摘要
目的研究阴沟肠杆菌染色质ampD基因及其高概率突变位点。方法从医院感染患者临床标本中分离阴沟肠杆菌,经头孢西丁初筛试验和头孢西丁三维试验确定是否产AmpCβ-内酰胺酶及其产酶类型,抽提产酶菌株染色质DNA,PCR扩增ampD基因并连接入pMD19-T载体,双链测序后与同种非突变标准菌株的ampD基因序列比对,并得到高概率突变位点。结果大部分产酶阴沟肠杆菌含有ampD基因,其中18株产持续高产型酶菌株的染色质中均扩增出ampD基因;阴沟肠杆菌ampD基因上有62个突变率高于50%的位点。结论产AmpCβ-内酰胺酶的阴沟肠杆菌染色质上均含有ampD基因;阴沟肠杆菌染色质ampD基因的高概率突变位点可能成为致持续高产酶的关键位点。
Objective To explore the genomic ampD and its mutation sites with high probability from Enterobacter cloacae. Methods The strains of Enterobacter cloacae were isolated from the nosocomial infectious patients in our hospital. The ability and the types of AmpC βproducing-lactamases were comfirmed by the improved Cefotaxime three dimensional test. The genomic DNA was extracted,and genomic AmpD was amplified by using PCR, then it was ligated into pMD19-T vector and sequenced. Mutation sites were analyzed by comparing with the AmpD sequence of the standard wild-type strains. Results Most parts of the strains conain genomic ampD. Among them, genomic ampD was amplified in all the clinical isolates pruducing durative high expressed AmpCβ-1actamases. The sequences of ampD were successfully obtained; Enterobacter cloacae contains 62 mutation sites, with the probability being over 50%. Conclusion All the strains of Enterobacter cloacae pruducing durative high expressed AmpC β-lactamases contain genomic ampD; the mutation sites with high probability may be the potential cause of pruducing durative-high-expressed AmpCβ-lactamases.
出处
《国际检验医学杂志》
CAS
2010年第1期11-12,15,共3页
International Journal of Laboratory Medicine
基金
上海市科委重点课题项目(No.054119509)
关键词
肠杆菌
阴沟
Β内酰胺酶类
基因
突变
Enterobacter cloacae
beta lactamases
Genes
Mutation
