Studies on Epizootiology and Pathogenicity of Staphylococcus epidermidis in Tilapia (Oreochromis spp.) Cultured in Taiwan

Shih-Ling Huang, Wei-Cheng Chen, Mei-Chuan Shei, I-Chiu Liao and Shiu-Nan Chen (1999) Studies on epizootiology and pathogenicity of Staphylococcus epidermidis in Tilapia (Oreochromis spp.) cultured in Taiwan. Zoological Studies 38(2): 178-188. This paper describes the epizootiology of a disease of tilapia with clinical signs that include white nodules and microscopic granulomatous formations. Diseased fish showed splenomegaly with diffusion of numerous white nodules. The most severe lesions were presented in the spleen and anterior kidney. Morphological, biological, and biochemical characteristics of microorganisms isolated from the diseased tilapia were examined and classified by Baird-Parker’s biochemical subgrouping scheme. Strain LK0728 identified as Staphylococcus epidermidis, was used in a challenge test. Histopathological changes were similar to those seen in naturally infected fish. This is the 1st report on the isolation of staphylococci pathogenic to tilapia and on the confirms the etiological agent causing mass mortality in tilapia from 1992 to 1996 in Taiwan.