| 摘要: |
| 【目的】对福建梅花山华南虎繁育研究所一例华南虎幼虎急性死亡病例的致病菌进行分离鉴定及生物学特性研究，为圈养华南虎疫病防控提供科学依据。【方法】无菌采取死亡幼虎的肺、肝、脾、肠道等组织病料，进行细菌分离培养，根据形态特征、培养特性、生化试验、16S rRNA PCR扩增结果进行病菌鉴定；并对该分离菌进行16S rRNA系统进化分析、禽致病性大肠杆菌PCR鉴定、药敏试验、动物致病性试验和毒力基因检测。【结果】从幼虎肝脏及肠道组织中分离得到1株大肠杆菌（E.coli），命名为FJ/Tiger2016。16S rRNA系统进化分析显示，该分离菌与大肠杆菌人源分离株（NZCP016497）、鼠源分离株（NZMBNX01000003）、鸭源分离株（EF620926）及禽源分离株（AB272358）的遗传距离较近，形成一个相对独立的小遗传分支，其中与禽源分离株（AB272358）的同源性高达99.7％。PCR鉴定及药敏试验结果表明，该分离菌为禽致病性大肠杆菌（APEC），对选用的15种抗菌药均表现敏感。动物致病性试验结果显示，经腹腔接种时该菌株对试验小鼠具有较强的致病力，小鼠攻毒后5 h内全部死亡。病理剖检及组织病理切片观察结果表明，该菌株对死亡小鼠的心脏、肝脏和脾脏等多个重要组织器官均造成了较为严重的病理损伤，而经灌胃接种时试验小鼠均未出现明显的临床症状。毒力基因检测结果显示，该菌株含有10种毒力基因，暗示其可能具有很强的致病性。【结论】从死亡幼虎肝脏及肠道组织中分离到1株具有较强致病力、肠道外致病的禽致病性大肠杆菌，表明禽致病性大肠杆菌已对我国圈养华南虎造成了一定威胁，应引起重视。 |
| 关键词: 华南虎 禽致病性大肠杆菌 分离鉴定 生物学特性 |
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| 基金项目:国家自然科学基金青年科学基金项目（31602048）；福建省科技厅自然科学基金面上项目（2016J01712）；国家级大学生创新创业训练计划项目（201711312001）；福建省区域发展项目（2012Y3005）；龙岩学院校级协同创新中心项目；国家林业局野生动物疫源疫病监测和预警系统维护项目 |
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| Isolation,identification and biological characteristics of avian pathogenic Escherichia coli from South China tiger |
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FAN Kewei,YU Jia,YANG Shoushen,et al
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| Abstract: |
| 【Objective】Isolation,identification and biological characteristics of the pathogenic bacteria causing an acute death South China tiger cub in Fujian Meihuashan Institute of South China tiger breeding were studied to provide basis for prevention and control of the captive South China tiger disease.【Method】Sterile lung,liver,spleen and intestines samples of the dead tiger cub were collected for isolation and cultivation,and the isolates were identified according to morphological characteristics,culture characteristics and 16S rRNA PCR amplification.The isolates were identified by phylogenetic analysis of 16S rRNA,avian pathogenic Escherichia coli PCR,drug sensitivity test,animal pathogenicity test and virulence gene detection.【Result】An E.coli strain,named FJ/Tiger2016,was isolated from the liver and intestinal tissues.The 16S rRNA phylogenetic analysis showed that the isolate had a close genetic distance with strains from human (NZCP016497),rat (NZMBNX01000003),duck (EF620926) and poultry (AB272358),and formed a relative independent small genetic branch far from other strains.The isolate had 99.7％ homology with the strain from poultry (AB272358).The results of avian pathogenic E.coli PCR detection and drug sensitivity test showed that the isolate was an avian pathogenic E.coli,and it was highly sensitive to all of the 15 antimicrobial agents.The result of animal pathogenicity test showed that the isolate had strong pathogenicity to the experimental mice and all mice died within 5 h after intraperitoneal injection with it,and the pathological examination and histopathological observation results also showed that the isolate caused severe pathological damage to heart,liver and spleen and other important tissues and organs of the dead mice,while the mice in another group infected by intragastric administration had no clinical symptoms.The virulence gene detection showed that the isolate contained 10 of 17 virulence genes,suggesting that it may have a strong pathogenicity.【Conclusion】An avian pathogenic E.coli strain with strong pathogenicity and extraintestinal pathogenic characteristics was isolated from the liver and intestine tissues of the dead South China tiger cub.The results indicate that the avian pathogenic E.coli has certain threat to captive South China tigers in China. |
| Key words: South China tiger avian pathogenic Escherichia coli isolation and identification biological characteristics |
