RESUMO
The present study aimed to assess the occurrence and counts of Staphylococcus aureus in Brazilian artisanal cheeses (BAC) produced in five regions of Brazil: Coalho and Manteiga (Northeast region); Colonial and Serrano (South); Caipira (Central-West); Marajó (North); and Minas Artisanal cheeses, from Araxá, Campos das Vertentes, Cerrado, Serro and Canastra microregions (Southeast). The resistance to chlorine-based sanitizers, ability to attach to stainless steel surfaces, and antibiogram profile of a large set of S. aureus strains (n = 585) were assessed. Further, a total of 42 isolates were evaluated for the presence of enterotoxigenic genes (sea, seb, sec, sed, see, seg, sei, sej, and ser) and submitted to typing using pulsed-field gel electrophoresis (PFGE). BAC presented high counts of S. aureus (3.4-6.4 log CFU/g), varying from 25 to 62.5%. From the S. aureus strains (n = 585) assessed, 16% could resist 200 ppm of sodium hypochlorite, whereas 87.6% produced strong ability to attach to stainless steel surfaces, corroborating with S. aureus ability to persist and spread in the environment. Furthermore, the relatively high frequency (80.5%) of multidrug-resistant S. aureus and the presence of enterotoxin genes in 92.6% of the strains is of utmost attention. It reveals the lurking threat of SFP that can survive when conditions are favorable. The presence of enterotoxigenic and antimicrobial-resistant strains of S. aureus in cheese constitutes a potential risk to public health. This result calls for better control of cheese contamination sources, and taking hygienic measures is necessary for food safety. More attention should be paid to animal welfare and hygiene practices in some dairy farms during manufacturing to enhance the microbiological quality of traditional cheese products.
Assuntos
Queijo , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Animais , Staphylococcus aureus/genética , Queijo/microbiologia , Brasil , Microbiologia de Alimentos , Aço Inoxidável/análise , Enterotoxinas/genética , Leite/microbiologiaRESUMO
Microbial pigments are considered as one of the main sources of natural types, and the attention to them is increasing in the food and pharmaceutical industries. This study aimed to investigate the effects of pigments extracted from Micrococcus roseus (PEM) on the gene expression of a and b staphylococcal enterotoxins (sea and seb) and their acute toxicity. Real-time PCR was used to study the anti-enterotoxigenic activity of PEM against Staphylococcus aureus at sub-inhibitory concentrations. In addition, the acute toxicity of PEM was evaluated on albino mice through alkaline phosphatase (ALP), aspartate aminotransferas (AST), and alanine aminotransferase (ALT) of liver and its histopathological changes. Based on the results, the expression of sea and seb was decreased in the presence of PEM at sub-inhibitory concentrations. The 2-∆∆CT was measured 0.02 and 0.01 for the expression of sea and seb of S. aureus grown in the MHB containing 16 mg/ml PEM. The results showed that the expression of seb is more sensitive to PEM compared to the expression of sea. After treatment of mice with PEM for two weeks, the condition of mice was normal, and the results of liver enzymatic activities and histopathological changes showed insignificant difference compared to the control sample.
Assuntos
Enterotoxinas , Fígado , Pigmentos Biológicos , Staphylococcus aureus , Animais , Camundongos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Fígado/patologia , Fígado/efeitos dos fármacos , Enterotoxinas/genética , Enterotoxinas/toxicidade , Enterotoxinas/metabolismo , Micrococcus/efeitos dos fármacos , Micrococcus/genética , Antibacterianos/farmacologia , Antibacterianos/toxicidade , Infecções Estafilocócicas/microbiologia , Masculino , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Testes de Sensibilidade Microbiana , Alanina Transaminase/metabolismo , Alanina Transaminase/sangueRESUMO
This study emphasizes the importance of monitoring the microbiological quality of animal products, such as raw sheep's milk and cheese, to ensure food safety. In Brazil, there is currently no legislation governing the quality of sheep's milk and its derivatives. Therefore, this study aimed to evaluate: (i) the hygienic-sanitary quality of raw sheep's milk and cheese produced in southern Brazil; (ii) the presence of enterotoxins and Staphylococcus spp. in these products; and (iii) the susceptibility of the isolated Staphylococcus spp. to antimicrobial drugs and the presence of resistance genes. A total of 35 samples of sheep's milk and cheese were examined. The microbiological quality and presence of enterotoxins were accessed using Petrifilm and VIDAS SET2 methods, respectively. Antimicrobial susceptibility tests were conducted using VITEK 2 equipment and the disc diffusion method. The presence of resistance genes tet(L), sul1, sul2, ermB, tetM, AAC(6)', tetW, and strA were evaluated through PCR. In total, 39 Staphylococcus spp. were obtained. The resistance genes tetM, ermB, strA, tetL, sul1, AAC(6)', and sul2 were detected in 82%, 59%, 36%, 28%, 23%, 3%, and 3% of isolates, respectively. The findings revealed that both raw sheep's milk and cheese contained Staphylococcus spp. that exhibited resistance to antimicrobial drugs and harbored resistance genes. These results underscore the immediate need for specific legislation in Brazil to regulate the production and sale of these products.
