Bacillus cereus is traditionally thought to be the only member of its genus accepted as a pathogen in foods like grains, fruits, vegetables and milk due to the presence of the nonhemolytic (Nhe) operon. However, many other Bacillus spp. may also harbor the Nhe operon and be pathogenic. Real-time PCR targeted the nheA gene in 37 samples obtained from food, soil, and reference cultures by analyzing the standard deviations of melt peaks. Rep-PCR was used to compare the banding patterns of each sample against B. cereus ATCC14579 and three B. thuringiensis strains to “fingerprint” each isolate. Of the original 43 isolated tested, 37 were Gram-positive rods. The remaining six samples were Gram-positive cocci. Twenty-five of the 37 Gram-positive Bacillus spp. were nheA positive, while twelve were negative. Many of the nheA positive strains were species not previously known to contain Nhe, and were capable of causing gastroenteritis in consumers. / Department of Biology

Introdução: Staphylococcus aureus são microrganismos causadores de diversos tipos de doenças. Existem dois grandes agravantes a sua presença: a produção de toxinas e a resistência a antimicrobianos. S. aureus produzem enterotoxinas termolábeis que, quando presentes nos alimentos, podem levar a uma toxinfecção a quem o consumir. Esta espécie também é conhecida por facilmente responder adaptativamente ao uso de drogas tornandose cada vez mais difícil controlá-la. Um dos maiores responsáveis por esta preocupação são os MRSA (methicillin-resistant Staphylococcus aureus), resistentes a beta-lactâmicos através da produção de uma proteína diferenciada de parede codificada pelo gene mecA. A presença deste patógeno resistente fora do ambiente hospitalar é registrada há alguns anos e pouco a pouco vem se descobrindo que a via alimentar pode ser um meio deste gene se disseminar. Objetivos: procurar pelo gene mecA e o codificador da enterotoxina em Staphylococcus aureus de amostras alimentares para discutir a presença do gene de resistência em uma nova via de transmissão e a validade de apenas se fiscalizar a presença apenas de Staphylococcus coagulase positivo em produtos alimentares como forma de manter o alimento seguro contra toxinfecções. Métodos: Cinquenta e sete amostras de S. aureus provenientes de amostras de quatro tipos de fontes alimentares foram testadas por PCR com primer específico para o gene mecA e para o gene codificador da enterotoxina. Resultados: Destas, cinco (8,8 por cento do total) amostras apresentaram o gene de resistência e onze (19,2 por cento do total) continham o gene codificador da enterotoxina termolábil. Conclusão: A presença do gene de enterotoxina em produtos prontos para consumo e peixe cru de feira é uma realidade, assim como o debate sobre qual a melhor forma de se legislar sobre o assunto que deve ser mantido e melhor avaliado. Já no caso do gene de resistência, evidenciou-se que a via alimentar é sim local de circulação do gene de resistência. Também é a primeira vez que se notifica o gene mecA em alimentos prontos para consumo no Brasil e América Latina / Introduction: Staphylococcus aureus are a bacterium that causes various types of diseases. There are two major aggravating to its presence: the toxins production and antimicrobial resistance. S. aureus produce heat-labile enterotoxina that, when present in food, can lead to poisoning of those who consume. This specie is also known to easily respond adaptively to drug use becoming increasingly difficult to control it. One of the main reasons for this concern are MRSA (methicillin-resistant Staphylococcus aureus) which are resistant to betalactams drugs through a differentiated wall protein production encoded by the mecA gene. The presence of this resistant pathogen outside hospitals has been recorded a few years ago and gradually comes to discover that the food chain can be a way for the gene spread. Objectives: Search for the mecA gene and the enterotoxins encoded gene in Staphylococcus aureus from food samples to discuss the presence of the resistance gene in a new transmission route and the validity of only review the presence of Staphylococcus coagulase positive in food product as a way to keep insurance against food poisoning. Methods: Fifty-seven samples of S. aureus from five different sources of food samples were tested by PCR with specific primer for the mecA gene and the enterotoxins gene. Results: Of these, five (8,8 per cent of total) samples showed the resistance gene and eleven (19,2 per cent of total) contained the gene encoding the heat-labile enterotoxin. Conclusion: The presence of enterotoxin encoded gene in food products ready for consumption and raw fish is a fact and a debate about how best to legislate should be maintained and better evaluated. In the case of the resistance gene, the food chain is really a way where this gene can spread. It is also the first time the mecA gene from food ready for consumption is reported in Brazil and Latin America

