Isolation,identification and antimicrobial susceptibility test of Edward-siella tarda in Bahaba taipingensis
Since the summer of 2023,there have been cases of outbreak and death in the Bahaba taipingensis Natural Conserva-tion Area in Dongguan City.The symptoms mainly include loss of appetite,reddening and congestion of body surface,protrud-ing eyeballs,opaque and ulcerated corneas,as well as ulceration in snout.Dissection revealed a large amount of ascites in ab-dominal cavity and enlarged liver with brown color.To determine the cause of the disease,and make prevention and control measures,we collected tissue samples such as heart,liver,spleen,kidney,intestine and gills from the dead fish.A dominant strain was isolated from and named as DG230920.Through a comprehensive analysis of its morphological characteristics,physiologi-cal and biochemical properties,in addition to the 16S rRNA gene sequence analysis,the bacteria were identified as Edwardsiella tarda.Pathological histological examination results show obvious inflammatory reactions in heart,liver,spleen,kidney and gills.Hemorrhage and desquamation of epithelial cells were observed in intestine;sparse lymphocytes and necrosis of endothelial cells were found in the spleen;tubular degeneration and necrosis were observed in the kidney.Gills showed shedding and hemor-rhage of gill filaments.Drug sensitivity analysis of the isolated strain revealed high sensitivity to ciprofloxacin and levofloxacin,with a minimum inhibitory concentration of only ≤0.25 mg·mL-1.The next most effective drug was imipenem,with a mini-mum inhibitory concentration of ≤0.5 mg·mL-1.The results indicate that the cause of B.taipingensis disease might be an infec-tion with E.tarda,and the isolated strain exhibited stable genetic sequences and sensitivity to clinically used antibiotics.The study suggests that prevention and control measures should be strengthened against E.tarda infection in B.taipingensis,and sensitive drugs should be used for treatment.
Bahaba taipingensisEdwardsiella tardaIsolation and identification of bacteriaPathological tissue sectionsDrug sensitivity test
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NSTL
万方数据
维普
