Identification and Biological Characteristics tarda Isolated from Pelteobagrus fulvidraco

Over the past five years,an epidemic disease broke out in Pelteobagrus fulvidraco ponds of Zhejiang Province. The diseased fish mainly exhibits head splitting and surface bleeding; dissection results reveal hepatonephromegaly and abdominal bleeding. A bacterial strain HSY201301 was isolated from the liver tissue of P. fulvidraco with typical symptoms. Artificial infection experiment confirmed that the isolated strain had a strong virulence to healthy P. fulvidraco,leading to similar symptoms to naturally infected P. fulvidraco. The isolated strain was identified as an Edwardsiella tarda strain according to conventional morphological,physiological,biochemical characteristics and 16 S rRNA gene sequence. Results of drug susceptibility test indicated that the isolated strain was sensitive to ciprofloxacin,doxitard,penicillin,doxycycline,and rocephin. This study laid solid foundation for effective prevention and control of E. tarda.