These results reveal that a diverse range of ancient sag-containing retroviruses independently donated sag twice from two separate lineages that are distinct from MMTV.

Asunto(s)

Antígenos Virales/genética , Genes Virales/genética , Herpesviridae/genética , Retroviridae/genética , Superantígenos/genética , Animales , Aotidae , Quirópteros , Evolución Molecular , Transferencia de Gen Horizontal/genética , Herpesvirus Saimiriino 2 , Hylobates , Virus del Tumor Mamario del Ratón/genética , Ratones , Filogenia , Ratas , Rhadinovirus/genética , Ovinos , América del Sur

RESUMEN

BACKGROUND: Several human diseases are caused by Streptococcus pyogenes, ranging from common infections to autoimmunity. Characterization of the most prevalent strains worldwide is a useful tool for evaluating the coverage capacity of vaccines under development. In this study, a collection of S. pyogenes strains from Sao Paulo, Brazil, was analyzed to describe the diversity of strains and assess the vaccine coverage capacity of StreptInCor. METHODS: Molecular epidemiology of S. pyogenes strains was performed by emm-genotyping the 229 isolates from different clinical sites, and PCR was used for superantigen profile analysis. The emm-pattern and tissue tropism for these M types were also predicted and compared based on the emm-cluster classification. RESULTS: The strains were fit into 12 different emm-clusters, revealing a diverse phylogenetic origin and, consequently, different mechanisms of infection and escape of the host immune system. Forty-eight emm-types were distinguished in 229 samples, and the 10 most frequently observed types accounted for 69 % of all isolates, indicating a diverse profile of circulating strains comparable to other countries under development. A similar proportion of E and A-C emm-patterns were observed, whereas pattern D was less frequent, indicating that the strains of this collection primarily had a tissue tropism for the throat. In silico analysis of the coverage capacity of StreptInCor, an M protein-conserved regionally based vaccine candidate developed by our group, had a range of 94.5 % to 59.7 %, with a mean of 71.0 % identity between the vaccine antigen and the predicted amino acid sequence of the emm-types included here. CONCLUSIONS: This is the first report of S. pyogenes strain characterization in Sao Paulo, one of the largest cities in the world; thus, the strain panel described here is a representative sample for vaccine coverage capacity analysis. Our results enabled evaluation of StreptInCor candidate vaccine coverage capacity against diverse M-types, indicating that the vaccine candidate likely would induce protection against the diverse strains worldwide.

Asunto(s)

Vacunas Bacterianas/inmunología , Infecciones Estreptocócicas/prevención & control , Streptococcus pyogenes/inmunología , Secuencia de Aminoácidos , Antígenos Bacterianos/análisis , Antígenos Bacterianos/genética , Brasil/epidemiología , Análisis por Conglomerados , ADN Bacteriano/análisis , ADN Bacteriano/aislamiento & purificación , ADN Bacteriano/metabolismo , Genotipo , Humanos , Datos de Secuencia Molecular , Fenotipo , Filogenia , Reacción en Cadena de la Polimerasa , Alineación de Secuencia , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/patología , Streptococcus pyogenes/clasificación , Streptococcus pyogenes/genética , Superantígenos/análisis , Superantígenos/genética

RESUMEN

INTRODUCTION: Staphylococcus aureus produces a range of virulence factors such as toxic shock syndrome toxin-1. METHODS: In this cross-sectional study of 345 clinical S. aureus isolates, the presence of the tst gene was assessed by polymerase chain reaction (PCR). RESULTS: The study revealed 53/345 (15.4%) isolates were positive for the tst gene. The tst gene was present in 18.1% of methicillin-susceptible S. aureus (MSSA) isolates and 11.6% of methicillin-resistant S. aureus (MRSA) isolates (p = 0.136). CONCLUSIONS: These results reveal the remarkable risk of S. aureus infections in hospitals, regardless of methicillin-resistance status.

