【摘要】 目的对产CMY型AmpC酶费劳地枸橼酸杆菌进行耐药表型及分子学特性进行研究,探讨研制新的酶抑制剂。方法对临床分离的两株费劳地枸橼酸杆菌所产CMY型AmpC酶用纸片扩散法、三相水解试验进行耐药表型检测,以该菌总基因组DNA和质粒DNA为模板进行PCR扩增、序列分析、质粒接合试验、构建重组表达载体及AmpC酶检测。结果两株菌株对青霉素类、头孢菌素类、喹诺酮类、氨基糖苷类抗生素均表现为耐药,对呋喃类和碳青霉烯类表现为敏感;三相水解试验结果显示该菌能水解头孢西丁;PCR扩增出大小为1 146 bp的基因片段,与GenBank上多种CMY亚型的基因序列同源性为97%;质粒接合试验证实质粒上含CMY基因,为可转移质粒。结论两株菌株所产CMY型AmpC酶为新的CMY型头孢菌素酶,它介导了该菌对青霉素类、头孢菌素类、喹诺酮类等抗生素耐药,其耐药性能水平传播。更多还原

【Abstract】 Objective To investigate the antibiotic phenotype and moleculelogy characteristics of novel CMY-type AmpC β-Lactamase from Citrobacter freundii,in order to triturate homologue enzyme inhibitors.Methods Slip diffusion method and three-phase hydrolyses test were used to analyze antibiotic phenotype of novel CMY-type AmpC β-Lactamase from Citrobacter freundii that was detached from clinic,The DNA and plasmid of CMY-type AmpCβ-Lactamase from Citrobacter freundii Strain was amplified by PCR、sequence analysis、Plasmid Conjugation tests、construction recombinant expression vector and AmpC induce tests.Results Two strains were resistant to penicillins,cephalosporin,quinolone,aminoglycoside,and susceptible to nitrofuran,carbapenem,The results of three-dimension test showed,AmpCβ-Lactamase from DNA Strain and recombinant strain could hydrolyz cefoxitin,The 1 146bp DNA fragment of CMY-type AmpC β-Lactamase encoding gene sequence shared 97 % amino acid identity with CMY-type AmpC β-Lactamase that already registered in GenBank.Plasmid Conjugation tests showed bla CMY located in plasmid and plasmid could conjugate.Conclusion The CMY-type AmpC β-Lactamase is a novel CMY-type AmpC cephalosporinase.It is resistant to penicillins,cephalosporin,quinolone,and it′s drug resistance can be transmissed.更多还原