斑点叉尾鮰源普通变形杆菌的分离、鉴定及药敏特性

【目的】对患病斑点叉尾鮰进行病原菌分离、鉴定及药敏实验,为斑点叉尾鮰肠道坏死病的防控提供参考。【方法】从患病斑点叉尾鮰病灶、肝、脾和肾分离纯化病原菌,经理化特性测定及16S rRNA基因序列分析对其进行鉴定,开展人工感染试验,并利用纸片扩散法进行药敏特性分析。【结果】分离菌株k1为本次引发斑点叉尾鮰病害的致病菌,其对斑点叉尾鮰的LD50为2.82×10~5 CFU/g。菌株k1理化特性与普通变形杆菌Proteus vulgaris基本一致,16S rRNA基因序列与普通变形杆菌相似性最高,综合判定分离菌株为普通变形杆菌。分离菌株k1对环丙沙星、头孢唑林及头孢拉定等12种抗生素高度敏感,对苯唑西林、阿莫西林及痢特灵等7种抗生素耐药。【结论】分离菌株k1是斑点叉尾鮰病原菌,养殖时可选用庆大霉素及氟苯尼考等药物进行防控。

Isolation, identification and antimicrobial susceptibility of Proteus vulgaris isolated from Ictalurus punctatus

Objective] We isolated, identified and tested antibiotic sensitivity of a pathogen from naturally infected Ictalurus punctatus. Methods] The pathogenic bacteria were isolated and purified from lesions, liver, kidney and spleen of Ictalurus punctatus. Strain k1 was identifies using the biochemical identification and 16S rRNA gene sequence determination. The artificial infection test was done, and antimicrobial susceptibility was tested by disc diffusion method. Results] Strain k1 was the pathogen of Ictalurus punctatus, and the LD50 of the isolates was 2.82×105 CFU/g. According to morphological and biochemical characteristics as well as the result of 16S rRNA gene sequence analysis, strain k1 was identified as Proteus vulgaris. Strain k1 was susceptible to 12 agents including ciprofloxacin, cefazolin, cefadroxil and other antibiotics. Meanwhile, it showed resistance to oxacillin, amoxicillin, furazolidone and other 7 antibiotics. Conclusion] our results demonstrated that Proteus vulgaris was the pathogen causing high mortality in Ictalurus punctatus, and the disease may prevent by using drugs such as gentamicin and neomycin in fisheries.