Asunto(s)

Toxinas Bacterianas/genética , Enterotoxinas/genética , Staphylococcus aureus/genética , Superantígenos/genética , Factores de Virulencia/genética , ADN Bacteriano/genética , Genes Bacterianos/genética , Genotipo , Hospitales de Enseñanza , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Staphylococcus aureus/enzimología , Staphylococcus aureus/aislamiento & purificación

RESUMEN

Lichen planus (LP) is a common inflammatory skin disease of unknown etiology. Reports of a common transactivation of quiescent human endogenous retroviruses (HERVs) support the connection of viruses to the disease. HERVs are ancient retroviral sequences in the human genome and their transcription is often deregulated in cancer and autoimmune diseases. We explored the transcriptional activity of HERV sequences as well as the antiviral restriction factor and interferon-inducible genes in the skin from LP patients and healthy control (HC) donors. The study included 13 skin biopsies from patients with LP and 12 controls. Real-time PCR assay identified significant decrease in the HERV-K gag and env mRNA expression levels in LP subjects, when compared to control group. The expressions of HERV-K18 and HERV-W env were also inhibited in the skin of LP patients. We observed a strong correlation between HERV-K gag with other HERV sequences, regardless the down-modulation of transcripts levels in LP group. In contrast, a significant up-regulation of the cytidine deaminase APOBEC 3G (apolipoprotein B mRNA-editing), and the GTPase MxA (Myxovirus resistance A) mRNA expression level was identified in the LP skin specimens. Other transcript expressions, such as the master regulator of type I interferon-dependent immune responses, STING (stimulator of interferon genes) and IRF-7 (interferon regulatory factor 7), IFN-ß and the inflammassome NALP3, had increased levels in LP, when compared to HC group. Our study suggests that interferon-inducible factors, in addition to their role in innate immunity against exogenous pathogens, contribute to the immune control of HERVs. Evaluation of the balance between HERV and interferon-inducible factor expression could possibly contribute to surveillance of inflammatory/malignant status of skin diseases.

Asunto(s)

Retrovirus Endógenos/metabolismo , Productos del Gen env/metabolismo , Productos del Gen gag/metabolismo , Interferón beta/metabolismo , Liquen Plano/inmunología , Proteínas de la Membrana/metabolismo , Proteínas Gestacionales/metabolismo , Piel/metabolismo , Superantígenos/metabolismo , Desaminasa APOBEC-3G , Adulto , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Citidina Desaminasa/genética , Citidina Desaminasa/metabolismo , Retrovirus Endógenos/genética , Femenino , Regulación Viral de la Expresión Génica , Productos del Gen env/genética , Productos del Gen gag/genética , Humanos , Vigilancia Inmunológica , Factor 7 Regulador del Interferón/genética , Factor 7 Regulador del Interferón/metabolismo , Interferón beta/genética , Liquen Plano/genética , Liquen Plano/virología , Masculino , Proteínas de la Membrana/genética , Persona de Mediana Edad , Proteínas de Resistencia a Mixovirus/genética , Proteínas de Resistencia a Mixovirus/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR , Proteínas Gestacionales/genética , Piel/virología , Superantígenos/genética , Activación Transcripcional , Regulación hacia Arriba , Adulto Joven

RESUMEN

BACKGROUND: Knowledge of nasal carriage is important in predicting staphylococcal infection, and no information exists regarding the endemicity of Staphylococcus aureus in Haiti. METHODS: We performed a cross-sectional analysis of S. aureus nasal screening in an acute care, a subacute rehabilitation, and a community setting, with a brief medical and epidemiological history. PCR-positive S. aureus screening nasal cultures underwent molecular analysis for spa type, SCCmec type, and virulence genes (Panton-Valentine leukocidin (PVL), toxic shock syndrome toxin (TSST), and arginine catabolic mobile element (ACME)), and were evaluated for antibiotic susceptibility using commercial tests. RESULTS: Overall carriage rates of 8.4% methicillin-susceptible S. aureus (MSSA) and 2.8% methicillin-resistant S. aureus (MRSA) were identified, with a high rate of tetracycline resistance. TSST and PVL genes were identified in MSSA. MRSA isolates contained no virulence markers. Unique MSSA phenotypes (i.e., linezolid-resistant, vancomycin-sensitive/daptomycin non-susceptible) were identified, as were two PVL-positive ST152 MSSA colonization isolates, previously geographically limited to Africa. CONCLUSIONS: We found a low S. aureus carriage rate with complete vancomycin susceptibility and high tetracycline resistance, which has important public health implications with regard to treatment. Additionally, the finding of PVL-positive MSSA isolates, including the expansion of a previously described limited 'divergent' clone, ST152, warrants further evaluation.

Asunto(s)

Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Toxinas Bacterianas/genética , Estudios Transversales , Terremotos , Enterotoxinas/genética , Exotoxinas/genética , Femenino , Haití/epidemiología , Humanos , Leucocidinas/genética , Masculino , Resistencia a la Meticilina , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Persona de Mediana Edad , Infecciones Estafilocócicas/virología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Superantígenos/genética , Factores de Virulencia/genética , Adulto Joven