Isolamento e caracterização molecular de campylobacter termotolerantes de origem avícola
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2018-03-07
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Universidade Federal de Goiás
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Campylobacter thermotolerant species are frequently reported as one of the most important causes of human gastroenteritis, mainly caused by the consumption of contaminated poultry products. The knowledge of the pathogen prevalence in these products and the genetic correlation between the isolates are of extreme epidemiological importance. Therefore, it was proposed to evaluate the prevalence of thermoresistant species using a molecular method for the identification of Campylobacter jejuni, Campylobacter coli and Campylobacter lari and the use of molecular markers of genotyping in order to understand the genetic diversity of pathogenic species. For this, 300 carcases of refrigerated chickens collected in seven cold stores submitted to the Federal Inspection Service (SIF) were evaluated. The bacterial isolation technique was used first, and it was possible to determine the prevalence of Campylobacter in 34 carcases, totaling 11.3% of the total samples. It was verified that of the seven industries, two (A and C representing 28.5%) presented Campylobacter, of which only one (industry A) was verified the presence of the pathogen in more than one collection and in different seasons of the year. It was possible to obtain 48 Campylobacter isolates, which were submitted to real-time PCR analysis for genus confirmation and species determination. In addition, it was necessary to perform the conventional PCR analysis to determine the species in some isolates. After the molecular techniques were performed, 34 isolates (70.8%) belonged to the species Campylobacter jejuni; 08 isolates (16.6%) identified as Campylobacter coli and 06 isolates (12.5%) identified as Campylobacter lari. After identification of the species, the isolates were genotyped based on the analysis of restriction fragment polymorphisms of the flaA gene by the RFLP-flaA technique and were also evaluated by the small variable region sequencing technique of the flaA gene (SVR -FlaA). It was observed in this work that some isolates studied have high genomic similarity, which corroborates the hypothesis that the isolates of different companies have a source of contamination in common. In addition, the genetic similarity between thermotolerant species of the pathogen provides support for understanding the difficulty of determining the epidemiology of campylobacteriosis. The different genotypes and different restriction profiles found showed that in the same slaughterhouse there may be different sources of contamination of the carcasses. The number of isolates found here explains what is happening on the rest of the planet; the bacterium is present in poultry plants and should be monitored. In addition, the present study showed that SVR-flaA region sequencing and RFLP-flaA analysis were efficient and suitable methods for the subtyping of Campylobacter strains, it is worth mentioning that this is the first work involving the molecular subtyping of Campylobacter jejuni, Campylobacter coli and Campylobacter lari in the central-western region of Brazil.
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FEISTEL, J. C. Isolamento e caracterização molecular de campylobacter termotolerantes de origem avícola. 2018. 88 f. Tese (Doutorado em Ciência Animal) - Universidade Federal de Goiás, Goiânia, 2018.