摘要

细菌感染性疾病是水产养殖业中的一个主要危险问题。它在鱼类和人类中引起多种疾病，并具有相当大的毒力潜力。在这方面，研究焦点的重点是区分从天然的Labeo rohita鱼中回收的细菌分离株及其毒性特征。基于β-溶血因子，选择四种分离物（KADR11，KADR12，KADR13和KADR14）进一步描绘。这些细菌分离株与Providencia rettgeri，气单胞菌（Aeromonas sp。），气单胞菌（Aeromonas sp。），和气单胞菌（Aeromonas entero），分别使用部分16S r-RNA基因扩增和生化特征分析。进一步的研究表明，在SDS_PAGE分析中，分离株的毒力特征表明分离的外膜蛋白（OMP）和脂多糖（LPS）分别出现在19_80kDa和20_100kDa之间。所有四种菌株对β-内酰胺类抗生素都完全耐药（100％）。罗氏沼虾分别腹腔注射普罗威登斯菌KADR11，气单胞菌（Aeromonas sp。）的2.0×10⁴，2.0×10⁵，2.0×10⁶，2.0×10⁷和2.0×10⁸个细胞/ KADR12，气单胞菌属。 KADR13和气单胞菌KADR14用于测定致死剂量50（LD50）值，分别为2.4×10⁷,4.1×10⁵,2.7×10⁷和7.4×10⁵个细胞/鱼。结果表明，分离的菌株对L. rohita具有较高的致病潜力。

Bacterial infectious diseases are a main dangerous problem in Aquaculture farming. It causes multiple diseases in fish as well as in human being and it has considerable virulence potential. In this connection, the moot of study focus to discriminate bacterial isolates recovered from naturally diseased Labeo rohita fish and their virulent characteristics. Based on the β–haemolysis factor, four isolates (KADR11, KADR12, KADR13 and KADR14) were selected for further delineation. These bacterial isolates showed high similarity with Providencia rettgeri, Aeromonas sp., Aeromonas sp. and Aeromonas enteropelogenes respectively, using partial 16S r-RNA gene amplification and biochemical characterizations were also supported. The further study investigates the virulence characteristics of isolates showed separation of outer membrane proteins (OMPs) and lipopolysaccharides (LPS) which appeared between 19_80 kDa and 20_100 kDa in SDS_PAGE analysis respectively. All the four strains were complete resistant (100%) to β-lactam antibiotics. L. rohita were injected intraperitoneally with 0 (control), 2.0 × 10⁴, 2.0 × 10⁵, 2.0 × 10⁶, 2.0 × 10⁷ and 2.0 × 10⁸ cells/fish of Providencia rettgeri KADR11, Aeromonas sp. KADR12, Aeromonas sp. KADR13 and Aeromonas enteropelogenes KADR14 for the determination of lethal dose 50 (LD50) values, which were 2.4 × 10⁷, 4.1 × 10⁵, 2.7 × 10⁷ and 7.4 × 10⁵ cells/fish respectively. The results indicated that isolated strains were possessed the high pathogenic potential for L. rohita.

https://www.sciencedirect.com/science/article/pii/S0882401017300165