Identification of Tenacibaculum maritimum strains from marine farmed fish in Greece

Tenacibaculum maritimum (formerly Cytophaga marina and Flexibacter marinus) is an opportunistic bacterial pathogen that causes a disease called ‘flexibacteriosis’ in marine fish. Other names that have been used for flexibacteriosis are ‘gliding bacterial disease’, ‘eroded mouth syndrome’ and ‘black patch necrosis’. The disease is mainly characterised by haemorrhagic skin lesions and this condition is also associated with fin and gill disease. In a few cases, systemic forms have also been reported. Initially, T maritimum was isolated from marine fish cultured in Japan in 1979 (Hikida and others 1979). The first report in Europe was published in 1982, in Dover sole (Solea solea) (Campbell and Buswell 1982). Flexibacteriosis is currently widely spread in Europe, the USA and Japan, affecting many marine fish species (Vatsos 2007)

Based on phenotypic and biochemical characteristics, T maritimum is generally considered as a homogeneous taxon. Methods for isolation and identification of the pathogen include the following: observation of accumulations of long rods in wet mounts or gram-stained preparations obtained from gills or skin lesions; isolation in various culture media, especially Anacker and Ordal, Marine Agar, Flexibacter maritimus medium (FMM; Pazos and others 1996); and PCR (Toyama and others 1996, Avendaño-Herrera and others 2004).

Greece is the main producer of sea bream (Sparus aurata) and sea bass (Dicentrachus labrax) in the Mediterranean area. Flexibacteriosis is considered as one of the main bacterial diseases in these two …