Aeromonas sobria, an outbreak of natural infection in cultured silver catfish Rhamdia quelen (Quoy & Gaimard, 1824) in Argentina.

COSCELLI, G.; CASABONE, C.; MORÓN-ALCAIN, E.; ARANCEGUI, N.; VIGLIANO, F.A.

JOURNAL OF FISH DISEASES

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017

0140-7775

In this work, the disease outbreak in farmed silver catfish (Rhamdia quelen) naturally infected with Aeromonas sobria was reported. Gross, microscopic and bacteriological findings in affected specimens were described. Diseased fish displayed extensive petechial and ecchymotic haemorrhages in the skin, fins, mouth and oral cavity, skin congestion and necrosis of fins. Microscopically, the most significant lesions consisted in haemorrhages in dermis, epidermal erosion and epidermitis, severe necrosis of fins, generalized congestion and mild haemorrhages in kidney and liver. A. sobria was isolated, identified and characterized by traditional biochemical tests and by the API 20NE from samples of skin, spleen and kidney of diseased fish. In addition, a PCR technique to identify the presence of hemolysin gene of A. sobria (asa1 gene) from the pure culture of bacterial isolates was applied. The pathologic changes, consistent with haemorrhagic septicaemia, and the isolation of A. sobria from internal organs, indicate that the bacterium was involved in the disease outbreak in silver catfish, causing a systemic infection in susceptible specimens.