Caracterização molecular e da virulência de cepas de Salmonella spp. isoladas em uma planta de abate de aves.
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Data
2018-03-02
Autores
Dantas, Stéfani Thais Alves
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Universidade Estadual Paulista (Unesp)
Resumo
Salmonella spp. é uma bactéria entérica, responsável por graves doenças de origem alimentar e um dos principais agentes envolvidos em surtos no mundo todo. A contaminação ocorre, principalmente pelo consumo de carne de frango e ovos, uma vez que esses animais podem ser portadores de vários sorovares patogênicos para o homem. O objetivo do estudo foi avaliar o potencial patogênico de 40 cepas de Salmonella spp., isoladas de esteiras de um abatedouro de aves, por testes fenotípicos de adesão, invasão e produção de biofilme e análise genotípica da presença de vários genes relacionados com fatores de virulência, além de verificar sua persistência no ambiente e sua susceptibilidade a antimicrobianos por disco-difusão. Foi observada resistência à tetraciclina (17,5%) ampicilina (10%), cefotaxima (7,5%), cotrimoxazol (5%) e cloranfenicol (2,5%). Todas as cepas apresentaram os genes invA, sipB, sipD, ssaR, sifA, sitC, iroN, tolC, flgK, fljB e flgL. Os genes sopB e sipA estavam presentes em 92,5% dos isolados, enquanto sopD e spvB foram observados em 90% e 32,5% das cepas, respectivamente. Todos os isolados aderiram e invadiram células HeLa, com índice de invasão variando de 1,4 a 73,8%. Com relação à produção de biofilme, 31 (77,5%) cepas foram capazes de produzir biofilme em microplacas de poliestireno. Pela técnica de eletroforese em gel de campo pulsado (PFGE), detectou-se a persistência de clones no ambiente por até 18 semanas, entre as 20 amostradas. Não foi possível o estabelecimento de uma correlação entre as taxas de adesão e invasão e a presença/ausência dos genes codificadores de proteínas efetoras envolvidas nesses processos. Além disso, a capacidade dessas cepas em produzir biofilme e com isso, persistirem no ambiente e se dispersarem pelas superfícies de contato na planta de processamento, favorece a contaminação de alimentos de boa qualidade, fato agravado pelo potencial patogênico desses isolados demonstrados pela capacidade de adesão e invasão e pela resistência a vários antimicrobianos.
Salmonella spp. is an enteric bacterium responsible for serious foodborne disease, being one of the main agents involved in outbreaks worldwide. Contamination occurs mainly by poultry and egg consumption once these animals carry some pathogenic serotypes for the human being. Our aim was to evaluate the pathogenic potential of 40 strains of Salmonella spp., isolated from poultry slaughterhouse mats, by adhesion and invasion phenotypic tests, and biofilm production, and genotypic analysis to identify genes related to virulence factors, besides we verified its environment persistence and its antimicrobial susceptibility by disc-diffusion. We observed resistance to tetracycline (17.5%), ampicillin (10%), cefotaxime (7.5%), cotrimoxazole (5%) and chloramphenicol (2.5%). All strains possessed invA, sipB, sipD, ssaR, sifA, sitC, iroN, tolC, flgK, fljB and flgL genes. The genes sopB and sipA was present in 92.5% of the isolates, while sopD and spvB were observed in 90% and 32.5% of the strains, respectively. All strains adhered and invaded HeLa cells, with invasion index varying from 1.4 to 73.8%. Regarding to biofilm production, 31 (77.5%) strains were able to produce biofilm on polystyrene microplates. The Pulsed-field gel electrophoresis technique (PFGE) detected the existence of clones in the environment for up to 18 weeks, among de 20 sampled. It was not possible to establish a correlation between adhesion and invasion rates and the presence/absence of effector protein coding genes involved in these processes. In addition, the ability of these strains to produce biofilm and thus persist in the environment and disperse through contact surfaces in the processing plant, favors the contamination of good quality food, a fact aggravated by the pathogenic potential of these isolates demonstrated by the adhesion capacity and invasion and resistance to various antimicrobials.
Salmonella spp. is an enteric bacterium responsible for serious foodborne disease, being one of the main agents involved in outbreaks worldwide. Contamination occurs mainly by poultry and egg consumption once these animals carry some pathogenic serotypes for the human being. Our aim was to evaluate the pathogenic potential of 40 strains of Salmonella spp., isolated from poultry slaughterhouse mats, by adhesion and invasion phenotypic tests, and biofilm production, and genotypic analysis to identify genes related to virulence factors, besides we verified its environment persistence and its antimicrobial susceptibility by disc-diffusion. We observed resistance to tetracycline (17.5%), ampicillin (10%), cefotaxime (7.5%), cotrimoxazole (5%) and chloramphenicol (2.5%). All strains possessed invA, sipB, sipD, ssaR, sifA, sitC, iroN, tolC, flgK, fljB and flgL genes. The genes sopB and sipA was present in 92.5% of the isolates, while sopD and spvB were observed in 90% and 32.5% of the strains, respectively. All strains adhered and invaded HeLa cells, with invasion index varying from 1.4 to 73.8%. Regarding to biofilm production, 31 (77.5%) strains were able to produce biofilm on polystyrene microplates. The Pulsed-field gel electrophoresis technique (PFGE) detected the existence of clones in the environment for up to 18 weeks, among de 20 sampled. It was not possible to establish a correlation between adhesion and invasion rates and the presence/absence of effector protein coding genes involved in these processes. In addition, the ability of these strains to produce biofilm and thus persist in the environment and disperse through contact surfaces in the processing plant, favors the contamination of good quality food, a fact aggravated by the pathogenic potential of these isolates demonstrated by the adhesion capacity and invasion and resistance to various antimicrobials.
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Palavras-chave
Biofilme, Genes de virulência, Invasão, PFGE, Susceptibilidade a antimicrobianos, Antimicrobial susceptibility, Biofilm, invasion, Virulence genes