Introdução: Staphylococcus aureus são microrganismos causadores de diversos tipos de doenças. Existem dois grandes agravantes a sua presença: a produção de toxinas e a resistência a antimicrobianos. S. aureus produzem enterotoxinas termolábeis que, quando presentes nos alimentos, podem levar a uma toxinfecção a quem o consumir. Esta espécie também é conhecida por facilmente responder adaptativamente ao uso de drogas tornandose cada vez mais difícil controlá-la. Um dos maiores responsáveis por esta preocupação são os MRSA (methicillin-resistant Staphylococcus aureus), resistentes a beta-lactâmicos através da produção de uma proteína diferenciada de parede codificada pelo gene mecA. A presença deste patógeno resistente fora do ambiente hospitalar é registrada há alguns anos e pouco a pouco vem se descobrindo que a via alimentar pode ser um meio deste gene se disseminar. Objetivos: procurar pelo gene mecA e o codificador da enterotoxina em Staphylococcus aureus de amostras alimentares para discutir a presença do gene de resistência em uma nova via de transmissão e a validade de apenas se fiscalizar a presença apenas de Staphylococcus coagulase positivo em produtos alimentares como forma de manter o alimento seguro contra toxinfecções. Métodos: Cinquenta e sete amostras de S. aureus provenientes de amostras de quatro tipos de fontes alimentares foram testadas por PCR com primer específico para o gene mecA e para o gene codificador da enterotoxina. Resultados: Destas, cinco (8,8 por cento do total) amostras apresentaram o gene de resistência e onze (19,2 por cento do total) continham o gene codificador da enterotoxina termolábil. Conclusão: A presença do gene de enterotoxina em produtos prontos para consumo e peixe cru de feira é uma realidade, assim como o debate sobre qual a melhor forma de se legislar sobre o assunto que deve ser mantido e melhor avaliado. Já no caso do gene de resistência, evidenciou-se que a via alimentar é sim local de circulação do gene de resistência. Também é a primeira vez que se notifica o gene mecA em alimentos prontos para consumo no Brasil e América Latina / Introduction: Staphylococcus aureus are a bacterium that causes various types of diseases. There are two major aggravating to its presence: the toxins production and antimicrobial resistance. S. aureus produce heat-labile enterotoxina that, when present in food, can lead to poisoning of those who consume. This specie is also known to easily respond adaptively to drug use becoming increasingly difficult to control it. One of the main reasons for this concern are MRSA (methicillin-resistant Staphylococcus aureus) which are resistant to betalactams drugs through a differentiated wall protein production encoded by the mecA gene. The presence of this resistant pathogen outside hospitals has been recorded a few years ago and gradually comes to discover that the food chain can be a way for the gene spread. Objectives: Search for the mecA gene and the enterotoxins encoded gene in Staphylococcus aureus from food samples to discuss the presence of the resistance gene in a new transmission route and the validity of only review the presence of Staphylococcus coagulase positive in food product as a way to keep insurance against food poisoning. Methods: Fifty-seven samples of S. aureus from five different sources of food samples were tested by PCR with specific primer for the mecA gene and the enterotoxins gene. Results: Of these, five (8,8 per cent of total) samples showed the resistance gene and eleven (19,2 per cent of total) contained the gene encoding the heat-labile enterotoxin. Conclusion: The presence of enterotoxin encoded gene in food products ready for consumption and raw fish is a fact and a debate about how best to legislate should be maintained and better evaluated. In the case of the resistance gene, the food chain is really a way where this gene can spread. It is also the first time the mecA gene from food ready for consumption is reported in Brazil and Latin America

