Detecção de genes de virulência de Staphylococcus aureus identificados por PCR em amostras de leite de vacas com mastite clínica ou subclínica
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2014-02-21
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Universidade Federal de Goiás
Resumo
Staphylococcus aureus can produce a wide variety of virulence factors secreted or
associated with bacterial wall, among them the exotoxins. The pathogenicity of S.
aureus to the bovine udder is not quite clarified, but the staphylococcal exotoxins
and their combinations may play a role in the pathogenic potential of the
microorganism. Considering that knowing the virulence factors of S. aureus
provides an important information of the establishment of effective control
strategies of intramammary infections we aimed to detect the DNA of S. aureus
isolates from milk of cows with clinical or subclinical mastitis and identify genes
encoding bacterial exotoxins and superantigens. For this purpose, in the present
study were used 55 isolates of S. aureus, obtained from milk samples from cows
with clinical or subclinical mastitis. The isolates were electronically identified using
the methodology described by Vitek 2® device manual. Genomic DNA extrac ted
using the High Pure PCR Template Preparation Kit. The laboratory analysis for
detection of species and genes encoding the exotoxins were performed at the
Laboratório de Especialidades Biológicas of Centro de Pesquisa em Alimentos of
Escola de Veterinária e Zootecnia da Universidade Federal de Goiás
(LEB/CPA/EVZ/UFG). The gene eta was detected in 85,5% of the isolates, the pvl
gene in 63,6% and the tst gene in 14,5%. The etb gene was not isolated. It was
verified that the Real Time PCR technique for detection of sodA gene proved to be
effective in identifying the species S. aureus, and may become an important tool in
the diagnosis of the bovine mastits causing microorganisms. The isolates of S.
aureus mastitis harbor genes exotoxins, such as pvl, tst and eta, which the last
one may play an important role in the pathogenesis of bovine mastitis since the
majority of the isolates showed to be positive for its presence.
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FREITAS, Fernanda Antunha de. Detecção de genes de virulência de Staphylococcus aureus identificados por PCR em amostras de leite de vacas com mastite clínica ou subclínica. 2014. 65 f. Dissertação (Mestrado em Ciência Animal) - Universidade Federal de Goiás, Goiânia, 2014.