中文摘要：

从某鸡场9日龄鸡群的粪便样本中分离、鉴定出奇异变形杆菌22株，并进行药敏试验和耐药基因（16SrRNA甲基化酶基因和超广谱G-内酰胺酶基因）的PCR检测。然后通过接合试验、电转化试验以及脉冲场凝胶电泳来分析16SrRNA甲基化酶基因的扩散机制。结果显示，22株鸡奇异变形杆菌对庆大霉素、阿米卡星、卡那霉素均呈现高水平耐药，对头孢噻呋、头孢噻肟、环丙沙星、氟苯尼考、多西环素呈现不同程度的耐药。PCR检测表明，在7种16SrRNA甲基化酶基因中仅扩增出rmtB基因；同时，这些菌株也携带有blaCTX-M基因。接合试验和电转化试验重复多次均未成功。脉冲场凝胶电泳结果显示，这些菌株具有相近的亲缘关系，提示该场鸡源奇异变形杆菌16SrRNA甲基化酶基因，rmtB的扩散以克隆传播为主。

英文摘要：

In order to clarify the dissemination mechanism of 16S rRNA methylase genes in Proteus mirabilis strains isolated from chickens, 22 Proteus m irabilis strains were isolated and identified from feces samples of the young chicken flocks in a chicken farm. Antimicrobial susceptibility tes- ting was performed by the broth dilution methods,and the resistant genes including 16S rRNA methylase genes and extended-spectrum beta-lactamase genes were detected by PCR. Then, the conjugation,transformation experiments and pulsed field gel electrophoresis（PFGE） were carried out to clarify the dissemination mechanism of 16S rRNA methylase genes in Proteus rnirabilis strains. The results indicated that all strains revealed the high-level resistant to gentamicin,amika- cin and kanamycin. In addtion,these strains also showed a different degree of resistance to ceftio- fur, ceftaxime,ciprofloxacin, florfenicol and doxycycline. PCR detection showed, of seven kinds of 16S rRNA methylase genes,only rmtB was positive. Moreover, these strains also carried blacTx M. Mutiple repeated attempts for conjugation and transformation experiments failed. The PFGE results indicated that these strains have a close clonal relationship, suggesting that the vertical spread is the main dissemination mechanism of 16S rRNA methylase gene rmtB in Proteus mirabilis strains isolated from chickens.