Growth and enterotoxin production by Staphylococcus aureus straings, in the presence of different starter [2:1 (V/V) blend of AM2:ML8 strains of Streptococcus lactis] levels was investigated. Sterile, 10 per cent non-fat dry milk was inoculated with S. aureus strains capable of producing all types of enterotoxins, and reduced levels of starters; and was incubated at 32 C for 24 hours. The pH and S. aureus population were determined at 2 hour intervals until 8 hours and at 24 hours. The inhibitory response of lactic streptococci was studied by spot-tests on a lawn of S. aureus strains. The drop in pH, from 4 to 8 hours incubation, for all starter levels, was proportional to their inocula. The rate of acid formation, or drop in pH, from 4 to 8 hours, was correlated with the change in staphylococcal population from 6 to 24 hours (Correlation Coefficient = Y = -0.805). Regression analysis indicated that change in pH from 4 to 8 hours could be used to predict the staphylococcal population change from 6 to 24 hours. All four enterotoxigenic strains showed differential susceptibility to the starter metabolite(s). A 0.1 per cent starter level did not allow the increase of approximately 104 cells per milliliter, of an eterotoxin D producing strain of S. aureus (23235). Approximately 106 cells per milliliter of S. aureus 23235, decreased to about 104 cells in the presence of a 0.1 per cent starter level; while 0.01 per cent starter level did not allow the inocula of approximately 106 cells pe milliliter, of enterotoxin B producing strain of S. aureus, did not increase in the presence of 0.01 per cent starter level. The same inocula of enterotoxin A and C producing straings of S. aureus decreased to about 103 to 104 cells per milliliter in the presence of 0.01 per cent starter. These strains sharply declined in population in the presence of 0.1 per cent starter level. The lactic organism did not produce inhibitory levels nisin, or over 5 micrograms of hydrogen peroxide per milliliter of broth. When the lactic streptococci were spotted on lawns of enterotoxins B, C, and D producing strains of S. aureus, staphylococcal grothwas inhibited around the spots, on both agar, with and without added calcium carbonate. Enterotoxin A producing strain was not inhibited on agar. The degree of inhibition for B and D enterotoxin producing strains, was greater in agar fortified with calcium carbonate, than that without fortification while the revers was true for enterotoxin C producing strain.

Clostridium perfringens type A isolates producing enterotoxin (CPE) are an important cause of food poisoning and non-food-borne human gastrointestinal (GI) diseases, including antibiotic-associated diarrhea (AAD), and spontaneous diarrhea (SD). In enterotoxigenic type A isolates, the cpe gene is found on the chromosome in food poisoning isolates, but is present on a large virulence plasmid in AAD and SD type A isolates. Food poisoning cases typically exhibit shorter duration of infection and less severe GI symptoms than AAD or SD. Since previous epidemiological evidence has linked the newly discovered beta2-toxin (CPB2) to gastroenteritis in pigs, horses, and chickens, we hypothesize that the CPB2 toxin may be an accessory toxin when cpe positive type A isolates cause human AAD or SD. In the current study, the presence and expression of CPE and CPB2 were assessed in 44 C. perfringens type A human fecal isolates associated with GI diseases in the United Kingdom. Polymerase chain reaction (PCR) and restriction fragment length polymorphisim (RFLP) confirmed the presence of the cpe (32%) and cpb2 (39%) genes. Furthermore, pulsed field gel electrophoresis (PFGE) and I-CeuI RFLP PFGE Southern blot analysis was used to show the localization of the cpe and cpb2 genes, as well as to determine that there was no clonal relationship between the isolates. All surveyed cpb2-positive isolates were determined to carry their cpb2 gene on a large plasmid that was estimated to be the similar size of the cpe large plasmid. Finally, CPE and CPB2 Western blotting demonstrated that all cpe-positive isolates expressed CPE and that all cpb2-positive isolates expressed CPB2. This study identified, for the first time, the C. perfringens non-food-borne human GI disease isolates carrying both the cpe and cpb2 genes (18%), and these isolates all actively expressed both CPE and CPB2. It was also shown that, although CPE expression occurs only under sporulation