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Patients with relapsed T cell acute lymphoblastic leukemia (T-ALL) have limited therapeutic options and poor prognosis. The finding of efficient strategies against this refractory neoplasm is a medical priority. Superantigens (SAgs) are viral and bacterial proteins that bind to major histocompatibility complex class II molecules as unprocessed proteins and subsequently interact with a high number of T cells expressing particular T cell receptor Vß chains. Although on mature T cells, SAgs usually trigger massive cell proliferation producing deleterious effects on the organism, in contrast, on immature T cells, they may trigger their death by apoptosis. On this basis, it was hypothesized that SAgs could also induce apoptosis in neoplastic T cells that are usually immature cells that probably conserve their particular Vß chains. In this work, we investigated the effect of the SAg Staphylococcus aureus enterotoxin E (SEE) (that specifically interacts with cells that express Vß8 chain), on human Jurkat T- leukemia line, that expresses Vß8 in its T receptor and it is a model of the highly aggressive recurrent T-ALL. Our results demonstrated that SEE could induce apoptosis in Jurkat cells in vitro. The induction of apoptosis was specific, correlated to the down regulation of surface Vß8 TCR expression and was triggered, at least in part, through the Fas/FasL extrinsic pathway. The apoptotic effect induced by SEE on Jurkat cells was therapeutically relevant. In effect, upon transplantation of Jurkat cells in the highly immunodeficient NSG mice, SEE treatment reduced dramatically tumor growth, decreased the infiltration of neoplastic cells in the bloodstream, spleen and lymph nodes and, most importantly, increased significantly the survival of mice. Taken together, these results raise the possibility that this strategy can be, in the future, a useful option for the treatment of recurrent T-ALL.
Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Superantígenos , Humanos , Camundongos , Animais , Enterotoxinas/farmacologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Apoptose , Receptores de Antígenos de Linfócitos TRESUMO
Staphylococcus aureus is a natural commensal microflora of humans which causes opportunistic infections due to its large arsenal of exotoxins, invasion, immune evasion, and antibiotic resistance mechanisms. The primary goal of this study is to develop a multiplex PCR (mPCR) assay for simultaneous detection of Staphylococcus aureus (nuc) and its virulence genes coding for prominent exotoxins namely alpha hemolysin (hla), enterotoxins A (sea), enterotoxin B (seb), toxic shock syndrome toxin (tsst-1), and the gene coding for methicillin resistance (mecA). A competitive internal amplification control (IAC) was included in the assay to exclude the false negative outcomes. Highly specific primer pairs were designed for the target genes using in silico resources. At the outset, monoplex PCRs were standardized using reference S. aureus strains. Primer specificity to the target genes was authenticated through restriction digestion analysis of amplified PCR products. Multiplex PCR was optimized in increments of one gene starting with nuc and IAC amplified simultaneously using one pair of primers (nuc) in a competitive manner. The mPCR assay was found to be highly sensitive with a detection limit of ~10 CFUs per reaction for pure cultures. Multiplex PCR assay was further evaluated on the retail and processed food samples to test the prevalence of S. aureus and study their exotoxin profiles. Of the 57 samples examined, 13 samples (22.80%) were found to be contaminated with S. aureus whose DNA was extracted after a 6-h enrichment period. Among these, a high percentage of hemolytic and enterotoxin A positive strains were encountered. The mPCR assay developed in this study would be a useful tool for rapid and reliable monitoring of S. aureus for food quality testing and from clinical infections.
Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Humanos , Staphylococcus aureus/genética , Reação em Cadeia da Polimerase Multiplex , Virulência , Enterotoxinas/genética , Exotoxinas , Inocuidade dos AlimentosRESUMO
Staphylococcal enterotoxins are a wide family of bacterial exotoxins with the capacity to activate as much as 20% of the host T cells, which is why they were called superantigens. Superantigens (SAgs) can cause multiple diseases in humans and cattle, ranging from mild to life-threatening infections. Almost all S. aureus isolates encode at least one of these toxins, though there is no complete knowledge about how their production is triggered. One of the main problems with the available evidence for these toxins is that most studies have been conducted with a few superantigens; however, the resulting characteristics are attributed to the whole group. Although these toxins share homology and a two-domain structure organization, the similarity ratio varies from 20 to 89% among different SAgs, implying wide heterogeneity. Furthermore, every attempt to structurally classify these proteins has failed to answer differential biological functionalities. Taking these concerns into account, it might not be appropriate to extrapolate all the information that is currently available to every staphylococcal SAg. Here, we aimed to gather the available information about all staphylococcal SAgs, considering their functions and pathogenicity, their ability to interact with the immune system as well as their capacity to be used as immunotherapeutic agents, resembling the two faces of Dr. Jekyll and Mr. Hyde.
Assuntos
Staphylococcus aureus , Superantígenos , Humanos , Animais , Bovinos , Enterotoxinas , Exotoxinas , Staphylococcus , ImunidadeRESUMO
Background: Coriander, like other leafy green vegetables, is available all year round and is commonly consumed raw in Mexico as in other countries in the preparation of street or homemade food. Bacillus cereus (B. cereus) is a microorganism that can reach coriander because it is usually found in the soil and in some regions the vegetables are irrigated with polluted water. Therefore, the aim of this study was to determinate the presence of B. cereus in coriander used for human consumption in southwestern Mexico and determine the toxigenic profile, biofilm production, genes associated with the production of biofilms, sporulation rates, enzymatic profile, psychotropic properties, and genetic diversity of B. cereus. Methods: Fresh coriander samples were collected from several vegetable retailers in different markets, microbiological analysis was performed. Molecular identification, genes related to the production of biofilm, and toxin gene profiling of B. cereus isolates were determined by PCR. The biofilm formation was measured by performing a crystal violet assay. The genetic diversity of B. cereus strains was determined by PCR of repetitive elements using oligonucleotide (GTG) 5. Results: We found a frequency of B. cereus in vegetables was 20% (13/65). In this study, no strains with genes for the HBL toxin were found. In the case of genes related to biofilms, the frequency was low for sipW [5.8%, (1/17)] and tasA [11.7%, (2/17)]. B. cereus strains produce a low amount of biofilm with sporulation rates around 80%. As for genetic diversity, we observed that strains isolated from the same market, but different vegetable retailers are grouped into clusters. In the coriander marketed in southwestern Mexico, were found B. cereus strains with genes associated with the production of diarrheal toxins. Together, these results show actual information about the state of art of B. cereus strains circulating in the southwestern of Mexico.
Assuntos
Coriandrum , Enterotoxinas , Humanos , Enterotoxinas/análise , Microbiologia de Alimentos , Bacillus cereus/genética , México , Verduras/microbiologia , Variação Genética/genéticaRESUMO
This study aimed to identify potentially pathogenic microorganisms (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus, and several virulence genes) in unpasteurized cheese production in the northeastern region of the state of São Paulo, Brazil. Listeria species were detected in 68 (64.14%) out of 106 samples of bovine feces, swabs from milkers' and cheese handlers' hands, milking buckets, raw milk, whey, water, cheese processing surface,s and utensils. All the samples collected at one farm were contaminated with Listeria spp. L. innocua, L. seeligeri, L. ivanovii, or L. monocytogenes were not detected in the samples collected in this study. A set of 391 Staphylococcus spp. isolates were obtained in these samples, from which 60 (15.31%) were identified as S. aureus using PCR (Polymerase Chain Reaction). S. aureus carrying virulence genes (eta, hlg, seg, seh, sei) were detected in milk, in swabs from cheese handler's hands, whey, milk, sieves, buckets, and cheese. The hlg gene (encodes gamma hemolysin) was detected in all the S. aureus isolates. These findings show that poor hygienic practice is associated with a higher risk of pathogenic bacteria in milk or cheese, providing useful information for public health authorities to increase food safety surveillance and prevent the dissemination of pathogens.
