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Year 2017 - Volume 37, Number 4
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Minimum inhibitory concentration of Brazilian Brachyspira hyodysenteriae strains, 37(4):331-338
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ABSTRACT.- Daniel A.G.S., Sato J.P.H., Gabardo M.P., Resende T.P., Barcellos D.E.S.N., Pereira C.E.R. Vannucci F.A. & Guedes R.M.C. 2017. Minimum inhibitory concentration of Brazilian Brachyspira hyodysenteriae strains. Pesquisa Veterinária Brasileira 37(4):331-338. Departamento de Clínica e Cirurgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Avenida Pres. Antônio Carlos 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil. E-mail: guedesufmg@gmail.com
The objectives of this study were to characterize Brachyspira hyodysenteriae isolates and to evaluate the antimicrobial susceptibility patterns of strains obtained from pigs in Brazil based on the minimal inhibitory concentration test (MIC). The MIC was performed for 22 B. hyodysenteriae isolates obtained from 2011 to 2013 using the following antimicrobial drugs: tylosin, tiamulin, valnemulin, doxycycline, lincomycin and tylvalosin. Outbreaks of swine dysentery were diagnosed based on clinical presentation, bacterial isolation, gross and microscopic lesions, duplex PCR for B. hyodysenteriae and B. pilosicoli and nox gene sequencing. All obtained MIC values were consistently higher or equal to the microbiological cut-off described in the literature. The MIC 90 values for the tested drugs were 8µg/ml for doxycycline, >4µg/ml for valnemulin, 8µg/ml for tiamulin, 32µg/ml for tylvalosin, >64µg/ml for lincomycin and >128µg/ml for tylosin. These results largely corroborate those reported in the literature. Tiamulin, doxycycline and tylvalosin showed the lowest MIC results. All of the samples subjected to phylogenetic analysis based on the nox gene sequence exhibited similar results, showing 100% identity to B. hyodysenteriae. This is the first study describing the MIC pattern of B. hyodysenteriae isolated in Brazil. |
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