conditions, CPB2 expressed both in vegetative and sporulation conditions. The CPB2 made by two of these cpe /cpb2 - positive isolates was determined to be very (-99%) similar to the deduced amino acid sequence of the biologically-active CPB2 made by the original type C isolate CWC245. Finally, the expression of CPB2 by only type A isolates carrying the cpe gene on a plasmid and not the isolates carrying a chromosomal cpe gene, could possibly explain the increased GI symptoms and disease duration associated with these non-food-borne GI diseases. Collectively, the current results support a significant association between cpb2-positive C. perfringens isolates and non-food-borne GI disease in human. / Graduation date: 2004

Recently the EPA placed Aeromonas hydrophila on the Candidate Contaminant List (CCL). It has long been known to be a pathogen of cold blooded animals and now is a suspected human opportunistic pathogen as well. Among the various virulence factors produced by A. hydrophila, the cytolytic enterotoxin (AHCYTOEN) is by far one of the most important contributors to the pathogenicity of the organism. This factor is also produced by other pathogenic Aeromonas spp. In this study, PCR technology was used to detect AHCYTOEN gene from a simulated water distribution system. A set of primers was selected to amplify the unique sequence of a pathogenic island, AHCYTOEN gene. To examine the sensitivity of the PCR, serial dilutions of pure A. hydrophila culture were tested. The PCR technique used was sensitive enough to detect samples containing less than 10.0 cells/ml. Source water, bulk water, and simulated distribution biofilm samples were examined for the gene. Biofilm and bulk water samples exposed to raw source water were collected on 4 occasions during a 24-day period. PCR technology detected the AHCYTOEN gene from 100 % of the bulk water samples and 85% of tightly bound biofilm (TB) samples from a simulated water distribution system while no positive results were observed in loosely bound biofilm samples (LB). After the inlet line of the system was changed to normally treated distribution water, 11 biofilm samples were collected on 3 occasions during 15 day sampling period along with bulk water samples. No positive results were observed from the bulk water and LB samples while 91% of TB samples tested for the presence of the gene. No significant difference was observed in detection by PCR from biofilm samples before and after the switch to chloraminated water. / Department of Biology

Diss. (sammanfattning) Stockholm : Karol inst., 2004. / Härtill 5 uppsatser.

Orientador: Helio Langoni / Banca: Márcio Garcia Ribeiro / Banca: Nilson Robeti Benites / Resumo: Alguns dos agentes patogênicos de mastite bovina são relevantes em relação à qualidade do leite, bem como, para a saúde pública. Foram estudadas dez fazendas localizadas em cinco regiões do estado de São Paulo. Foram examinadas 1.148 vacas, correspondentes a 4.592 glândulas mamárias avaliadas pelos testes de tamis e CMT. Foram colhidas 1.318 amostras de leite, das vacas positivas na triagem para avaliação microbiológica e contagem de células somáticas (CCS). A frequência dos agentes variou de 0,3 a 36,4%. Do total de isolados de Staphylococcus spp (36,4%), 48,7% corresponderam a estafilococos coagulase negativa (SCN), 34,2% S. aureus e 15,9% outros estafilococos coagulase positiva (SCP). Streptococcus spp foram isolados de 23,3% das amostras, dos quais 41,7% Streptococcus. agalactiae, 41,1% Streptococcus dysgalactiae e 17,3% Streptococcus uberis. Corynebacterium spp. foram isolados em 31,8% dos casos de mastite. As amostras de leite das glândulas mamárias infectadas apresentaram CCS significativamente mais elevada que as negativas. Dos 48,7% de SCN foram identificadas 18 espécies: S. warneri, S. epidermidis, S. hyicus, S. xylosus, S. haemolyticus, S. auriculares, S. cohnii subsp cohnii, S. lugdunensis, S. pasteuri, S. saccharolyticus, S. saprophyticus subsp bovis, S. schleiferi subsp scheleiferi, S. simulans, S. saccharolyticus, S. capitis, S. saprophyticus subsp saprophyticus, S. sciuri subsp sciuri e S. chromogenes. As fazendas, II (27,3%) e III (26,7%) apresentaram maior frequência de SCN, enquanto as fazendas I (13,3%) e X (44,4%) revelaram maior prevalência de SCP sendo as diferenças significantes. Foram avaliados por PCR 263 estafilococos para detecção de gene codificadores das enterotoxinas clássicas. Entre os SCN foram detectados: sea (35,5%) seb (7,1%), sec (6,5%), sed (1,8%) e associações destes genes. Em SCP foram detectados: sea (9,5%) seb (4,4%)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this study was to assess the occurrence of mastitis cases in ten Brazilian dairy herds located in five regions in São Paulo state, to characterize the main etiological agents and, to proceed staphylococcal isolates identification to species level, to perform detection by PCR assays of enterotoxin encoded genes aiming the awareness of their potential capability in producing the classical enterotoxins and, mecA a methicilin resistance gene and, evaluated resistance toward antimicrobials. A total of 4,592 mammary glands of 1,148 dairy cows were examined by strip cup and CMT. From these 1,318 milk samples were collected for microbiological exams. It was isolated 263 (19.9%) staphylococci from mastitis cases and they were identified, as being: S.aureus (34.2%), other CPS (15.9%) respectively, S. intermedius (15.2%), S.hyicus(12.9%) and, S. schleiferi subsp coagulans(3.8%), and CNS (48.7%). Among these 128 CNS isolates eighteen species were identified: S. xylosus, S. haemolyticus, S. auriculares; S. cohnii subsp cohnii, S. lugdunensis, S. pasteuri, S. saccharolyticus, S. saprophyticus subsp bovis, S. schleiferi subsp scheleiferi, S. simulans, S. capitis, S. saprophyticus subsp saprophyticus, S. sciuri subsp sciuri and, S. chromogenes. The more frequently isolated species were: S.warneri (31.3%), S. epidermidis (14.8%) and S.hyicus (12.5%). The milk samples from infected mammary glands showed higher CCS than the negatives. PCR assay was used to determine the presence of classical enterotoxin codifying genes (sea, seb, sec and sed). Among CNS the occurrence of enterotoxin classical genes was determined as: 35.1% for sea, 7.1% for seb, 6.5% for sec, 1.8% for sed) 5.3% for both sea and seb, 3.6% for both sea, sec and sed, 1.8% for both sec and sed. Whereas among CPS isolates the occurrence of enterotoxin... (Complete abstract click electronic access below) / Mestre

Master of Science / Department of Diagnostic Medicine/Pathobiology / Weiping Zhang / Enterotoxigenic Escherichia coli (ETEC) strains are the most common bacterial cause of diarrhea. ETEC bacterial adherence to the small intestinal epithelial cells and delivery of enterotoxins cause diarrhea in children living in developing countries and international travelers. Currently, there are no vaccines licensed for ETEC associated children’s diarrhea and travelers’ diarrhea. Recently, toxoid fusion 3xSTa[subscript N12S]-mnLT[subscript R192G/L211A] (toxoid fusion), adhesin MEFA (multiepitope fusion antigen) CFA/I/II/IV (CFA MEFA), and toxoid-adhesin MEFA CFA/I/II/IV-3xSTa[subscript N12S]-mnLT[subscript R192G/L211A] (CFA-toxoid MEFA) are demonstrated to induce neutralizing antitoxin and/or anti-adhesin antibodies in intraperitoneal (IP) or subcutaneous (SC) immunized mice, suggesting these antigens are potential candidates for ETEC subunit vaccines. However, these antigens have not been examined for immunogenicity using intradermal (ID) or intramuscular (IM) routes, the routes perhaps are more suitable for human vaccine administration. In this study, toxoid fusion 3xST[subscript aN12S]-mnLT[subscript R192G/L211A], CFA/I/II/IV MEFA, alone or combined, or toxoid-adhesin MEFA CFA-3xSTa[subscript N12S]-mnLT[subscript R192G/L211A] were ID or IM immunized to mice (8 mice per group) induced antigen-specific antibodies were titrated, and antibody neutralization activities were assessed in vitro. Data showed that mice ID or IM immunized with the toxoid fusion 3xSTa[subscript N12S]-mnLT[subscript R192G/L211A] antigen developed anti-LT and anti-STa antibodies and mice immunized with the CFA/I/II/IV MEFA developed antibody responses to all seven adhesins (CFA/I, CS1-CS6). In addition, mice co-administered ID or IM with toxoid fusion 3xSTa[subscript N12S]-mnLT[subscript R192G/L211A] and CFA/I/II/IV MEFA, or with toxoid-adhesin MEFA CFA-3xSTa[subscript N12S]-mnLT[subscript R192G/L211A] developed antibodies to both toxins and all seven adhesins. Antibody neutralization studies of the serum samples of the immunized mice showed that the induced antibodies neutralized enterotoxicity of LT and STa and/or inhibited adherence of ETEC or E. coli bacteria producing any of these seven adhesins. These data confirmed immunogenicity of these ETEC subunit vaccine target antigens and provide useful information for vaccine development against ETEC diarrhea.

