两所三级医院耐药鲍氏不动杆菌耐药元件检测研究

Comparison of resistant elements in drug resistant Acinetobacter baumannii isolated from two third-grade hospitals

目的比较两所医院鲍氏不动杆菌临床分离株耐药表型及耐药元件的差异,了解两所医院鲍氏不动杆菌耐药表型及分子流行病学特性。方法收集2011年1-12月患者临床标本中分离的39株耐药鲍氏不动杆菌,其中A1~A19号株分离自浙江省宁波市第二医院(A院),B1~B20号株分离自江苏省无锡市人民医院(B院);先用16S^23SrDNA鲍氏不动杆菌种特异PCR扩增做菌种的分子鉴定,再采用聚合酶链反应(PCR)法分析33种β-内酰胺酶基因、8种氨基糖苷类修饰酶基因、6种16SrRNA甲基化酶基因、12种可移动遗传元件遗传标记、2种氟喹诺酮类药物作用靶位基因,测得结果作样本聚类分析(UPGMA法)。结果 A院菌株对氨基糖苷类药物仍有较高的敏感性,B院菌株对常用药物均耐药;A院19株菌株均检出β-内酰胺类药物获得性耐药基因、可移动遗传元件遗传标记以及氟喹诺酮类药物作用靶位基因均存在突变,只有14株菌株未检出氨基糖苷类药物获得性耐药基因;B院20株菌株均检出β-内酰胺类药物获得性耐药基因、氨基糖苷类药物获得性耐药基因、可移动遗传元件遗传标记以及氟喹诺酮类药物作用靶位基因均存在突变;两所医院菌株耐药元件检测结果的样本聚类分析显示:A、B两所医院的菌株因检出基因不同则分成两簇,A院的14株为同一克隆,而B院的20株为同一克隆。结论可移动遗传元件介导获得性耐药基因可在细菌间传播,两所医院菌株的耐药表型和基因型一一对应,A院5株菌的表型与B院20株菌相同,但获得性耐药基因检测结果不同。

OBJECTIVE To compare resistant phenotype and resistant elements in drug resistant Acinetobacter baumannii（A.baumannii）isolated from two third-grade hospitals,so as to investigate the characteristics of resistant phenotypes and molecular epidemiology of A.baumannii isolated from the two third-grade hospitals.METHODS From Jan.to Nov.2011,19strains（strains A1-A19）of A.baumannii were isolated from Zhejiang Ningbo Second Hospital（hospital A）and 20strains（strains B1-B20）of A.baumannii were isolated from Jiangsu Wuxi People′s Hospital（hospital B）.Species-specific PCR amplification of 16S-23SrDNA of A.baumannii was performed to identify species.Then,33 kinds of beta-lactamase genes,8kinds of aminoglycoside modifying enzyme genes,6kinds of 16 SrRNA methylase genes,12 kinds of mobile genetic elements,2kinds drug target genes of fluoroquinolone were analyzed by PCR and verified by DNA sequencing.Finally,the sample cluster analysis was performed for all genes（UPGMA）.RESULTS Strains from hospital A showed high susceptibility to aminoglycosides,while strains from hospital B showed resistance to all common antimicrobials.Acquired beta-lactamase genes,mobile genetic elements were positive,and mutations existed in drug target genes of fluoroquinolone in all 19 strains,however,acquired aminoglycoside genes were negative in 14 strains from hospital A.In comparison,acquired beta-lactamase genes and acquired aminoglycoside genes,mobile genetic elements were positive,and mutations existed in drug target genes of fluoroquinolone in all 20 strains from hospital B.And the sample cluster analysis showed that2 clusters were divided：14strains from hospital A were the same clone,while 20 strains from hospital B were the other clone.CONCLUSION Acquired resistant genes mediated by mobile genetic element transmit resistance among strains.Phenotypes and genotypes of strains were homologous in strains isolated from the two hospitals.Phenotypes of 5strains from hospital A and 20 strains from hospital B were the same,but genotypes were different.