Large‐scale mortality in cultured tilapia Oreochromis niloticus due to infection with Shewanella putrefaciens in India
Large‐scale mortality in cultured tilapia Oreochromis niloticus due to infection with Shewanella putrefaciens in India
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DOI：
10.1111/jwas.12686
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发表时间：
2020-02
影响因子：
2.8
通讯作者：
N. Sood;P. K. Pradhan;Ravindra;D. K. Verma;M. Yadav;R. Mishra;U. Kumar;T. Swaminathan;N. Sood
中科院分区：
文献类型：
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作者：
N. Sood;P. K. Pradhan;Ravindra;D. K. Verma;M. Yadav;R. Mishra;U. Kumar;T. Swaminathan;N. Sood
近年来，腐败希瓦氏菌感染已成为淡水养殖中的一个严重问题。在本研究中，我们报告了来自印度北部希萨尔的养殖罗非鱼Oreochromis niloticus的大规模死亡率。患病罗非鱼表现为嗜睡、近水面游泳、烂鳍、鳃盖萎缩，死亡率约40%。从患病罗非鱼的肾脏中分离出革兰氏阴性、能动、过氧化氢酶和氧化酶阳性杆菌，并确认为S。根据生化试验和16 S rRNA基因测序结果，对腐败菌进行鉴定。药敏试验结果表明，S。腐败菌对喹诺酮类、硝基呋喃类、四环素类、氨基糖苷类、头孢菌素类、氨基环醇类、磺胺类和大环内酯类抗生素敏感，但对β-内酰胺类和糖肽类抗生素耐药。组织病理学检查显示肾脏、肝脏、脾脏和肠道发生退行性变化，提示全身感染。在实验性感染研究中，该疾病在幼稚罗非鱼中重现，临床症状与自然病例中观察到的相似。此外，S。从受攻击的罗非鱼的肾脏中重新分离出腐败杆菌，满足科赫假设。因此，罗非鱼的死亡归因于S。腐败菌感染
In recent years, infection with Shewanella putrefaciens has emerged as a serious problem in freshwater aquaculture. In the present study, we report large‐scale mortality in farmed tilapia Oreochromis niloticus from Hisar, North India. The diseased tilapia exhibited lethargy, swimming near the water surface, fin rot, hemorrhages on the operculum, and approximately 40% mortality. Gram‐negative, motile, catalase, and oxidase‐positive bacilli were isolated from the kidney of affected tilapia and confirmed as S. putrefaciens on the basis of biochemical tests and 16S rRNA gene sequencing. The antimicrobial sensitivity test revealed that S. putrefaciens strains were sensitive to quinolone, nitrofuran, tetracycline, aminoglycoside, cephalosporin, aminocyclitol, sulphonamide, and macrolide antibiotics, but resistant to beta‐lactam and glycopeptide antibiotics. The histopathological examination revealed degenerative changes in the kidney, liver, spleen, and intestine suggesting systemic infection. In experimental infection studies, the disease was reproduced in naive tilapia, and the clinical signs resembled those observed in natural cases. Further more, S. putrefaciens was re‐isolated from the kidney of challenged tilapia, fulfilling Koch's postulates. Therefore, the mortality in tilapia was attributed to S. putrefaciens infection.