Os produtos de origem animal, produzidos em indústrias brasileiras e inspecionados pelo Serviço de Inspeção Federal, passam por diversos controles, em todas as etapas do seu processamento. Após a industrialização, são submetidos a análises em laboratórios oficiais, para verificação do cumprimento de parâmetros que os definem como aceitáveis ao consumo e isentos de risco. Uma das análises realizadas rotineiramente é a enumeração de Staphylococcus aureus (S. aureus). Este microrganismo possui um risco associado a sua presença em grande número, pois alguns deles têm a capacidade de produzir, sob determinadas condições, enterotoxinas termoestáveis, que, ao serem ingeridas, juntamente com o alimento, produzem uma enfermidade. A proposta deste trabalho foi estudar a distribuição das cepas de S. aureus isoladas de amostras de produtos de origem animal das regiões sul, sudeste, norte e nordeste do Brasil e caracterizá-las, com objetivo de estimar riscos de transmissão, através dos alimentos, de cepas resistentes aos antimicrobianos normalmente utilizados em tratamentos de infecções estafilocócicas e investigar a capacidade destas de produzirem as chamadas "enterotoxinas clássicas" (SEA, SEB, SEC, SED e SEE). Os isolados bacterianos foram originários de 3.748 amostras de diversos produtos de origem animal, que foram analisadas em laboratórios oficiais do Ministério da Agricultura, Pecuária e Abastecimento (MAPA), no período de 2003 e 2004. Duzentos e quarenta e cinco cepas de S. aureus, com diversas quantificações, foram isoladas e caracterizadas fenotipicamente, através de critérios estabelecidos como padrões nas análises do MAPA e através de outros complementares, para certificação de que se tratavam mesmo de S. aureus. Os isolados obtidos foram submetidos ao ensaio imunoenzimático automatizado (ELFA - Enzyme-linked Fluorescent Assay - VIDAS®Staph enterotoxin II SET2), para detectar a capacidade de produzirem quantidades detectáveis das cinco enterotoxinas clássicas (SEs). Entre os isolados positivos no ensaio imunoenzimático, determinou-se a freqüência de amplificação, pela Reação em Cadeia da Polimerase, de cada um dos genes respectivos (sea, seb, sec, sed e see). Posteriormente, foi realizado estudo das resistências dos isolados de S. aureus frente a 17 antimicrobianos de importância clínica, pelo método da difusão em ágar. Os isolados foram agrupados de acordo com os perfis de amplificação dos genes das enterotoxinas e pelos perfis de resistência aos antimicrobianos, correlacionando-os com os tipos de alimentos e as regiões nas quais foram encontrados. Oitenta e um isolados produziram quantidades detectáveis de enterotoxinas. Os genes mais freqüentemente encontrados foram o seb e o sec-1 (ambos com 76,54%), seguidos do sea (61,73%). Apenas quatro dos isolados produtores de enterotoxinas clássicas (três originários de queijo de coalho e um de bacon) apresentaram contagens >105. Em cinqüenta e nove cepas (72,84%) houve amplificação de múltiplos genes que codificam enterotoxinas (A-E). Com relação às 81 cepas que produziram enterotoxinas em caldo de cultivo, observou-se que 63 (77,8%) eram provenientes de produtos cárneos, 11 (13,6%) de produtos lácteos, três (3,7%) de pescados e quatro (4,9%) de outros produtos de origem animal. Cinco eram da região norte, quatro da região nordeste, 19 da região sul e 53 da região sudeste. O grupo formado pelo perfil sea, seb e sec combinados foi o mais freqüente, com 33 isolados. Vinte e seis cepas deste grupo eram originárias da região sudeste, cinco da região norte e dois da região sul. Oitenta e oito cepas não apresentaram nenhuma resistência aos antimicrobianos testados. As resistências mais freqüentes foram frente à penicilina, norfloxacina, canamicina e tetraciclina. Foram formados 64 perfis diferentes de resistência. O perfil mais freqüente foi resistência à penicilina, unicamente, seguido de resistência à penicilina/canamicina. A partir dos resultados deste trabalho, pode-se concluir que o risco de estarem presentes enterotoxinas nos alimentos de origem animal que passam por processos de industrialização controlados e acompanhados pelo Serviço Oficial de Inspeção brasileiro é muito baixo, (somente quatro das 3.748 amostras) Entretanto, uma vez que foram detectados diversos perfis de resistência a antimicrobianos nos