中文摘要：

分析rmtB阳性猪大肠埃希氏菌中氨基糖苷钝化酶的流行特点。设计10对引物,采用PCR、RFLP和测序等方法检测分析rmtB阳性猪大肠埃希氏菌中的10种氨基糖苷钝化酶基因。采用微量稀释法测定rmtB阳性猪大肠埃希氏菌及其接合子对10种氨基糖苷类的敏感性。48株rmtB阳性猪大肠埃希氏菌中检测到7种氨基糖苷类钝化酶基因,检出率从高到低依次是aac（3）-Ⅱ（85.8%）、aph（3′）-Ⅶ（77.6%）、aph（3′）-Ⅱ（77.6%）、aadA1（34.7%）、aac（6′）-Ⅰb（14.3%）、aac（3）-Ⅳ（10.2%）和aph（4）-Ⅰ（8.2%）;48株rmtB阳性猪大肠埃希氏菌对卡那霉素、阿米卡星、庆大霉素、妥布霉素、西索米星、萘替米星、新霉素、链霉素、大观霉素及安普霉素的耐药率分别为100%、100%、100%、100%、100%、100%、79.2%、77.1%、89.6%和27.1%。其对氨基糖苷类抗菌药的耐药表型与钝化酶基因型的符合率最高约98%。研究结果表明,氨基糖苷钝化酶广泛存在于rmtB阳性猪大肠埃希氏菌中,它们与其他氨基糖苷类耐药机制共同介导受试菌对氨基糖苷类抗菌药的耐药性。

英文摘要：

To analyse the prevalent characterization of aminoglycosides modifying enzymes in rmtB-positive Escherichia coli from pig farms.The polymerase chain reaction（PCR）,restriction fragment length polymorphism（RFLP） and DNA sequencing were used to detect and identify the resistant genes encoding aminoglycoside modifying enzymes.Micro-dilution method was adopted to evaluate the MICs to 10 aminoglycosides.Total of 7 aminoglycoside modifying enzymes were presented in 48 rmtB-positive Escherichia coli from pig farms.And the present ratio of aac（3）-Ⅱ,aph（3′）-Ⅱ,aph（3′）-Ⅶ,aadA1,aac（6′）-Ib,aac（3）-Ⅳand aph（4）-Ⅰwere 85.8%,77.6%,77.6%,34.7%,14.3%,10.2% and 8.2% by turn.The resistant ratio of the 48 rmtB-positive Escherichia coli to Kanamycin,Amikacin,Gentamycin,Tobramycin,Sisomicin,Netilmicin,Neomycin,Streptomycin,Spectinomycin and Apramycin were 100%,100%,100%,100%,100%,100%,79.2%,77.1%,89.6% and 27.1% respectively.The highest coincidence was 98% between the phenotypes to aminoglycosides and genotype of AMEs.It indicated that aminoglycoside modifying enzymes were prevalent in rmtB-positive Escherichia coli.They mediated the resistance of Escherichia coli to aminoglycosides with 16S rRNA methylase-RmtB.