Antimicrobial resistance and R-plasmid in Salmonella spp from swine and abattoir environments

Salmonella serovars isolated from swine are of particular interest not only because of the pathogenic potential for this animal species, but also due to its relevance with regard to public health. On basis of the profile of resistance to antimicrobials, 13 Salmonella strains were selected which belonged to the serovars Muenster (7), Derby (4), Typhimurium (1), and Braenderup (1). They were isolated from healthy swine as well as from the abattoir environment in the state of Rio de Janeiro. All strains of Salmonella were subjected to bacterial conjugation, and the E. coli K12 Nal r Lac+ F standard strain was used as receptor, with the purpose to verify the ability to transfer the resistance marks. Gene transfer phenomenon was detected in seven strains, and except SalmonellaTyphimurium which transconjugated to Sm, Tc and Su, the remaining ones were characterized by transferring mark Su only. By plasmidial analysis of strains used and their respective transconjugants, 63 Kb plasmid was found, which was probably related to S. Typhimurium resistance. Sorovares de Salmonella isolados de suinos são de particular interesse não só pelo potencial patogênico para esta espécie animal, como também pela sua relevância em Saúde Pùblica. Com base no perfil de resistência aos antimi-crobianos foram selecionadas 13 amostras de Salmonella pertencentes aos sorovares Muenster (7 amostras), Derby (4), Typhimurium (1) e Braenderup (1), isoladas de suinos sadios e do ambiente de abatedouro no Estado do Rio de Janeiro. As amostras foram submetidas a conjugação bacteriana, utilizando como receptora E.coli K12 55 Nal r Lac+ F -, com a finalidade de verificar a capacidade da transferência de marcos de resistência. O fenômeno de transferência gênica foi detectado em 7 amostras e, com exceção de Salmonella Typhimurium que transconjugou para Sm, Tc e Su, as demais se caracterizaram por transferir somente o marco Su. Na análise plasmidial das amostras doadoras e suas respectivas transconjugantes foi revelado um plasmídio de 63 Kb, provavelmente relacionado com a multirresistência de S. Typhimurium.