Avaliação da infecção de pintainhos de corte por Salmonella Heidelberg contendo deleção no gene ttra, ttrapdua e ttracbs
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Data
2022-12-20
Autores
Goes, Vinicius
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Universidade Estadual Paulista (Unesp)
Resumo
Salmonella Heidelberg (SH) é uma enterobactéria que pode afetar frangos comerciais, ocasionando prejuízos econômicos relevantes na avicultura, além de ser uma séria preocupação para a saúde pública em escala global. Após a colonização do intestino, Salmonella spp. faz uso de mecanismos associados às Ilhas de Patogenicidade (SPI), modificando o microambiente, e consequentemente induzindo uma resposta inflamatória benéfica para sua sobrevivência. A indução da inflamação, desencadeia a produção do tetrationato que é utilizado como aceptor de elétrons, promovendo novas fontes de carbono em ambiente anaeróbio e, assim, favorendo a multiplicação dessa bactéria. Para utilizar o tetrationato, Salmonella spp. necessita da expressão de genes específicos localizados na SPI-1 e 2, como o ttr, pduA e ttrACBS. Diante do exposto, esse estudo teve como objetivo investigar as consequências da deleção dos genes ttrA, pduA e ttrACBS na infecção de frangos de corte por SH. Foram construídas estirpes de SH mutante (SHΔttrA, SHΔttrApduA e SHΔttrACBS) e sua habilidade em colonizar o intestino das aves e ser excretada foi comparada à estirpe selvagem em dois experimentos. No primeiro foi avaliada a excreção fecal das quatro estirpes por 28 dias após a infecção (dpi), sendo que as estirpes SHΔttrA e SHΔttrApduA apresentaram maior excreção. No segundo experimento, a colonização cecal foi avaliada aos dois, cinco, sete, 14, 21 e 28 dpi, sendo que a estirpe SHΔttrA foi mais isolada aos 21 e 28 dpi, SHΔttrApduA foi menos isolada nos dois e sete dpi e a estirpe SHΔttrACBS não obteve diferenças estatísticas até os 28 dpi, na qual foi menos isolada nesse dia. Os resultados sugerem que mesmo sem a utilização do gene ttrA, ttrApduA e operon ttr, SH ainda foi capaz de colonizar o intestino da ave, possivelmente utilizando uma via alternativa para utilização de aceptores de elétrons.
Salmonella Heidelberg (SH) is a enterobacterium that can affect commercial birds, causing significant economic losses in poultry industry, besides being a serious concern for public health on a global scale. After colonization of the intestine, Salmonella spp. makes use of mechanisms associated with Salmonella Pathogenicity Islands (SPI), modifying the microenvironment and consequently inducing an inflammatory response that is beneficial for its surveillance. The inflammation’s induction triggers the production of tetrathionate, which is used as an electron acceptor, promoting new sources of carbon in an anaerobic environment, which favors the multiplication of this bacterium. To utilize the tetrathionate, Salmonella spp. requires the expression of specific genes located in SPI-1 and 2, such as ttrA, pduA and ttrACBS. Therefore, this study aimed to investigate the consequences of the ttrA, pduA and ttrACBS genes deletion in the infection of broilers by SH. Mutant SH strains (SHΔttrA, SHΔttrApduA and SHΔttrACBS) was constructed, compared to wild-type infection, in two experiments. In the first one, fecal excretion was evaluated during 28dpi and the SHΔttrA and SHΔttrApduA strain was more excreted than the wild type. In the second, cecal colonization was evaluated at two, five, seven, 14, 21 and 28dpi and SHΔttrA was more isolated at 21 and 28 dpi, SHΔttrApduA was less isolated at two and sevem dpi and SHΔttrACBS did not has statistical differences up to 28 dpi, where it was less isolated on that day. The results suggest that even without the expression of the ttrA ttrApduA and operon ttr genes, SH is still able to stimulate intestinal inflammation and uses an alternative path of pathogenicity in the use of electron acceptors, conferring an advantage.
Salmonella Heidelberg (SH) is a enterobacterium that can affect commercial birds, causing significant economic losses in poultry industry, besides being a serious concern for public health on a global scale. After colonization of the intestine, Salmonella spp. makes use of mechanisms associated with Salmonella Pathogenicity Islands (SPI), modifying the microenvironment and consequently inducing an inflammatory response that is beneficial for its surveillance. The inflammation’s induction triggers the production of tetrathionate, which is used as an electron acceptor, promoting new sources of carbon in an anaerobic environment, which favors the multiplication of this bacterium. To utilize the tetrathionate, Salmonella spp. requires the expression of specific genes located in SPI-1 and 2, such as ttrA, pduA and ttrACBS. Therefore, this study aimed to investigate the consequences of the ttrA, pduA and ttrACBS genes deletion in the infection of broilers by SH. Mutant SH strains (SHΔttrA, SHΔttrApduA and SHΔttrACBS) was constructed, compared to wild-type infection, in two experiments. In the first one, fecal excretion was evaluated during 28dpi and the SHΔttrA and SHΔttrApduA strain was more excreted than the wild type. In the second, cecal colonization was evaluated at two, five, seven, 14, 21 and 28dpi and SHΔttrA was more isolated at 21 and 28 dpi, SHΔttrApduA was less isolated at two and sevem dpi and SHΔttrACBS did not has statistical differences up to 28 dpi, where it was less isolated on that day. The results suggest that even without the expression of the ttrA ttrApduA and operon ttr genes, SH is still able to stimulate intestinal inflammation and uses an alternative path of pathogenicity in the use of electron acceptors, conferring an advantage.
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Palavras-chave
Patologia veterinária, Avicultura, Salmonella, Saúde pública veterinária, Medicina veterinária