羊源铜绿假单胞菌的分离鉴定与生物学特征分析

Isolation,Identification and Biological Characterization of Pseudomonas aeruginosa of Sheep Origin

为探究陕西省某羊场羊呼吸道疾病的主要病原,取该羊场8只病死羊的肺脏组织依次检测支原体、小反刍兽疫病毒、口蹄疫病毒和副流感病毒,结果均为阴性。无菌采集病死羊肺脏组织进行细菌学检测,经细菌分离培养、革兰氏染色镜检、生化试验与分子生物学鉴定,共分离到5株铜绿假单胞菌(分别命名为PA1~5),并对分离菌株进行小鼠致病性试验、药敏试验、生物被膜试验。结果显示,注射菌液的小鼠均在24 h内死亡,剖检发现小鼠肺脏、肝脏、脾脏出血肿大,且有大小不等、散在分布的化脓灶。药敏试验结果表明,PA1~5分离株对恩诺沙星、庆大霉素均敏感,对氨苄西林、阿莫西林、替米考星、氟苯尼考、泰乐菌素、泰万菌素、多西环素均表现耐药性。生物被膜试验表明PA1具有中等生物被膜形成能力,菌株PA2~5具有弱生物被膜形成能力。表明铜绿假单胞菌可能是造成本次羊呼吸道疾病的主要病原之一,且5株羊源铜绿假单胞菌分离株具有一定的致病性并可形成不同强弱程度的生物被膜,可交替使用恩诺沙星、庆大霉素进行治疗。研究结果可为铜绿假单胞菌引起的羊呼吸道疾病的防治提供参考。

In order to explore the main pathogen of respiratory tract diseases in a sheep farm in Shaanxi province,the lung tissues of eight sheep died from respiratory tract diseases were tested for Mycoplasma,PPRV,foot-and-mouth disease virus and parainfluenza virus,respective.However,all of the above pathogens tested were negative.Typical bacteria were isolated in the lung samples,identified morphologically,biochemically,and finally by 16S rDNA profiling.Five P.aeruginosa strains,isolated from eight lung samples eventually(PA1-5),were subjected to a pathogenicity test in mice,antimicbial sensitivity test,and biofilm-forming test.The results showed that the mice were dead after challenge with the isolates in 24 hours.At the time of necropsy,the lungs,livers,spleens appeared enlarged with hemorrhage and sometimes with necrotic foci.PA1-5 isolates were sensitive to enrofloxacin and gentamicin,and resistant to ampicillin,amoxicillin,temicoxin,florfenicol,taloxectin,tevanistin and doxycycline.The biofilm-forming test showed that PA1 had moderate biofilm forming ability and PA2-5 had weak biofilm forming ability.The present study revealed that P.aeruginosa infection is the leading cause of sheep death.Enrofloxacin and gentamicin can be used alternately for treatment.In conclusion,this study provides a guidance for the prevention and treatment of sheep respiratory diseases caused by P.aeruginosa.