Detecção de Salmonella spp por meio da reação em cadeia da polimerase (PCR) em ovos comercializados em Fortaleza, Ceará

The egg is an inexpensive and highly nutritious food that is part of the Brazilian food habits. However, eggs are one of the most important causative agents of salmonellosis, diseases caused by bacteria of the genus Salmonella, belonging to the family Enterobacteriaceae, of which there are more than 2,500 serotypes; however, 80-90 are important to the health of animals and humans. Therefore, the aim of this study was to evaluate the level of contamination by Salmonella spp. in quail and chicken eggs (shell and yolk) commercialized in Fortaleza/CE by a specific polymerase chain reaction (PCR). The shell and yolk of 36 egg were analyzed by PCR using specific primers that amplify a fragment of 284 base pairs (bp) from the invA gene of Salmonella thyfimurium. The results show that 2.6% of the yolks and 5.3% shells were positive for Salmonella. Comparing the different types of eggs, 11.1% of the white type were positive in shell for Salmonella, 7.1% of the yolk from quail eggs were positives and no contamination was detected in red eggs. In conclusion, the PCR was effective to demonstrate that chicken and quail eggs sold in Fortaleza-CE showed salmonella contamination.O ovo é um alimento econômico e de alto valor nutritivo que faz parte do hábito alimentar do povo brasileiro. Entretanto, é um dos principais agentes causadores de salmonelose, enfermidade provocada por bactérias do gênero Salmonella, pertencentes à família Enterobacteriaceae, sendo conhecidos mais de 2.500 sorotipos, dos quais 80 a 90 têm importância para a saúde de animais e seres humanos. Diante dessa problemática, o presente trabalho teve como objetivo avaliar o nível de contaminação por Salmonella spp. em ovos de galinha e codorna (casca e gema) comercializados em Fortaleza/CE, por meio da técnica de PCR. Foram analisadas amostras de casca e gema de 36 ovos dos tipos branco, vermelho e codorna por reação em cadeia da polimerase (PCR), utilizando oligonucleotídeos específicos que conseguem amplificar um fragmento de 284 pares de bases (bp) do gene invA de Salmonella thyfimurium. Os resultados mostram que 2,6% da parte interna dos ovos e 5,3% da casca foram positivos para salmonela. Na comparação entre os diferentes tipos de ovos, das 18 amostras de ovos brancos, 11,1% apresentaram positividade na casca para Salmonella; das 14 de ovos de codorna, cerca de 7,1% das gemas apresentavam-se positivas e os ovos vermelhos apresentaram ausência de contaminação. Conclui-se que a técnica de PCR foi eficiente para demonstrar que ovos de galinha e codorna comercializados na cidade de Fortaleza-CE apresentaram contaminação por salmonela

IFN-γ-induced priming maintains long-term strain-transcending immunity against blood-stage Plasmodium chabaudi malaria

The mechanism by which protective immunity to Plasmodium is lost in the absence of continued exposure to this parasite has yet to be fully elucidated. It has been recently shown that IFN-γ produced during human and murine acute malaria primes the immune response to TLR agonists. In this study, we investigated whether IFN-γ-induced priming is important to maintain long-term protective immunity against Plasmodium chabaudi AS malaria. On day 60 postinfection, C57BL/6 mice still had chronic parasitemia and efficiently controlled homologous and heterologous (AJ strain) challenge. The spleens of chronic mice showed augmented numbers of effector/effector memory (TEM) CD4(+) cells, which is associated with increased levels of IFN-γ-induced priming (i.e., high expression of IFN-inducible genes and TLR hyperresponsiveness). After parasite elimination, IFN-γ-induced priming was no longer detected and protective immunity to heterologous challenge was mostly lost with >70% mortality. Spontaneously cured mice had high serum levels of parasite-specific IgG, but effector T/TEM cell numbers, parasite-driven CD4(+) T cell proliferation, and IFN-γ production were similar to noninfected controls. Remarkably, the priming of cured mice with low doses of IFN-γ rescued TLR hyperresponsiveness and the capacity to control heterologous challenge, increasing the TEM cell population and restoring the CD4(+) T cell responses to parasites. Contribution of TLR signaling to the CD4(+) T cell responses in chronic mice was supported by data obtained in mice lacking the MyD88 adaptor. These results indicate that IFN-γ-induced priming is required to maintain protective immunity against P. chabaudi and aid in establishing the molecular basis of strain-transcending immunity in human malaria.São Paulo Research Foundation (FAPESP) - 471869/2010-4São Paulo Research Foundation (FAPESP) - 2011/24038-1Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) - 2009/08559-