犬源奇异变形杆菌的分离鉴定及生物学特性、诱导结石形成能力研究

Study on identification, biological characteristic of Proteus mirabilis isolated from canine and its ability to induced calculus formation

为了评估引起犬结石病原菌的耐药性、致病性及诱导结石形成的能力,试验从泌尿系统结石反复发作、伴有血尿的宠物犬尿液中分离到1株细菌,并对其进行了革兰氏染色、培养特性分析、分子生物学鉴定、药敏试验、生物被膜形成能力和结石形成能力检测。结果表明:分离株为革兰氏阴性菌,无芽孢及荚膜,具有多形态性,呈杆状、球状;能产生脲酶分解尿素,具有溶血性,可迁徙生长;分离株16S rRNA基因核苷酸序列与参考菌株的同源性为99.1%~99.4%,证明为奇异变形杆菌;分离株仅对第四代头孢抗生素头孢吡肟敏感,对其他种类药物耐药;分离株能够形成生物被膜,使尿液产生大量结晶。说明犬源奇异变形杆菌具有较高的耐药性和致病性,可诱导形成结石,严重威胁人类健康。

In order to assess the drug resistance, pathogenicity and the ability to induce calculus formation of Proteus mirabilis, Proteus mirabilis was isolated from the urine of canine with infectious calculus and hematuria. Gram staining, culture characteristics analysis, molecular biological identification, antimicrobial susceptibility tests, ability of biofilm and urinary calculus formation of Proteus mirabilis were performed. The results showed that the bacteria was gram-negative bacteria without spore and capsule, and were polymorphic, rod-shaped and globular. The bacteria could produce urease to decompose urea, had hemolyticcand migratory. The nucleic acid sequence of the 16 S rRNA gene of the isolated strain was 99.1%-99.4% homology with the reference strain, which proved to be Proteus mirabilis. The isolated strain was only sensitive to the fourth-generation cephalosporin antibiotic cefepime and resistant to other kinds of drugs. The isolates could form a biofilm that produces a large amount of urine crystals. It indicated that Proteus mirabilis from canine had high drug resistance and pathogenicity, which could induce calculus formation and seriously threatened to human health.