Edwardsiella tarda infection in Korean catfish, Silurus asotus, in a Korean fish farm

Abstract

Mass mortality of Korean catfish, Silurus asotus, occurred in a culture farm situated in Jeollabukdo Province, Korea. The cumulative mortality rates reached up to 5% of the total fish in the farm per day. In clinical signs, the affected fish showed abdominal distension, vent protrusion, enteritis, liver congestion and abscess‐like lesions in enlarged spleen and kidney. Histopathologically, in the liver, hepatocytes lost fat and underwent atrophy or necrosis. The spleen showed necrotized splenocytes and a haemorrhagic pulp. In the kidney, glomerular destruction, degeneration of renal tubular epithelial cell and haemorrhage were observed. However, necrotic muscular lesions were not observed. A pure bacterial isolate was obtained from the liver, spleen and kidney lesions of affected fish. Experimental infection of normal catfish with the isolate resulted in the development of clinical signs similar to those seen on the farm. The isolates were identified as Edwardsiella tarda through biochemical tests (99.4%) and analysis of bacterial genes (16S rDNA) sequences (98%). The bacteria possessed two virulent genes: sodB and katB genes. These results suggest that E. tarda can act as a pathogen of farmed catfish. This is the first report showing that E. tarda caused mortality in cultured Korean catfish.

Edwardsiella tardainfection in cultured Ya-fish,Schizothorax prenanti, in China

“…However, systemic abscesses and granulomatous inflammation, which were common signs in Korean catfish and red tilapia (Yu et al . ; Iregui et al . ), were not observed in this study.…”

“…Edwardsiella tarda is the causative agent of Edwardsiellosis , a common epizootic disease of cultured and wild aquatic animals such as channel catfish (Meyer & Bullock ), sea bass (Blanch, Pinto & Jofre ), Japanese flounder (Miwa & Mano ), turbot (Nougayrede, Vuillaume, Vigneulle, Faivre, Luengo & Delprat ; Lan, Zhang, Wang, Chen & Han ), brook trout (Uhland, Pierre & Robert ), European eels (Alcaide, Herraiz & Esteve ), red tilapia (Iregui, Guarín, Tibata & Ferguson ), pacu (Lima, Fernandes, Costa, Velasco, Leite & Hackett ), Indian major carp (Swain & Nayak ), Korean catfish (Yu, Han, Park, Park & Park ), Weddell seals (Park, Aoki & Jung ) and sperm whale (Cools, Haelters, Santiago, Claeys, Boelens, Leroux, Vaneechoutte & Deschaght ). Moreover, E. tarda is recognized as a serious human pathogen that may cause gastrointestinal and extraintestinal infections (Janda & Abbott ).…”

Edwardsiellosis in farmed turbot, Scophthalmus maximus (L.), associated with an unusual variant of Edwardsiella tarda: a clinical, aetiological and histopathological study

“…Challenge tests using E. tarda confirmed Koch's postulates, indicating that E. tarda was the causative agent of the disease. Edwardsiellosis, associated with E. tarda, has been reported in several species of fish, including mullets, Mugilidae G. Cuvier (Kusuda et al 1976), chinook salmon, Oncorhynchus tshawytscha (Walbaum) (Amandi et al 1982), flounder (Paralichthys olivaceus) (Nakatsugawa 1983;Miyazaki & Kaige 1985), red seabream, Pagrus major (Miyazaki & Kaige 1985), largemouth bass, Micropterus salmoides (Lacépède) (Francis-Floyd et al 1993), rainbow trout Oncorhynchus mykiss (Walbaum) (Reddacliff, Hornitzky & Whittington 1996), eel (Anguilla japonica) (Miyazaki & Kaige 1985), tilapias (Tilapia nilotica) (Miyazaki & Kaige 1985;Clavijo et al 2002) and catfish (Silurus asotus) (Yu et al 2009). Nougayrede et al (1994) first reported E. tarda infection in turbot.…”

First isolation and characterization ofEdwardsiella tardafrom diseased Asian swamp eel,Monopterus albus(Zuiew)

“…Edwardsiella tarda, a Gram-negative bacterium within the family Enterobacteriaceae, is the causative agent of edwardsiellosis (Shetty, Maiti, Venugopal & Karunasagar 2014). It has caused significant losses in many cultured freshwater and marine fish species throughout the world (Matsuoka & Nakai 2004;Castro, Toranzo, Barja, N uñez & Magariños 2006;Yu, Han, Kwon, Kwan & Sung 2009). In China, edwardsiellosis caused by E. tarda has been reported in many fish species, such as Japanese eel, Anguilla japonica (L.) (Chen, Wu & Gao 1998), turbot, Psetta maxima (L.) (Lan, Zhang, Wang, Chen & Han 2008) and Japanese flounder, Paralichthys olivaceus (L.) (Zhu, Shi, Zhang, Jiang, Xing, Zhao, Li & Wu 2006).…”