克氏原螯虾副溶血性弧菌的分离鉴定与小鼠致病性试验

Isolation and Identification of Vibrio parahaemolyticus from Red Swamp Crayfish(Procambarus clarkia)and Its Pathogenicity in Mice

为探究从广西某养殖基地收集的患病克氏原螯虾(Procambarus clarkii)分离获得的一株细菌GXBL的致病性和生物学特性,利用形态学、分子生物学及生理生化综合鉴定菌株,进行分离菌感染实验动物、组织病理实验及药敏实验。结果显示,分离株GXBL在TCBS培养基上菌落呈蓝绿色、圆形,染色镜检为短棒状或弧状的革兰氏阴性菌;生理生化鉴定结果显示,分离菌能发酵阿拉伯糖、葡萄糖、甘露醇、尿素、精氨酸和甲基红,不能发酵纤维二糖、乳糖及蔗糖;16S rRNA序列分析显示该分离菌为副溶血性弧菌;动物试验结果显示,该分离菌对小鼠有一定的致病性,造成小鼠的肝细胞大片坏死,肝板结构被破坏,肺泡壁显著增厚,血管内聚集大量红细胞,脾脏淋巴细胞明显减少;药敏结果显示,分离菌对氨苄西林、头孢哌酮、庆大霉素、四环素、多黏菌素B、复方新诺明等18种抗生素敏感,对青霉素G、甲硝唑和氟康唑3种药物耐药。本研究结果可为副溶血性弧菌引起的克氏原螯虾细菌性疾病防治提供参考依据。

In order to investigate the pathogenicity and biological characteristics of bacterial strain GXBL isolated from diseased red swamp crayfish(Procambarus clarkii),the strain was comprehensively identified by morphology,molecular biology and physiological and biochemical tests,and the animal infection experiments,tissue pathology tests and drug sensitivity tests were carried out.The results showed that the colony of the isolated strain GXBL on TCBS medium was found to be blue-green and round,with short rod-shaped or arc-shaped Gram-negative bacteria by staining microscopy.The physiological and biochemical identification showed that the isolated bacteria fermented arabinose,glucose,mannitol,urea,arginine and methyl red,without fermentation of cellobiose,lactose and sucrose.The result of 16S rRNA sequence analysis revealed that the isolated bacteria were Vibrio parahaemolyticus.The animal tests showed that the isolated bacteria had certain pathogenicity to mice,resulting in massive necrosis of liver cells in mice,destruction of liver plate structure,significant thickening of alveolar wall,accumulation of a large number of red blood cells in blood vessels,and significant reduction of spleen lymphocytes.The drug sensitivity showed that the isolated bacteria were sensitive to 18 kinds of antibiotics such as ampicillin,cefoperazone,gentamicin,tetracycline,polymyxin B,and cotrimoxazole,and resistant to penicillin G,metronidazole and fluconazole.The findings provide a reference basis for the prevention and treatment of bacterial diseases caused by Vibrio parahaemolyticus.