目的 对临床分离自同一患者不同部位的3株耐碳青霉烯类肺炎克雷伯菌进行耐药机制研究及同源性分析.方法 对某严重烧伤患者的股静脉导管尖端、创面分泌物及痰液标本中分离到的3株耐碳青霉烯类肺炎克雷伯菌,采用改良Hodge试验检测碳青霉烯酶,双纸片协同及增效试验检测金属β-内酰胺酶;PCR筛查耐药基因;肠杆菌科基因间重复序列-聚合酶链反应(ERIC-PCR)进行同源性分析,多位点序列分型技术(MLST)对肺炎克雷伯菌进行分子生物学分型.结果 3株耐碳青霉烯类肺炎克雷伯菌的改良Hodge试验均为阴性,双纸片协同及增效试验均为阳性;3株菌均检出blaNDM-1基因,而未检出blaKPC、blaGES、blaIMP blaSPM、blaVIM、blaGIM及blaOXA48等耐药基因;ERIC-PCR显示3株菌为同一型别,MLST分型结果显示3株菌均属于ST17型.结论 3株肺炎克雷伯菌对碳青霉烯类抗生素耐药的主要机制为携带blaNDM-1基因,且这3株菌为同一克隆.
Objective To investigate the drug resistant mechanism and homology of three strains of carbapenem-resistant Klebsiella pneumoniae (K.pneumoniae) isolated from different sites of one patient.Methods Three strains of carbapenem-resistant K.pneumoniae were isolated from femoral vein catheter tip,wound secretions and sputum of a patient with severe burns,respectively.Their carbapenemase,metallo-β-lactamase (MBL) and drug resistance genes were detected by modified Hodge test,double-disk synergy test and combination disk diffusion and PCR,respectively,and homology and biological typing were analyzed by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) assay and multilocus sequence typing (MLST) technology,respectively.Results The carbapenemase and MBL of three strains of carbapenem-resistant K.pneumoniae were negative and positive,respectively.The blaNDM-1 gene was identified from the three strains,but other drug resistance genes such as blanC,blaGES,blaIMP,blaSPM,blaVIM,blaGIM and blaOXA-48 were not detected.ERIC-PCR showed that three isolates belonged to the same genotype,and MLST showed that they were type ST17.Conclusion Carring blaNDM-1 gene is the main cause leading to the drug resistance of three strains of carbapenem-resistant K.pneumoniae,and they belong to the same genotype.