海豚致病性嗜水气单胞菌的分离鉴定及药敏试验

Isolation and Identification of Pathogenic Aeromonas Hydrophila from Dolphins and Drug Sensitivity Test

为探究昆明某海洋馆患病海豚死亡原因,将死亡海豚进行剖检,发现其肝脏、肾脏肿大,肾包膜积液,肺脏出血并伴有纤维素性渗出,胃肠道点状出血;无菌采集死亡海豚肝脏、肺脏、肾脏积液分离培养,得到3株优势菌株,通过菌落形态特征观察、革兰染色镜检、PCR扩增、序列比对、构建系统发育树、生化试验检测,确定优势菌株均为嗜水气单胞菌(Aeromonas hydrophila)。用分离到的菌株进行动物回归试验,结果显示,接种菌液后的SPF昆明系小鼠出现精神沉郁、腹围增大等症状,接种后4 h开始死亡,16 h后全部死亡;剖检发现小鼠肺脏、肠道出血、肝肾出血肿大。无菌环境下取小鼠肺脏、肝脏、肾脏等病变部位进行复检,结果显示,从肝脏、肾脏、肺脏中回收到的菌株菌落形态、镜检结果、生化鉴定结果、DNA序列与目的菌相同。药敏试验结果显示,该菌对氟苯尼考、恩诺沙星、诺氟沙星、庆大霉素和卡那霉素极度敏感;氨苄西林、红霉素高度敏感;磺胺嘧啶和四环素耐药。本次试验为昆明海洋馆其余同群海豚的防治提供了科学依据。

In order to explore the death cause of diseased dolphins in a marine museum in Kunming,the dead dolphins were dissected and found to have hemorrhage in the livers and kidneys.Renal capsule effusion,and pulmonary hemorrhage accompanied by fibrinous exudation and gastrointestinal bleeding.From the samples from liver,lung,kidney and other tissues of dead dolphins,we obtained a dominant strain from the lungs.The dominant strains were identified by colony morphology observation,gram stain microscopy,biochemical tests,PCR amplification,sequence alignment and phylogenetic trees.The identified dominant strain was Aeromonas hydrophila.The isolated strains were used for animal regression experiments.The results showed that SPF mice inoculated with bacterial liquid showed symptoms such as depression and abdominal circumference,and died 4 hours after in inoculation,all died after 16 hours.Lung and intestinal bleeding,and hepatic and renal hemorrhage were observed.The colony morphology,microscopic examination results,biochemical identification result and the DNA sequence of the strain recovered from the liver,kidney and lung were identical to the target bacteria.The susceptibility test showed that the strain was extremely sensitive to florfenicol,enrofloxacin,norfloxacin,gentamicin and kanamycin.The strain was highly sensitive to ampicillin and erythromycin and the strain had low-sensitivity to sulfadiazine and tetracycline.The results of this test provide a scientific basis for the prevention and control of the rest of the same group of dolphins in Kunming aquarium.