Outbreaks and genetic diversity of Francisella noatunensis subsp orientalis isolated from farm-raised Nile tilapia (Oreochromis niloticus) in Brazil.
Genet Mol Res
; 13(3): 5704-12, 2014 Jul 25.
Article
em En
| MEDLINE
| ID: mdl-25117328
Francisella noatunensis subsp orientalis (FNO) is an emerging pathogen of warm water tilapia in a number of different countries. The disease caused by this bacterium in fish is characterized by a systemic granulomatous infection that causes high mortality rates during outbreaks. FNO has been previously described in Asia, Europe, and Central and North America. Its occurrence in South America has never been described. Since 2012, outbreaks of a granulomatous disease have been recorded in cage farms of Nile tilapia (Oreochromis niloticus L.) in Brazil. The current study aimed to identify the etiologic agent of recent francisellosis outbreaks at Brazilian tilapia farms, and to characterize the genetic diversity of the pathogen from farms with distinct geographic origins and without epidemiological connections. Bacteriological analysis of 44 diseased Nile tilapia collected from five cage farms in Brazil was performed during 2012 and 2013. The farms were in different locations and had no recent history of animal or biological material transport between each other. Sixty-two FNO isolates were identified on the basis of FNO-specific qPCR. The main predisposing factors for the occurrence of outbreaks on Brazilian farms were lower water temperature (<22°C) and life stage of fish, affecting mainly fry, fingerlings and young adults (live weight <100 g). The genetic diversity of the Brazilian FNO isolates was evaluated using repetitive extragenic palindromic-PCR. The isolates from different origins were shown to be clonally related. This is the first report of the occurrence and genetic diversity of FNO in South America.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Variação Genética
/
Surtos de Doenças
/
Infecções por Bactérias Gram-Negativas
/
Ciclídeos
/
Doenças dos Peixes
/
Francisella
Tipo de estudo:
Prognostic_studies
Limite:
Animals
País/Região como assunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Genet Mol Res
Assunto da revista:
BIOLOGIA MOLECULAR
/
GENETICA
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Brasil