isolados de Staphylococcus aureus obtidos, a possibilidade de veiculação e disseminação dessas cepas resistentes, através de alimentos de origem animal, pode existir e deve ser monitorada. / Food from animal origin produced at Brazilian industries and inspected by the Federal Inspection Service suffer many controls in all stages of their processing. After the industrialization, they are tested in official laboratories for verification of the parameters which define them as acceptable for consumption and free of risk. One of the tests routinely carried out is the Staphylococcus aureus (S. aureus) enumeration. These microorganism have a risk associated with their presence in large numbers. Some of them have the capacity to produce, under certain conditions, heat-stable staphylococcal toxins. If they are ingested with food, they will produce foodborne disease. The aim of this report was to study the distribution and feature of S. aureus strains isolated from food animal origin products, in order to estimate risks of transmission of resistant strains to antibiotics commonly used in treatment of staphylococcal infections through food and to investigate their ability to produce so-called "classical enterotoxins" (SEA, SEB, SEC, SED and SEE). The food samples tested were from different regions of Brazil (south, southest, north and northeast). From a total of 3,748 food samples, analized in official laboratories from Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento - MAPA) between 2003 and 2004, 245 presented different counts of S. aureus. They were isolated and characterized phenotypically, using analysis criteria established by the MAPA and through others complementary tests, for guarantee that they are really S. aureus. The isolates were submited to automated immunoassay method (Enzyme-Linked Fluorescent Assay - VIDAS®Staph enterotoxin II SET2) for detection of the strains ability to produce detectable quantities of the five classical enterotoxins (SEs). Among the positive strains in enzyme immunoassay, it was determinate the frequency of amplification, by Polymerase Chain Reaction (PCR), of each of the respective genes (sea, seb, sec-1, sed and see). Subsequently, it was studied S. aureus resistance, by the diffusion in agar method, to 17 clinical importance antimicrobials. The strains were grouped according to the enterotoxin genes and the antimicrobial resistance profiles, correlating them with the types of food and regions which they have been found. Eighty-one strains produced detectable amounts of enterotoxins. The most frequent genes found in those strains were seb and sec-1 (both with 76.54%), followed by sea (61.73%). Only four enterotoxin producer strains presented counts >105 (three samples of Brazilian cottage-like cheese - "queijo de coalho", and one sample of bacon). In 59 isolates (72.84%) it was observed an amplification of multiple genes encoding enterotoxins (A-E). In relation to the 81 strains that produced enterotoxins in culture broth, we observed that 63 (77.8%) came from meat products, 11 (13.6%) were samples of milk products, three (3.7%) were fish, and four (4.9%) were others products of animal origin. Five samples were from the North, four from the Northeast, 19 from the South and 53 from the Southeast region of Brazil. The most frequent profile was found in 33 strains, and was composed by sea, seb, and sec genes. Twenty-six strains of this group were from Sutheast, five from North and two from South Region. Eighty-eight strains did not show any resistance to antimicrobial tested. The highest resistance frequency was observed against penicillin, norfloxacin, kanamycin and tetracycline. Sixty four different resistance profiles could be identified. The profile resistance to penicillin, follow by the profile to penicillin/kanamycin, were the most prevalent. From these results, it is possible to conclude that the risk of having pre-formed enterotoxins in animal derived food items that go through an industrial process, controlled by the Brazilian Official Inspection Service, is very low (only four of 3,748 samples). However, the identification of resistance profiles was detected in S. aureus strains. The possibility of transmission and distribution of these resistant strains through food of animal origin can exist and should be monitored.