Identification and susceptibility test of pathogenic Aeromonas veronii isolated from Siniperca chuatsi

Abstract:

[Objective] To determine the cause of death for Siniperca chuatsi and screen sensitive drugs, a dominant bacteria WJ2014-1 was isolated from the liver of sick S. chuatsi. This study will provide reference for further prevention and treatment of Aeromomas veronii in S. chuatsi. [Methods] The pathogenic bacteria were isolated and purified from the liver of S. chuatsi. And the identification of phenotypic information of the strain WJ2014-1 was conducted, including the biochemical identification and 16S rRNA gene sequence determination. Antimicrobial susceptibility test was conducted by disk diffusion technique. [Results] The results of artificial infection tests by using WJ2014-1 to infect S. chuatsi displayed that the prevalence of symptoms and spontaneous onset symptoms were the same. According to morphological and biochemical characteristics as well as the result of 16S rRNA gene sequence analysis, the isolated strain WJ2014-1 was A. veronii. WJ2014-1 was susceptible to sulfamethoxazole, doxycycline, roxithromycin, cefotaxime, piperacillin and other 21 kinds of antibiotics. Meanwhile, it showed resistance to chloramphenicol, norfloxacin, nalidixic acid and other 9 kinds of antibiotics. [Conclusion] The isolated bacterial strain WJ2014-1 was pathogenic to S. chuatsi, and prevented by administering drugs such as sulfamethoxazole, doxycycline and roxithromycin in fisheries production.