Experimental mycobacteriosis in striped bass Morone saxatilis

Diseases of Aquatic Organisms

W. K. Vogelbein¹  C. A. Ottinger¹  D. T. Gauthier¹  H. Kator¹  M. W. Rhodes¹ 

关键词: Mycobacteriosis;    Striped bass;    Morone saxatilis · Mycobacterium marinum · Mycobacterium gordonae · Mycobacterium shottsii;    Granuloma;   

DOI  :  10.3354/dao054105

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Striped bass Morone saxatilis were infected intraperitoneally with approximately 10⁵ Mycobacterium marinum, M. shottsii sp. nov., or M. gordonae. Infected fish were maintained in a flow-through freshwatersystem at 18 to 21°C, and were examined histologically and bacteriologically at 2, 4, 6, 8, 17, 26, 36 and 45 wk post-infection (p.i.). M. marinum caused acute peritonitis, followed by extensive granuloma development in the mesenteries, spleen andanterior kidney. Granulomas in these tissues underwent a temporal progression of distinct morphological stages, culminating in well-circumscribed lesions surrounded by normal or healing tissue. Mycobacteria were cultured in high numbers from splenictissue at all times p.i. Standard Ziehl-Neelsen staining, however, did not demonstrate acid-fast rods in most early inflammatory foci and granulomas. Large numbers of acid-fast rods were present in granulomas beginning at 8 wk p.i. Between 26 and 45 wkp.i., reactivation of disease was observed in some fish, with disintegration of granulomas, renewed inflammation, and elevated splenic bacterial densities approaching 10⁹ colony-forming units g^-1. Infection with M. shottsii orM. gordonae did not produce severe pathology. Mild peritonitis was followed by granuloma formation in the mesenteries, but, with 1 exception, granulomas were not observed in the spleen or anterior kidney. M. shottsii and M. gordonaeboth established persistent infections in the spleen, but were present at densities at least 2 orders of magnitude less than M. marinum at all time points observed. Granulomas in the mesenteries of M. shottsii- and M.gordonae-infected fish resolved over time, and no reactivation of disease was observed.

【 授权许可】

Unknown