Assuntos
Aeromonas/classificação , Aeromonas/genética , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Percas , Aeromonas/efeitos dos fármacos , Aeromonas/enzimologia , Animais , Animais Selvagens , Antibacterianos/farmacologia , Pesqueiros , Infecções por Bactérias Gram-Negativas/microbiologia , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genéticaRESUMO
Arctic char Salvelinus alpinus farmed in different places in Austria and free of the viral diseases viral haemorrhagic septcaemia (VHS), infectious haematopoietic necrosis (IHN) and infectious pancreatic necrosis (IPN) experienced disease and mortality. Diseased fish showed skin ulceration and pathological signs of sepsis. Aeromonas sp. was isolated as pure culture from the kidney of freshly euthanized diseased fish. Three independent isolates from outbreaks that occurred on 2 of the affected farms were analyzed phylogenetically by DNA sequence analysis of the rrs and gyrB genes and phenotypically with biochemical reactions. All 3 isolates were identified as Aeromonas salmonicida subsp. smithia. Analysis of virulence genes in these isolates revealed the presence of a Type III secretion system as well as several related virulence effector genes including aexT, encoding the Aeromonas exotoxin AexT, aopP and aopH. These genes are characteristic for virulent strains of typical and atypical subspecies of A. salmonicida.
Assuntos
Aeromonas salmonicida/fisiologia , Surtos de Doenças , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Dermatopatias Bacterianas/veterinária , Truta/microbiologia , Aeromonas salmonicida/classificação , Aeromonas salmonicida/genética , Aeromonas salmonicida/patogenicidade , Animais , Áustria/epidemiologia , Doenças dos Peixes/patologia , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Dados de Sequência Molecular , Filogenia , Homologia de Sequência do Ácido Nucleico , Dermatopatias Bacterianas/epidemiologia , Dermatopatias Bacterianas/microbiologia , Dermatopatias Bacterianas/patologia , Especificidade da Espécie , Virulência/genéticaRESUMO
Motile aeromonad septicaemia caused by Aeromonas sobria is a cause of disease in farmed perch, Perca fluviatilis L., in Switzerland. We have evaluated the potential of a Pseudomonas chlororaphis isolate, obtained from perch intestine, to control A. sobria infection. Inoculation of juvenile perch with P. chlororaphis strain JF3835 prior to infection with A. sobria caused a reduction in A. sobria associated mortalities. Infection of perch with xylE-labelled P. chlororaphis indicated the bacterium is able to transiently colonize juvenile fish and fingerlings.
Assuntos
Aeromonas , Doenças dos Peixes/dietoterapia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Percas , Probióticos/uso terapêutico , Pseudomonas/fisiologia , Animais , Doenças dos Peixes/mortalidade , Infecções por Bactérias Gram-Negativas/dietoterapia , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/mortalidade , Testes de Sensibilidade Microbiana/veterinária , SuíçaRESUMO
Pathogenic Aeromonas sobria has been identified as a causative agent of ulcerative disease in farmed European perch, Perca fluviatilis L. To study the effect of the normal intestinal bacterial flora of perch against A. sobria, we sampled 193 bacterial isolates from the perch digestive tract. The isolates were identified by sequence analysis of the 16S rRNA gene and their inhibitory potential against A. sobria was evaluated in vitro. Nineteen of the strains isolated showed inhibition and were also tested against other aeromonad and non-aeromonad fish pathogens including Yersinia ruckeri and Vibrio anguillarum. Isolates showing inhibition were primarily Pseudomonas spp.; however, inhibitory Shewanella spp., and Delftia sp. were also identified. A Pseudomonas chlororaphis isolate showed inhibition against all fish pathogens tested.
Assuntos
Aeromonas/crescimento & desenvolvimento , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Percas/microbiologia , Animais , Aquicultura , Técnicas de Cocultura , DNA Bacteriano/química , DNA Bacteriano/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/prevenção & controle , Intestinos/microbiologia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genéticaRESUMO
Bacteriological and serological investigations were performed to assess whether the domestic sheep population is a reservoir of Mycoplasma conjunctivae in Switzerland. Among a sample of 69 sheep showing clinical signs of infectious keratoconjunctivitis (IKC) in three Swiss cantons, M. conjunctivae was identified 53 times (76.8%). A commercially prepared indirect ELISA was used to detect M. conjunctivae antibodies in 674 sera of adult sheep. We analysed a stratified random sample of 123 sheep herds from 25 out of the 26 Swiss cantons. At least one positive animal was detected in 89.4% of the herds. In positive herds (n=110), 57.1% of the individual animals tested positive. To assess the importance of sheep's age in the spread of M. conjunctivae, 209 sera of adult sheep and 93 lamb sera among eight sheep herds were analysed using the indirect ELISA. Seroprevalence in 2-6-month-old lambs was 50.5%, indicating that the IKC agent is spread in sheep flocks during raising. Lambs experimentally infected with M. conjunctivae carried the agent for 8 and 23 weeks, respectively, depending on the strain used for challenge. We conclude that the M. conjunctivae-infection is endemic and self-maintained in the domestic sheep population in Switzerland.