Affiliation:
1. Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
2. Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China
3. College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, China
4. Fisheries College, Hunan Agricultural University, Changsha 410128, China
Abstract
Aeromonas veronii, an opportunistic pathogen toward aquatic organisms, was identified as the causative pathogen (isolate WH10) in diseased bronze gudgeon via bacterial isolation, and morphological, physiological, biochemical, and molecular characterization. WH10 exerted its pathogenicity via five virulence genes, including those encoding cytotoxic enterotoxins (act and alt), lipase (lip), a quorum sensing-controlled virulence factor (LuxS), and a Type III secretion system inner membrane component (ascV). WH10 was shown to be sensitive to compound sulfamethoxazoles, cefothiophene, doxycycline, and sulfamethoxazole. Toward bronze gudgeon, WH10 had a median lethal dose (LD50) of 1.36 × 106 colony forming units/mL. Analysis of blood parameters of diseased fish revealed significant increases in monocytes and neutrophils, but decreased numbers of lymphocytes. Serum aspartate aminotransferase activity and triglyceride concentration were significantly higher in diseased fish than in healthy fish. The reverse was noted for alkaline phosphatase, total protein, albumin, total cholesterol, and glucose. Thus, Aeromonas veronii is implicated as the causative agent of the mass mortality observed in bronze gudgeon, warranting further investigations into the diagnosis, epidemiology, prevention, and treatment of this infectious disease.
Funder
Central Public-interest Scientific Institution Basal Research Fund, CAFS
National Freshwater Aquatic Germplasm Resource Center