可形成生物膜的猪源奇异变形杆菌分离鉴定及致病性研究

Isolation and Identification of Biofilm-forming Protrus mirabils from Diseased Pigs and Its Pathogenicity

为确诊某猪场猪发病死亡原因,采集死亡猪病变组织,用常规方法分离鉴定细菌并进行致病性和耐药性检测。结果显示:从病死猪肺脏分离到1株奇异变形杆菌GX-PM1,与GenBank收录的奇异变形杆菌AYQ-1株同源性高达99.9%;小鼠致病性试验鉴定为强毒株:药敏实验检测结果显示,该菌株对阿米卡星、头孢氨苄为极敏,对青霉素G、头孢拉定、左氟沙星等为高敏,对阿莫西林、恩诺沙星等药物效果为中敏,对四环素、红霉素、复方新诺明、磺胺异恶唑等8种药物完全耐药;对耐药基因进行PCR扩增发现在该菌株中存在四环素类、氯霉素类、磺胺类耐药基因;GX-PM1株毒力基因型为ureC(-)、atfA(+)、pmfA (+)、zapA (+)、mrpA (-)、atfC (+)、ucaA (+)、rsbA (-);生物膜实验研究表明,分离株具有生物被膜形成能力,且为强黏附型(+++)。本研究表明此疫情由奇异变形杆菌引起,可用头孢类和氨基糖苷类药物进行治疗。

In order to investigate the causative agent of deaths on a pig farm,tissues from dead pigs were collected for virus isolation.As a result,Proteus mirabilis(GX-PM1) was isolated from diseased pigs,which was 99.9% homologous to Proteus mirabilis AYQ-1 strain deposited in GenBank.The isolated GX-PM1 strain was inoculated into mice and demonstrated to be pathogenic.The drug susceptibility testing showed that the isolate GX-PM1 strain was extremely sensitive to amikacin and cephalexin,highly sensitive to penicillin G,cefradine and levofloxacin,moderately sensitive to amoxicillin and enrofloxacin and completely resistant to 8 antibiotics such as tetracycline,erythromycin,compound neonomine,and sulfaisoxazole.The PCR testing revealed the presence of resistance genes to tetracycline,chloramphenicol and sulfa drugs.The virulence genotypes of GX-PM1 strain were ureC(-),atfA(+),pmfA(+),zapA(+),mrpA(-),atfC(+),ucaA(+),rsbA(-).In addition,the experiment showed that the isolate was able to form biofilms with strong adhesion type(+++).This study indicated that the pig deaths were caused by Proteus mirabilis and the infection could be treated with cephalo sporins and aminoglycosides.