Rastreamento e caracterização de Salmonella spp. em indústrias de processamento de carne bovina e açougues localizados em Minas Gerais, Brasil

• Autor(a) principal: Cossi, Marcus Vinícius Coutinho
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1476
• topic: Microbiologia veterinária; Salmonella; Bovino - Carcaças; Alimentos; Açougues; Contaminação microbiana; Veterinary microbiology; Salmonella; Cattle - Housing; Food; Butchers; Microbial contamination; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::INSPECAO DE PRODUTOS DE ORIGEM ANIMAL

As Salmonella spp is still one of the most important foodborne pathogen related to public health, the aim of this study was to identify the contamination routs in beef chain production, through the identification of the pathogen in critical points of contamination on slaughterhouses and butcher shops. 3 slaughterhouses located in Minas Gerais state, Brazil, were considered in this study to obtain 209 carcasses samples in 4 steps of the slaughtering (bovine hide; after skinning, after evisceration and after the end wash). Also, samples were obtained from 4 butcher shops located in Viçosa, Minas Gerais, Brazil. On these facilities, 32 samples were obtained from each of the utensils: employees hands, cutting boards, knives, refrigeration rooms, meat grinders and meat tenderizers. Salmonella spp isolates were submitted to DNA macrorestriction (XbaI) and pulse field gel electrophoresis. Also, virulence genes and antimicrobial resistance were tested. Salmonella was identified from hide of 6 animals, 1 carcass after skinning, 2 carcasses after evisceration and 3 carcasses after end wash. These isolates were confirmed as serotypes Dublin, Derby, Infantis, Give and Salmonella enterica subsp. salamae. PFGE analysis of the 20 isolates showed the occurrence of cross contamination between slaughterhouses and also between steps of the slaughtering. This result shows the low occurrence of Salmonella spp in slaughterhouse in Minas Gerais state, Brazil, and also the possible routs of contamination. At the butcher shops, 5 cutting boards were positive for Salmonella spp. From these positive samples, 15 isolates were obtained with 4 different pulsotypes after PFGE analysis. The virulence gene invA was present in 13 isolates, the gene sefA was present in 8 isolates. All the isolates showed resistance for clindamycin, sensibility for amikacin and cefotaxime and all presented resistance to at least 3 tested antimicrobial profiles. This result shows the importance of the cutting board as a contamination route for Salmonella spp. and the presence of virulence genes and multidrug resistance highlight the importance of Salmonella spp. for the public health. Finally, the serotypes and pulsotypes from the isolates obtained on the slaughterhouses were compared to the virulence genes and antimicrobial resistance profiles. The virulence genes tested were located in three different genomic regions: pathogenic island (Group 1), plasmids (Group 2) and other DNA sites (Group 3). The analysis of this results showed that all the isolates from the same pulsotype had the same serotype. Also, virulence genes of the Group 1 and 2 showed to be very conserved between isolates from the same pulsotype. Antimicrobial resistance profiles also showed to be very conserved in isolates belonging to the same pulsotype, enhancing how the use of genotype and phenotype techniques can be helpful on Salmonella spp grouping. As a conclusion, besides the low occurrence of Salmonella spp in carcasses and environment handling foods, the presence of virulence genes and multidrug resistance shows how Salmonella spp is still an important foodborne pathogens associate with contaminated food. This study also shows how the association of genotype and phenotype technique can be greatly helpful during outbreaks investigation.