O objetivo desse estudo foi identificar microrganismos potencialmente patogênicos (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus e diversos genes de virulência) na produção de queijos de leite cru na região noroeste do Estado de São Paulo, Brasil. Listeria foram detectadas em 68 (64,14%) das 106 amostras obtidas de fezes bovinas, suabes das mãos de ordenhadores e queijeiros, baldes, leite cru, soro, água, superfícies e utensílios da produção de queijos. Todas as amostras coletadas em uma fazenda estavam contaminadas com Listeria spp. L. innocua, L. seeligeri, L. ivanovii, e L. monocytogenes não foram detectadas nas amostras coletadas nesse estudo. Um conjunto de 391 isolados de Staphylococcus spp. foram obtidos das amostras, e desses 60 (15,31%) foram identificados como S. aureus pela PCR (Polymerase Chain Reaction). S. aureus contendo genes de virulência (eta, hlg, seg, seh, sei) foram detectados em leite, mãos dos ordenhadores, soro, utensílios e queijos. O gene hlg (gama-hemolisina)foi detectado em todos os isolados de S. aureus.Esses resultados demonstram que práticas inadequadas de higiene estão associadas com um maior risco da presença de bactérias patogênicas no leite e queijos crus, fornecendo informações para as autoridades de saúde pública para incrementarem a vigilância e prevenirem a disseminação de patógenos.
Assuntos
Staphylococcus aureus , Contaminação de Alimentos/análise , Higiene dos Alimentos , Queijo/análise , Reação em Cadeia da Polimerase , Inocuidade dos Alimentos/métodos , Microbiologia de Alimentos , ListeriaRESUMO
More than 30 types of artisanal cheeses are known in Brazil; however, microorganisms, such as Staphylococcus spp., can contaminate raw milk cheeses through different sources, from milking to processing. Staphylococcal food poisoning results from the consumption of food in which coagulase-positive staphylococci, mostly Staphylococcus aureus, have developed and produced enterotoxins. In addition, an emerging public health concern is the increasing antimicrobial resistance of some Staphylococcus strains. Furthermore, the ability of Staphylococcus spp. in sharing antibiotic resistance-related genes with other bacteria increases this problem. In light of these observations, this review aims to discuss the presence of, enterotoxins of, and antibiotic-resistant of Staphylococcus spp. in Brazilian artisanal cheese produced with raw milk.
Assuntos
Queijo , Animais , Antibacterianos/farmacologia , Brasil , Queijo/microbiologia , Farmacorresistência Bacteriana , Enterotoxinas/genética , Microbiologia de Alimentos , Humanos , Leite/química , Staphylococcus , EstudantesRESUMO
Staphylococcus aureus is an opportunistic and ubiquitous pathogen found in the skin, nares, and mucosal membranes of mammals. Increasing resistance to antimicrobials including methicillin has become an important public concern. One hundred and eight (108) S. aureus strains isolated from a total of 572 clinical and animal products samples, were investigated for their biofilm capability, methicillin resistance, enterotoxin genes, and genetic diversity. Although only one strain isolated from raw retail was found as a strong biofilm producer, the percentage of antimicrobial resistance pattern was relatively higher. 17.59% of S. aureus strains tested in this study were resistant to cefoxitin and identified as methicillin-resistant S. aureus (MRSA) isolates. mecA and mecC harboring S. aureus strains were detected at a rate of 2.79% and 0.93%, respectively. In addition, staphylococcal enterotoxin genes including Sea, Seb, Sec, and Sed genes were found to be 18.5%, 32.4%, 6.5% and 3.7%, respectively. The phylogenetic relationship among the isolates showed relationship between joint calf and cow milk isolates. Multi locus sequence typing (MLST) revealed three different sequence types (STs) including ST84, ST829, and ST6238. These findings highlight the development and spread of MRSA strains with zoonotic potential in animals and the food chain throughout the world.
Staphylococcus aureus é um patógeno dúctil e ubíquo encontrado na pele, narinas e membranas mucosas de mamíferos. O aumento da resistência aos antimicrobianos, incluindo a meticilina, tornou-se uma importante preocupação pública. Cento e oito (108) cepas de S. aureus isoladas de um total de 572 amostras clínicas e de produtos animais foram investigadas por sua capacidade de biofilme, resistência à meticilina, genes de enterotoxinas e diversidade genética. Embora apenas uma cepa isolada do cru tenha sido encontrada como forte produtora de biofilme, a porcentagem do padrão de resistência antimicrobiana foi relativamente maior. Parte das cepas (17,59%) de S. aureus testadas neste estudo eram resistentes à cefoxitina e identificadas como isolados de MRSA. mecA e mecC abrigando cepas de S. aureus foram detectados a uma taxa de 2,79% e 0,93%, respectivamente. Além disso, verificou-se que os genes da enterotoxina estafilocócica, incluindo os genes Sea, Seb, Sec e Sed, eram 18,5%, 32,4%, 6,5% e 3,7%, respectivamente. A relação filogenética entre os isolados mostrou relação entre os isolados de bezerro e leite de vaca. A tipagem de sequência multiloco (MLST) revelou três tipos de sequência diferentes (STs), incluindo ST84, ST829 e ST6238. Essas descobertas destacam o desenvolvimento e a disseminação de cepas de MRSA com potencial zoonótico em animais e na cadeia alimentar em todo o mundo.
