Weissella sp. outbreaks in commercial rainbow trout (Oncorhynchus mykiss) farms in Brazil.
Vet Microbiol
; 156(3-4): 359-66, 2012 May 04.
Article
em En
| MEDLINE
| ID: mdl-22137197
The genus Weissella contains 14 bacterial species that usually occur in nutrient-rich environments and in fermented foods and beverages. Outbreaks of hemorrhagic septicemia were reported in three commercial rainbow trout (Oncorhynchus mykiss) farms in Brazil in 2008 and 2009. Seventy-seven Gram-positive isolates were obtained from 41 diseased fish from these farms. The bacterial strains were identified as Weissella at the genus level using biochemical tests, Weissella genus-specific PCR, and 16S rRNA sequencing. To evaluate potential routes of infection, rainbow trout juveniles were experimentally infected with the pathogen. In addition, the resistance of the pathogen to five antibiotics was tested, and provisional epidemiological cut-off values were calculated using the normalized resistance interpretation (NRI). All isolates presented similar phenotypic profiles and positive reactions for Weissella genus-specific PCR. The 16S rRNA sequences of the Brazilian strains showed 100% similarity with sequences of Chinese isolates that previously were identified as the first case of Weissella sp. infection in fish. The disease was successfully reproduced in the laboratory by intraperitoneal injection, immersion, and cohabitation between diseased and healthy fish. All isolates were resistant to sulfonamide, and based on NRI analysis, one, two, and three isolates were classified as non-wild-type (NWT) for erythromycin, oxytetracycline, and norfloxacin, respectively. This is the first description of multiple cases of Weissella sp. infection in rainbow trout farms outside of China, of infectious routes for the disease, and of provisional epidemiological cut-off values for resistance of these bacteria to four antibiotics.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Infecções por Bactérias Gram-Positivas
/
Septicemia Hemorrágica
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Oncorhynchus mykiss
/
Weissella
/
Doenças dos Peixes
Limite:
Animals
País/Região como assunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Vet Microbiol
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Holanda