Diagnosis of Micrococcus luteus Infection in Cultured Sharpsnout Sea Bream(Diplodus puntazzo Cetti, 1777)

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The aim of this study was to determinate the causative agent of mortalities in sharpsnout sea bream (Diplodus puntazzo Cetti, 1777) cultured in the Aegean Sea. Ten individuals (200-350 g) in were investigated total between May 2009 – 2010 using bacteriological methods. Moribund fish samples exhibited pale gills and liver, skin depigmentation, hemorrhages on the liver and muscles. Bacteriological samples of liver, kidney and spleen were streaked onto Marine Agar (MA) and Tryptic Soy Agar (TSA) plates containing 1,5% NaCl and incubated at 22°C for 48h. Gram-positive non-motile cocci were isolated from visceral organs of diseased fish samples. According to their morphological and biochemical characteristics, these isolates were identified as Micrococcus luteus. Kirby-Bauer disk diffusion method was also performed using multidisc. Results were interpreted based on the available data and all isolates were determined to be sensitive against oxytetracycline, erythromycin and chloramphenicol. Histopathologically, vacuolar degeneration and necrosis in the parenchyma cells of liver, tubular necrosis in the kidney and hemosiderin deposite in the spleen were determined. In addition to melting lamella, epithelial cells hyperplasia in the gills was observed. In conclusion, in this study an epizootic with a low mortality rate caused by M. luteus was described and this study is the first report of the pathogen in the cultured sharpsnout sea bream.

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Sharpsnout Sea Bream , Cage Culture , Micrococcus luteus

Erciyes University Journal Of The Institute Of Science an‎d Technology

220

Erciyes University Journal Of The Institute Of Science an‎d Technology