Assuntos
Animais , Intoxicação Alimentar Estafilocócica/epidemiologia , Turquia/epidemiologia , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/genética , Queijo/microbiologia , Leite/microbiologia , EnterotoxinasRESUMO
ABSTRACT: Staphylococcus aureus is an opportunistic and ubiquitous pathogen found in the skin, nares, and mucosal membranes of mammals. Increasing resistance to antimicrobials including methicillin has become an important public concern. One hundred and eight (108) S. aureus strains isolated from a total of 572 clinical and animal products samples, were investigated for their biofilm capability, methicillin resistance, enterotoxin genes, and genetic diversity. Although only one strain isolated from raw retail was found as a strong biofilm producer, the percentage of antimicrobial resistance pattern was relatively higher. 17.59% of S. aureus strains tested in this study were resistant to cefoxitin and identified as methicillin-resistant S. aureus (MRSA) isolates. mecA and mecC harboring S. aureus strains were detected at a rate of 2.79% and 0.93%, respectively. In addition, staphylococcal enterotoxin genes including Sea, Seb, Sec, and Sed genes were found to be 18.5%, 32.4%, 6.5% and 3.7%, respectively. The phylogenetic relationship among the isolates showed relationship between joint calf and cow milk isolates. Multi locus sequence typing (MLST) revealed three different sequence types (STs) including ST84, ST829, and ST6238. These findings highlight the development and spread of MRSA strains with zoonotic potential in animals and the food chain throughout the world.
RESUMO: Staphylococcus aureus é um patógeno dúctil e ubíquo encontrado na pele, narinas e membranas mucosas de mamíferos. O aumento da resistência aos antimicrobianos, incluindo a meticilina, tornou-se uma importante preocupação pública. Cento e oito (108) cepas de S. aureus isoladas de um total de 572 amostras clínicas e de produtos animais foram investigadas por sua capacidade de biofilme, resistência à meticilina, genes de enterotoxinas e diversidade genética. Embora apenas uma cepa isolada do cru tenha sido encontrada como forte produtora de biofilme, a porcentagem do padrão de resistência antimicrobiana foi relativamente maior. Parte das cepas (17,59%) de S. aureus testadas neste estudo eram resistentes à cefoxitina e identificadas como isolados de MRSA. mecA e mecC abrigando cepas de S. aureus foram detectados a uma taxa de 2,79% e 0,93%, respectivamente. Além disso, verificou-se que os genes da enterotoxina estafilocócica, incluindo os genes Sea, Seb, Sec e Sed, eram 18,5%, 32,4%, 6,5% e 3,7%, respectivamente. A relação filogenética entre os isolados mostrou relação entre os isolados de bezerro e leite de vaca. A tipagem de sequência multiloco (MLST) revelou três tipos de sequência diferentes (STs), incluindo ST84, ST829 e ST6238. Essas descobertas destacam o desenvolvimento e a disseminação de cepas de MRSA com potencial zoonótico em animais e na cadeia alimentar em todo o mundo.
RESUMO
Staphylococcus aureus is one of the most common pathogens associated with food poisoning, which is caused by the ingestion of food contaminated with staphylococcal enterotoxins (SE). Our study aims at evaluating the occurrence and expression of five SE genes (sea, seb, sec, sed, and see) in S. aureus previously isolated from broiler carcasses. Besides that, it also presents an in vitro analysis of the effects of sodium chloride and temperature on the levels of transcriptional expression. A total of 30 S. aureus isolates were investigated for the presence of SEs by PCR assay. The expression level and the effects of sodium chloride (2.5% NaCl), as well as temperature (8 ºC and 12 ºC), on the transcriptional expression, were evaluated by a quantitative reverse transcription PCR (RT-qPCR). Twelve isolates carried at least one of the SE genes. Among them, five representative isolates presented transcriptional expression for at least one gene. Both sodium chloride and low temperatures interfered with the expression of the SE genes, decreasing their values. However, one isolate displayed relative expression 2.25 times higher for sed gene than S. aureus FRI 361 in optimal conditions (p < 0.05), demonstrating their toxigenic potential even under salt stress. There was no evidence of enterotoxin gene expression at 8 ºC.
Assuntos
Microbiologia de Alimentos , Regulação Bacteriana da Expressão Gênica , Cloreto de Sódio , Infecções Estafilocócicas , Staphylococcus aureus , Temperatura , Animais , Galinhas , Enterotoxinas/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Doenças das Aves Domésticas/microbiologia , Cloreto de Sódio/farmacologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genéticaRESUMO
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.
