银鲫不动杆菌病原菌鉴定及药敏试验

Identification and Drug Sensitive Test of the Pathogen in Acinetobacter Disease from Hybrid Crucian Carp(Carassius auratus gibelio♀× Cyprinus carpio♂)

从患病的异育银鲫体内分离到5株可疑菌株,经API 20NE细菌生化鉴定,YCS07-04株鉴定率为99.5%,T值符合率0.9,菌株鉴定为鲍曼不动杆菌。采用3种不同浓度进行感染试验,5.0×106cfu/ml浓度组注射感染14 d死亡率达100%,浸泡感染14 d死亡3尾;对照组未出现病症和死亡。菌株在营养琼脂菌落生长良好,在营养肉汤培养基中混浊,有菌膜及沉淀生长;血琼脂平皿菌落呈灰白色,直径2~3 mm,不溶血;麦康凯琼脂菌落半透明圆形;在SS琼脂培养基中不生长。经负染电镜观察,菌株末端圆形短杆状,偶尔可见不规则丝状体,大小为（1.0~1.5）μm×（1.5~2.5）μm,无芽孢、荚膜和鞭毛,表面凹凸不平,静止期呈球形。药敏试验表明,菌株对丁胺卡那霉素、链霉素、妥布霉素、庆大霉素、左氟沙星、复方新诺明和洛美沙星高度敏感;对四环素中度敏感;对羧苄青霉素、氧哌嗪青霉素、苯唑青霉素、头孢他啶、头孢噻肟、头孢哌酮、头孢三嗪和氨曲南等耐药。

Five bacteria were isolated from the visceral samples of moribund hybridized crucian carp（Carassius auratus gibelio♀×Cyprinus carpio♂）.The ID% and T value of the strain YCS07-04 identified as Acinetobacter baumannii was 99.5% and 0.9 by API 20NE.The artificial infection with three different concentrations showed that the high dosage group with 5.0×106 cfu/ml performed high infectivity and caused 100% mortality by injecting in 14 days.Three fish was dead of the bacterium immersing while the healthy fish without clinic disorder was observed in the control group.The isolated bacterium grew well in Nutrient Agar,cloudy with pellicle in nutrient broth,and showed gray white non-hemolytic colonies in rabbit blood agar and colorless transparent colonies on MacConkey agars,but did not live on SS agars.Negative staining under electron microscope revealed that the isolated bacterium was short straight rods with rounded ends in shape and（1.0～1.5）μm×（1.5～2.5）μm in size,becoming spherical in the stationary phase of growth,and to be big irregular filament when gathering.It has rough surface without flagellum,gemma and capsule.The isolated bacterium strain YCS07-04 was sensitive to streptomycin,tobramycin,gentamicin,levofloxacin,lomefloxacin and sulfamethoxazole compounds,and intermediate to tetracycline,while resistant to carbenicillin,ceftazidime,aztreonam and etc.