亚胺培南耐药的铜绿假单胞菌中oprD基因突变研究

目的 研究耐哑胺培南(IMP)铜绿假单胞菌(Pa)外膜孔蛋白oprD基因突变方式和突变意义.方法 对来自临床样本的34株耐IMP的Pa用PCR方法直接扩增oprD基因,扩增产物纯化后进行DNA双向序列分析,测得序列在www.ncbi.nlm.nih.gov/BLAST中的BLASTn(序列号:X63152.1 Pseudomonas aeruginosa PA01)和BLASTx(序列号:NF249649.1 Pseudomonas aeruginosa PA01)进行DNA序列和氨基酸序列分析,并与标准菌株ATCC27853和2株临床分离IMP敏感Pa比较,分析突变类型和可能影响的oprD外膜蛋白功能域.结果 oprD基因突变率高达92.3%(12/13),突变方式多样(包括点突变、缺失突变、插入突变),导致外膜蛋白oprD L2、L3茎环结构上103、115、127、154、158、170、185、186、189位氨基酸改变和(或)移码突变.发现新的碱基变异位点(1 079、1114、1196、1206、1288、1300、1301 bp)和新的氨基酸突变位点(115、127、154、158、185、189位氨基酸).以上突变在标准菌株ATCC27853和2株临床IMP敏感的Pa中均未检测到.结论 oprD基因发生广泛有意突变,导致L2、L3茎环结构氨基酸改变和(或)移码突变,可能影响oprD与IMP结合,导致本组Pa对IMP耐药.

The investigation of mutation of outer membrance oprD gene in clinical imipenem resistant Pseudomonas aeruginosa

Objective To study the mutations of outer-membrane porin gerte (oprD) in imipenem-resistant Pseudomonas aeruginosa.Methods The PCR was applied to detect the oprD gene from the 34 clinical imipenem-resistant Pseudomonas aeruginosa.DNA sequence was proceeded to analysis the nuclentide sequence of the oprD gene and the deduced amino acid sequence.To analysis the mutation and the function of the oprD domain,those mutations were compaired with the standard Pseudomonas aeruginosa ATCC27853 and 2 clinical imipenem-susceptibility isolates.Results oprD gene mutation was wide and diverse.The rate of the mutation was 92.3% (12/13),mutations were concluded dot mutation,deletion mutation and insert mutation,those result in the amino sequence change and frame shift in L2 and L3 loops of outer membrane protein D,hampering the combine of oprD and imipenem.Some new mutations were found.They were 1 079,1 114,1 196,1 206,1 288,1 300,1 301 bases and 115,127,154,158,185,189 aminos.All above mutations were not deteced in ATCC 27853 and 2 clinical imipenem-susoeptibility isolates.Conclusions The wide and diverse mutations in oprD gene result in amino acid change and/or frame shift L2 and L3 loops,hampering the binding of IMP and oprD.Those may result in resistance to imipenem in Pseudomonas aeruginosa.