Assuntos
Enterotoxinas/análise , Imunoensaio/métodos , Superantígenos/análise , Ressonância de Plasmônio de Superfície/métodos , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos , Técnicas Biossensoriais/métodos , Materiais Revestidos Biocompatíveis , Enterotoxinas/genética , Enterotoxinas/imunologia , Microbiologia de Alimentos , Humanos , Limite de Detecção , Nanopartículas , Coelhos , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Dióxido de Silício , Intoxicação Alimentar Estafilocócica/diagnóstico , Staphylococcus aureus/química , Staphylococcus aureus/genética , Staphylococcus aureus/imunologia , Superantígenos/genética , Superantígenos/imunologiaRESUMO
Introducción: Staphylococcus ocasiona con frecuencia intoxicaciones alimentarias; en Cuba es una de las principales causas de brotes. Objetivo: analizar el perfil del riesgo de brotes alimentarios por Staphylococcus en Cuba. Métodos: Se realizó un estudio observacional analítico sobre los factores higiénicos y epidemiológicos asociados al riesgo de la intoxicación alimentaria por Staphylococcus en Cuba, en el Instituto Nacional de Higiene Epidemiología y Microbiología, durante el periodo de enero a noviembre de 2018. La información se obtuvo mediante revisión bibliográfica sistémica, análisis de datos del Laboratorio de Referencia Nacional en Microbiología Sanitaria y informes de brotes de la Dirección Nacional de Salud Ambiental. Se estimó el riesgo microbiológico mediante el programa semicuantitativo Ross-Sumner. Resultados: Se identificó como principal peligro Stahylococcus aureus, productores de enterotoxina A y la determinación de aislamientos resistentes a los antimicrobianos, como Stahylococcus aureus meticilina resistentes. Los alimentos más implicados fueron los productos de repostería y la inocuidad se afectó en mayor frecuencia por la contaminación cruzada en el 31,4 por ciento brotes y la inadecuada conservación en 46,1 por ciento. La predicción de personas que enferman por año en la población de interés fue de 6 260. Conclusiones: El riesgo de la ocurrencia de brotes por Staphylococcus se estimó como alto; la vigilancia se recomienda en alimentos que requieren manipulación directa y no se aplica tratamiento térmico antes del consumo, con gestiones de riesgo dirigidas a productores y consumidores(AU)
Introduction: Staphylococcus is a frequent cause of food poisoning. In Cuba it is one of the main causes of outbreaks. Objective: Analyze the risk profile of staphylococcal food poisoning outbreaks in Cuba. Methods: An observational analytical study was conducted about hygienic and epidemiological factors associated to the risk for staphylococcal food poisoning in Cuba. The study was carried out at the National Institute of Hygiene, Epidemiology and Microbiology from January to November 2018. The information was obtained from a systematic bibliographic review, analysis of data from the Medical Microbiology National Reference Laboratory, and outbreak reports from the National Environmental Health Division. Microbiological risk was estimated with Ross-Sumner semi-quantitative software. Results: The main hazard identified was Staphylococcus aureus, enterotoxin A producers and determination of antimicrobial resistant isolates like methicillin-resistant Staphylococcus aureus. The food items most commonly involved were sweets, and safety was most frequently affected by cross-contamination in 31.4 percent of the outbreaks and inadequate preservation in 46.1 percent. Prediction of members of the population of interest becoming ill every year was 6 260. Conclusions: Risk for the occurrence of staphylococcal food poisoning outbreaks was considered to be high; surveillance is recommended of food items requiring direct manipulation and appropriate thermal treatment is not applied before consumption, with risk management actions aimed at manufacturers and consumers(AU)
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Humanos , Intoxicação Alimentar Estafilocócica/complicações , Intoxicação Alimentar Estafilocócica/prevenção & controle , Medição de RiscoRESUMO
Gastrointestinal infections caused by Clostridium difficile lead to significant impact in terms of morbidity and mortality, causing from mild symptoms, such as a low-grade fever, watery stools, and minor abdominal cramping as well as more severe symptoms such as bloody diarrhea, pseudomembrane colitis, and toxic megacolon. Vaccination is a viable approach to fight against C. difficile and several efforts in this direction are ongoing. Plants are promising vaccine biofactories offering low cost, enhanced safety, and allow for the formulation of oral vaccines. Herein, the CdeM protein, which is a spore antigen associated with immunoprotection against C. difficile, was selected to begin the development of plant-based vaccine candidates. The vaccine antigen is based in a fusion protein (LTB-CdeM), carrying the CdeM antigen, fused to the carboxi-terminus of the B subunit of the Escherichia coli heat-labile enterotoxin (LTB) as a mucosal immunogenic carrier. LTB-CdeM was produced in plants using a synthetic optimized gene according codon usage and mRNA stability criteria. The obtained transformed tobacco lines produced the LTB-CdeM antigen in the range of 52-90 µg/g dry weight leaf tissues. The antigenicity of the plant-made LTB-CdeM antigen was evidenced by GM1-ELISA and immunogenicity assessment performed in test mice revealed that the LTB-CdeM antigen is orally immunogenic inducing humoral responses against CdeM epitopes. This report constitutes the first step in the development of plant-based vaccines against C. difficile infection.
