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Caracterização fenotípica e genética de resistência antimicrobiana em salmonella enterica
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Abstract(s)
O género Salmonella, pertence à família Enterobacteriaceae e consiste em bacilos Gram- negativos, não formadores de esporos. As bactérias que constituem o género contêm três tipos diferentes de antigénios. As propriedades aglutinantes dos antigénios somáticos (O), flagelar (H) e capsular (Vi), são usados para diferenciar sorologicamente através do esquema de White-Kauffman-Le Minor, os diversos sorovares e assim classificar o género em duas espécies bacterianas, Salmonella enterica e Salmonella bongori, sendo que a primeira é dividida em seis subespécies: enterica, salamae, arizonae, diarizonae, houtenae e indica.
Ao longo dos anos esta bactéria de origem alimentar desenvolveu vários mecanismos moleculares através de genes de resistência a antibióticos, frequentemente associados a elementos genéticos móveis, que promovem a sua mobilidade, permitindo que eles se espalhem rapidamente no ambiente. A crescente taxa de resistência aos antibióticos em Salmonella, representa uma preocupação global significativa, muito pelo surgimento de estirpes multirresistentes e extensivamente resistentes. Desta forma, é essencial uma melhor compreensão dos mecanismos de resistência a antibióticos em Salmonella, para a escolha do antibiótico adequado no tratamento de infeções.
Nesta dissertação, identificaram-se os mecanismos de disseminação de genes de resistência e de que modo estes influenciam a ação da bactéria na presença de diferentes classes de antibióticos. Concluiu-se que a existência de métodos genotípicos para caracterização de Salmonella, em particular a sequenciação do genoma completo, são fulcrais para entender os processos que estão na base da resistência a antibióticos.
The Salmonella genus belongs to the Enterobacteriaceae family and consists of Gram- negative, non spore forming bacilli. The bacteria that make up the genus contain three different types of antigens. The agglutinating properties of the somatic (O), flagellar (H) and capsular (Vi) antigens are used to serologically differentiate through the White- Kauffman-Le Minor scheme, the various serovars and thus classify the genus into two bacterial species, Salmonella enterica and Salmonella bongori, the former being divided into six subspecies: enterica, salamae, arizonae, diarizonae, houtenae and indica. Over the years, this food-borne bacterium has developed several molecular mechanisms through antibiotic resistance genes, often associated with mobile genetic elements, which promote its mobility, allowing it to spread rapidly in the environment. The increasing rate of antibiotic resistance in Salmonella represents a significant global concern, largely due to the emergence of multidrug-resistant and extensively resistant strains. In this way, a better understanding of the mechanisms of antibiotic resistance in Salmonella is essential, for the choice of the appropriate antibiotic in the treatment of infections. In this dissertation, we identified the mechanisms of dissemination of resistance genes and how they influence the action of bacteria in the presence of different classes of antibiotics. It was concluded that the existence of genotypic methods for characterizing Salmonella, in particular the sequencing of the complete genome, are essential to understand the processes that underlie antibiotic resistance.
The Salmonella genus belongs to the Enterobacteriaceae family and consists of Gram- negative, non spore forming bacilli. The bacteria that make up the genus contain three different types of antigens. The agglutinating properties of the somatic (O), flagellar (H) and capsular (Vi) antigens are used to serologically differentiate through the White- Kauffman-Le Minor scheme, the various serovars and thus classify the genus into two bacterial species, Salmonella enterica and Salmonella bongori, the former being divided into six subspecies: enterica, salamae, arizonae, diarizonae, houtenae and indica. Over the years, this food-borne bacterium has developed several molecular mechanisms through antibiotic resistance genes, often associated with mobile genetic elements, which promote its mobility, allowing it to spread rapidly in the environment. The increasing rate of antibiotic resistance in Salmonella represents a significant global concern, largely due to the emergence of multidrug-resistant and extensively resistant strains. In this way, a better understanding of the mechanisms of antibiotic resistance in Salmonella is essential, for the choice of the appropriate antibiotic in the treatment of infections. In this dissertation, we identified the mechanisms of dissemination of resistance genes and how they influence the action of bacteria in the presence of different classes of antibiotics. It was concluded that the existence of genotypic methods for characterizing Salmonella, in particular the sequencing of the complete genome, are essential to understand the processes that underlie antibiotic resistance.
Description
Keywords
Resistência Salmonella Transferência horizontal genes Subtipagem Salmonella Febre tifoide Salmonelose Salmonella resistance Horizontal gene transfer Salmonella subtyping Typhoid fever Salmonellosis