927 resultados para Bacterial infections and mycoses


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Salmonellosis is a worldwide disease caused by bacteria of the genus Salmonella. Currently, there are over 2,500 identified serovars of Salmonella. A reduced number of these serovars, about eighty, are implicated in most animals and human diseases. Most cases of salmonellosis in humans are associated with the consumption of contaminated food products such as beef, pork, poultry meat, eggs, vegetables, juices and other kind of foods. It may also be associated with the contact between humans and infected pet animals. Therefore, the chain of human salmonellosis is very complex and in most cases the origin of the infection is difficult to establish. The use of antimicrobial agents to treat and to prevent bacterial infections in humans and animals, as well as as growth promoters in animal production, has favoured the selection and transference of resistance genes between different bacteria, including Salmonella serovars. Many studies have confirmed the role of foods of animal origin as a source of multi drugresistant Salmonella serovars. For this reason, continuous surveillance of these pathogens along the food chain together with the responsible use of antimicrobial agents is necessary.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Owing to their massive use, Staphylococcus epidermidis has recently developed significant resistance to several antibiotics, and became one of the leading causes of hospital-acquired infections. Current antibiotics are typically ineffective in the eradication of bacteria in biofilm-associated persistent infections. Accordingly, the paucity of effective treatment against cells in this mode of growth is a key factor that potentiates the need for new agents active in the prevention or eradication of biofilms. Daptomycin and linezolid belong to the novel antibiotic therapies that are active against gram-positive cocci. on the other hand, rifampicin has been shown to be one of the most potent, prevalent antibiotics against S. epidermidis biofilms. Therefore, the main aim of this study was to study the susceptibility of S. epidermidis biofilm cells to the two newer antimicrobial agents previously mentioned, and compare the results obtained with the antimicrobial effect of rifampicin, widely used in the prevention/treatment of indwelling medical device infections. To this end the in vitro activities of daptomycin, linezolid, and rifampicin on S. epidermidis biofilms were accessed, using these antibiotics at MIC and peak serum concentrations. The results demonstrated that at MIC concentration, rifampicin was the most effective antibiotic tested. At peak serum concentration, both strains demonstrated similar susceptibility to rifampicin and daptomycin, with colony-forming units (CFUs) reductions of approximately 3-4 log(10), with a slightly lower response to linezolid, which was also more strain dependent. However, considering all the parameters studied, daptomycin was considered the most effective antibiotic tested, demonstrating an excellent in vitro activity against S. epidermidis biofilm cells. In conclusion, this antibiotic can be strongly considered as an acceptable therapeutic option for S. epidermidis biofilm-associated infections and can represent a potential alternative to rifampicin in serious infections where rifampicin resistance becomes prevalent.

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As infecções devido a biofilmes bacterianos são comuns em pacientes sob tratamento em hemodiálise. Neste estudo, 16 pacientes (7 homens, 9 mulheres, de 22 a 81 anos, média 50 anos de idade), com um total de 25 cateteres de hemodiálise (3 de triplo-lúmen e 22 de duplo-lúmen) de poliuretano inseridos em veia subclávia foram estudados. Os cateteres permaneceram no local de 3 a 91 dias (média de 47 dias). Os cateteres foram removidos devido ao: mau funcionamento (44%), suspeita de infecção relacionada ao cateter (20%), viabilidade de um acesso permanente (16%), remoção acidental (12%), sinais e sintomas de infecção no local da inserção do cateter (4%) e contaminação exógena (4%). Culturas positivas de ponta foram observadas em sete cateteres (28%), concomitantemente com três culturas positivas de sangue. Das culturas de sangue foram identificados Staphylococcus aureus (12%) e de uma das conexões foi isolado S. aureus. Biofilmes foram observados sobre todas as pontas de cateteres. Os S. aureus isolados do sangue e cateter (ponta e conexão) eram resistentes a pencilina e sensíveis a azitromicina, ciprofloxacina, clindamicina, cloranfenicol, gentamicina, oxacilina, rifampicina, sulfametoxazole, tetraciclina e vancomicina. As cepas de S. aureus isoladas de sangue, ponta de cateter e conexão foram consideradas idênticas devido à coincidência do perfil de sensibilidade. E similaridade genética, avaliada por meio de ribotipagem.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Bacterial meningitis (BM) is still an important infectious disease causing death and disability. Invasive bacterial infections of the central nervous systems (CNS) generate some of the most powerful inflammatory responses known, which contributes to neuronal damage. The DNA microarray technology showed alterations in the kynurenine (KYN) pathway that is induced in BM and other diseases associated with inflammation, leading to brain injury. Our main aim was to search SNPs previously described in the KYN path enzymes to investigate a putative association of this SNPs with imbalanced in this pathway in patients with BM. The patients included in this study were 33 males and 24 females, with ages varying from 02 months to 68 years. SNPs were located inside of the domain conserved in KYNU, IDO, KATI and KATII. Primers were designed for analysis of SNPs already described by PIRA-PCR followed by RFLP. The analysis of KYNU+715G/A SNP found a heterozygous frequency of 0.033. We did not found the variant allele of SNP KYNU+693G/A, KATI+164T/C, KATII+650C/T and IDO+434T/G. Despite of previews studies showing the importance of KYN pathway we did not found one association of these SNPs analyzed with susceptibility or severity of MB in study population.