Assuntos
Antígenos de Bactérias , Clostridioides difficile/genética , Plantas Geneticamente Modificadas , Esporos Bacterianos/genética , Vacinas de Plantas Comestíveis , Administração Oral , Animais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/genética , Antígenos de Bactérias/metabolismo , Enterotoxinas/genética , Proteínas de Escherichia coli/genética , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos BALB C , Agricultura Molecular , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , Vacinas de Plantas Comestíveis/genética , Vacinas de Plantas Comestíveis/imunologia , Vacinas de Plantas Comestíveis/metabolismoRESUMO
Bacillus cereus is a human pathogenic bacterium found in foods with the potential to cause emesis and diarrhea. This study estimated the presence, toxigenic and genomic diversity of B. cereus s.l. obtained from cassava starch samples collected in bakeries and powdered food companies in Medellín (Colombia). Bacillus cereuss.l. was found in 43 of 75 (57%) cassava starch samples and 98 isolates were obtained. The nheABC, hblCDAB, cytK2, entFM and cesB toxin genes were detected by multiplex PCR and the most frequent operon was nheABC, whereas cesB gene was not found. Twelve toxigenic profiles were determined by the detection of toxin genes, and the most frequent profiles harbored all enterotoxin genes. A broad genomic diversity was detected according to GTG5-PCR fingerprinting results with 76 B. cereus s.l. grouped in sixteen clusters and the 22 isolates clustering separately. No relationship was observed between genomic background and toxigenic profiles. In general, the results showed a high genomic and enterotoxigenic diversity in B. cereus s.l. found in cassava starch. These results should incentive future studies to understand the distribution of B. cereus s.l. isolated on raw materials in comparison with finished products.
Assuntos
Bacillus cereus/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Enterotoxinas/genética , Microbiologia de Alimentos , Proteínas Hemolisinas/genética , Manihot/microbiologia , Amido/análise , Bacillus cereus/isolamento & purificação , Bacillus cereus/metabolismo , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Enterotoxinas/metabolismo , Manipulação de Alimentos , Regulação Bacteriana da Expressão Gênica , Genótipo , Proteínas Hemolisinas/metabolismoRESUMO
Verificamos a qualidade microbiológica de alimentos da culinária japonesa comercializados em restaurantes de Botucatu/SP. Foram analisadas 70 amostras coletadas em 14 restaurantes, em busca de Bacillus cereus, Staphylococcus aureus, Vibrio parahaemolyticus, Salmonella e coliformes termotolerantes (CT). Isolados de S. aureus foram investigados quanto à presença de genes que codificam a produção de biofilme (bap, icaA e icaD) e algumas enterotoxinas (sea-sei). A formação de biofilme in vitro foi testada. Das 70 amostras, 50 (71,4%) apresentaram CT e 27 (38,6%) eram impróprias para consumo. Salmonella, V. parahaemolyticus e B. cereus não foram detectados. S. aureus foi observado em 5 (7,1%) amostras. Os genes clássicos de enterotoxinas não foram detectados. O gene seh foi observado em 2 isolados, enquanto seg e sei estiveram presentes outros 2 isolados. Todas as cepas de S. aureus foram produtoras moderadas de biofilme. O gene icaD estava presente em todos os isolados e o icaA em 40%. Devido à presença de CT, indicador de contaminação fecal, e S. aureus, indicador de falta de higiene durante o manuseio, a comida japonesa comercializada em Botucatu-SP não pode ser considerada segura para consumo.(AU)
We verified the microbiological quality of Japanese cuisine foods sold in restaurants in Botucatu/SP. Seventy samples collected from 14 restaurants were analyzed, searching for Bacillus cereus Staphylococcus aureus, Vibrio parahaemolyticus, Salmonella and thermotolerant coliforms (TC). S. aureus isolates were investigated for the presence of genes encoding the biofilm production (bap, icaA and icaD) and some enterotoxins (sea-sei). The biofilm formation in vitro was tested. Considering the 70 samples, 50 (71.4%) had TC, and 27 (38.6%) were unfit for consumption. Salmonella, V. parahaemolyticus and B. cereus were not detected. S. aureus was observed in 5 (7.1%) samples. The classical enterotoxin genes were not detected. The seh gene was observed in 2 isolates, while both seg and sei were present in more 2 isolates. All strains of S. aureus were moderate producers of biofilm. The icaD gene was present in all isolates and icaA in 40%. Due to the presence of TC, an indicator of fecal contamination and S. aureus, also an indicator of poor hygiene during handling, Japanese food sold in Botucatu-SP cannot be considered safe for consumption.(AU)
