Natural coinfection by Streptococcus agalactiae and Francisella noatunensis subsp. orientalis in farmed Nile tilapia (Oreochromis niloticus L.).
J Fish Dis
; 40(1): 51-63, 2017 Jan.
Article
em En
| MEDLINE
| ID: mdl-27144661
ABSTRACT
Streptococcus agalactiae and Francisella noatunensis subsp. orientalis (Fno) are important pathogens for farm-raised tilapia worldwide. There are no reports of coinfection caused by S. agalactiae and Fno in fish. This study aimed to determine the aetiology of atypical mortalities in a cage farm of Nile tilapia and to characterize the genetic diversity of the isolates. Fifty-two fish were sampled and subjected to parasitological and bacteriological examination. The S. agalactiae and Fno isolates were genotyped using MLST and REP-PCR, respectively. Whole-genome sequencing was performed to confirm the MLST results. Seven fish were shown coinfected by S. agalactiae and Fno. Chronic hypoxia and a reduction in the water temperature were determined as risk factors for coinfection. Fno isolates were shown clonally related in REP-PCR. The MLST analysis revealed that the S. agalactiae isolates from seven coinfected fish were negative for the glcK gene; however, these were determined to be members of clonal complex CC-552. This is the first description of coinfection by S. agalactiae and Fno in farm-raised Nile tilapia. The coinfection was predisposed by chronic hypoxia and was caused by the main genotypes of S. agalactiae and Fno reported in Brazil. Finally, a new S. agalactiae genotype with glcK gene partially deleted was described.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Infecções Estreptocócicas
/
Streptococcus agalactiae
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Variação Genética
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Infecções por Bactérias Gram-Negativas
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Ciclídeos
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Doenças dos Peixes
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Francisella
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Revista:
J Fish Dis
Assunto da revista:
BIOLOGIA
/
MEDICINA VETERINARIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Brasil