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Cold atmospheric plasma treatment of microorganisms and living tissues has become a popular topic in modern plasma physics and in medical science. The plasma is capable of bacterial inactivation and noninflammatory tissue modification, which makes it an attractive tool for treatment of skin diseases, open injuries and dental caries. Because of their enhanced plasma chemistry, Dielectric Barrier Discharges (DBDs) have been widely investigated for some emerging applications such as biological and chemical decontamination of media at ambient conditions. Despite the high breakdown voltage in air at atmospheric pressure, the average current of DBD discharges is low. Therefore, a DBD can be applied in direct contact with biological objects without causing any damage. In this work a 60 Hz DBD reactor, which generates cold atmospheric plasma inside Petri dishes with bacterial culture, is investigated. Samples of Staphylococcus aureus, a Gram-positive bacterium and Escherichia coil a Gram-negative bacterium were selected for this study. The bacterial suspensions were evenly spread on agar media planted in Petri dishes. The reactor electrodes were placed outside the Petri dish, thus eliminating the risk of samples microbial contamination. The covered Petri dish with agar medium in it serves as dielectric barrier during the treatment. The plasma processing was conducted at same discharge power (similar to 1.0 W) with different exposure time. Sterilization of E. coil and S. aureus was achieved for less than 20 min. Plasma induced structural damages of bacteria were investigated by Scanning Electron Microscopy. (C) 2010 Elsevier B.V. All rights reserved.

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Hemicelluloses are polysaccharides of low molecular weight containing 100 to 200 glycosidic residues. In plants, the xylans or the hemicelluloses are situated between the lignin and the collection of cellulose fibers underneath. The xylan is the most common hemicellulosic polysaccharide in cell walls of land plants, comprising a backbone of xylose residues linked by beta-1,4-glycosidic bonds. So, xylanolytic enzymes from microorganism have attracted a great deal of attention in the last decade, particularly because of their biotechnological characteristics in various industrial processes, related to food, feed, ethanol, pulp, and paper industries. A microbial screening of xylanase producer was carried out in Brazilian Cerrado area in Selviria city, Mato Grosso do Sul State, Brazil. About 50 bacterial strains and 15 fungal strains were isolated from soil sample at 35 A degrees C. Between these isolated microorganisms, a bacterium Lysinibacillus sp. and a fungus Neosartorya spinosa as good xylanase producers were identified. Based on identification processes, Lysinibacillus sp. is a new species and the xylanase production by this bacterial genus was not reported yet. Similarly, it has not reported about xylanase production from N. spinosa. The bacterial strain P5B1 identified as Lysinibacillus sp. was cultivated on submerged fermentation using as substrate xylan, wheat bran, corn straw, corncob, and sugar cane bagasse. Corn straw and wheat bran show a good xylanase activity after 72 h of fermentation. A fungus identified as N. spinosa (strain P2D16) was cultivated on solid-state fermentation using as substrate source wheat bran, wheat bran plus sawdust, corn straw, corncob, cassava bran, and sugar cane bagasse. Wheat bran and corncobs show the better xylanase production after 72 h of fermentation. Both crude xylanases were characterized and a bacterial xylanase shows optimum pH for enzyme activity at 6.0, whereas a fungal xylanase has optimum pH at 5.0-5.5. They were stable in the pH range 5.0-10.0 and 5.5-8.5 for bacterial and fungal xylanase, respectively. The optimum temperatures were 55C and 60 A degrees C for bacterial and fungal xylanase, respectively, and they were thermally stable up to 50 A degrees C.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The immune response to leishmaniasis can result in a polarization of a subpopulation of T lymphocytes, which leads to a different cell phenotype and results in immune protection or exacerbation of the disease. Leishmanias persist in the body both in asymptomatic infections and after treatment, representing risks in terms of immunosuppression. The objective of this study was to evaluate the effects of infection and immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, the parasitic load in the spleen and liver, as well as the production of IFN-gamma and IL-10 in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not alter animal weight gain, but spleen weight and size increased. The immunosuppression, induced by dexamethasone associated with pentoxifylline, affected animal weight gain and weight and size of the spleen (in infected and not infected animals). The immunosuppression did not significantly alter the course of the parasite burden in the spleen and liver. Dexamethasone and pentoxifylline affected the studied cytokine production, but not influenced on Th1/Th2 response in infected animals.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)