黄沙鳖致病性蜡样芽孢杆菌的分离鉴定及药敏试验

Isolation,Identification and Antibiotic Sensitivity Test of Pathogenic Bacillus cereus from Huangsha Turtle

【目的】对广西武宣县某养殖场患病黄沙鳖(Pelodiscus sinensis)进行病原菌分离鉴定及药敏试验,为防治黄沙鳖蜡样芽孢杆菌病提供参考依据。【方法】采用常规方法对患病黄沙鳖进行细菌分离,通过人工感染试验确定其致病性。采用API 50CH生化鉴定和16S rRNA序列分析进行细菌鉴定,并以K-B纸片扩散法及二倍稀释法进行药敏试验。【结果】从患病黄沙鳖肝脏中分离获得1株具有芽孢的革兰氏阳性杆菌GXWXAA,对健康黄沙鳖致死率达100.0%。经鉴定,菌株GXWXAA属于蜡样芽孢杆菌(Bacillus cereus),与蜡样芽孢杆菌JY5(HQ833024)、JY7(HQ833025)、JY9(HQ833026)和VBE16(MG027671)的亲缘关系最近,相似性均达99.9%。菌株GXWXAA对新霉素、恩诺沙星和多西环素等15种抗生素敏感,对头孢曲松、环丙沙星和依诺沙星中介,对青霉素G、氨苄青霉素、复达欣、复方新诺明和多粘菌素B耐药。新霉素、恩诺沙星和多西环素对菌株GXWXAA的最小抑菌浓度分别为0.488、0.122和0.244μg/mL。【结论】引起广西武宣县某养殖场黄沙鳖发病的病原菌属于蜡样芽孢杆菌,建议选择新霉素、恩诺沙星和多西环素等抗生素对患病黄沙鳖进行治疗。

【Objective】Isolation,identification and antibiotic sensitivity test of the pathogenic bacteria were conducted in the diseased Huangsha turtle(Pelodiscus sinensis)from a farm of Wuxuan,Guangxi,in order to give some reference for the prevention and treatment of the disease caused by Bacillus cereus in Huangsha turtle.【Method】Pathogenic bacteria were isolated from diseased Huangsha turtle by routine methods.The pathogenicity was determined by artificial infection test.Bacterial identification was conducted by API 50 CH biochemical identification and 16S rRNA gene sequencing analysis.The antibiotic sensitivity was carried out by K-B disk diffusion method and double dilution method respectively.【Result】Strain GXWXAA which is a kind of gram-positive rod shaped bacteria with spores was isolated from the liver of diseased Huangsha turtle.This isolate contributed a mortality rate of 100.0%to healthy Huangsha turtle according to artificial infection experiment.GXWXAA was identified as B.cereus,and had the closest relationship relatives with B.cereus JY5(HQ833024),JY7(HQ833025),JY9(HQ833026)and VBE16(MG027671),sharing similarity of 99.9%.Antibiotic sensitivity test results showed that strain GXWXAA was highly sensitive to 15 kinds of antibiotics such as neomycin,enrofloxacin and doxycycline,moderately sensitive to ceftriaxone,ciprofloxacin and enoxacin,and insensitive to penicillin G,ampicillin,fortum,sulfamethoxazole and polymyxin B.Minimum inhibitory concentration(MICs)of neomycin,enrofloxacin and doxycycline to strain GXWXAA were 0.488,0.122 and 0.244μg/mL,respectively.【Conclusion】B.cereus was the pathogen causing the disease of Huangsha turtle in the farm of Wuxuan,Guangxi.Antibiotics like neomycin,enrofloxacin and doxycycline were recommended for medication of diseased Huangsha turtle in this farm.