Assuntos
Restaurantes , Enterotoxinas , Microbiologia de Alimentos/métodos , Brasil , Técnicas Microbiológicas/métodosRESUMO
Foodborne illnesses, such as infections or food poisoning, can be caused by bacterial biofilms present in food matrices or machinery. The production of biofilms by several strains of Bacillus cereus on different materials under different culture conditions was determined, as well as the relationship of biofilms with motility, in addition to the enterotoxigenic profile and candidate genes that participate in the production of biofilms. Biofilm production of B. cereus strains was determined on five materials: glass, polystyrene, polyethylene, polyvinylchloride (PVC), PVC/glass; in three culture media: Phenol red broth, tryptic soy broth, and brain heart infusion broth; in two different temperatures (37 °C and 25 °C), and in two different oxygen conditions (oxygen and CO2 tension). Furthermore, the strains were molecularly characterized by end-point polymerase chain reaction. Motility was determined on semi-solid agar. The B. cereus strains in this study were mainly characterized as enterotoxigenic strains; statistically significant differences were found in the PVC material and biofilm production. Motility was positively associated with the production of biofilm in glass/PVC. The sipW and tasA genes were found in two strains. The results of this study are important in the food industry because the strains carry at least one enterotoxin gene and produce biofilms on different materials.
RESUMO
A simple, cheap, and less aggressive immobilization procedure for biomolecules using reduced graphene oxide (rGO) was employed to prepare an impedimetric immunosensor for detection of staphylococcal enterotoxin A (SEA) from Staphylococcus aureus in milk samples. The scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) were used to monitor the single steps of the electrode assembly process. The glassy carbon (GC)/rGO platform detected the antigen-antibody binding procedures of SEA with concentrations of 0.5 to 3.5 mg L-1 via impedance changes in a low frequency range. The impedimetric immunosensor was successfully applied for the determination of SEA in milk samples.
RESUMO
Staphylococcus aureus is an important intramammary pathogen for dairy cows that also is remarkably important for public health. Multiple virulence factors can be involved simultaneously during the pathogenesis of a staphylococcal disease, including adhesion proteins, extracellular enzymes, and toxins. The main objective of this study was to assess virulence factors that are associated with cow intramammary infection (IMI) and of human health concern among Staph. aureus isolates obtained from bulk tank milk (BTM) and adherences on milking equipment surfaces. A total of 166 Staph. aureus isolates from 23 dairy farms were characterized according to their virulence profiles. For virulence factors of importance in IMI, the presence of the virulence markers thermonuclease (nuc) and coagulase (coa) and virulence genes such as fibronectin (fnbA) and intercellular adhesion (icaA, icaD) were assessed. For virulence factors of public health concern, presence of antimicrobial resistance (mecA and mecC) and enterotoxin (sea and seb) genes were analyzed. Among all Staph. aureus isolates, 5 virulence profiles were found; the profile nuc(+)coa(+)fnbA(+)icaA(+)icaD(+)mecA(-)mecC(-)sea(-)seb(-) was the most frequently observed (21 out of 23 dairy farms). No differences were found between the virulence profile frequencies of Staph. aureus from BTM and adherences on milking equipment surfaces. The virulence profiles most frequently observed included genes involved in the adherence and biofilm-forming ability of Staph. aureus, which could represent a potential advantage for the bacterium during the early stages of IMI colonization and for persistence on surfaces. Our results indicate a greater frequency of virulence factors of importance for IMI pathogenesis than virulence factors of public health concern, consistent with the dairy origin of isolates. The mecA, mecC, and seb genes were not observed among Staph. aureus isolates analyzed in this study. However, the sea gene was detected in 3 Staph. aureus isolated from BTM, thus posing a potential public health threat. Our results emphasize the importance of understanding the epidemiology and dynamics of Staph. aureus on dairy farms as a tool for the improvement of udder health and milk safety.