耐碳青霉烯类肺炎克雷伯菌的耐药基因检测

Detection of genotypes of carbapenem-resistant Klebsiella pneumoniaeisolates

目的了解耐碳青霉烯类肺炎克雷伯菌的耐药基因携带,以减少耐药菌的产生。方法对2009年1月-2012年2月耐碳青霉烯类肺炎克雷伯菌分离株进行筛选,鉴定和药敏采用VITEK-2Compact系统进行,引物特异性PCR法分别检测分离株的碳青霉烯酶耐药基因、ESBLs基因和AmpC等相关耐药基因的存在。结果共分离出6株碳青霉烯耐药或中介的肺炎克雷伯菌,其对青霉素类、青霉素/青霉素酶抑制剂、氨曲南、头孢菌素类、氨基糖苷类、氟喹诺酮类和碳青霉烯等抗菌药物表现为较高程度的耐药,但对替加环素有较高的敏感性;每一株菌均携带超广谱β-内酰胺酶基因,可检测到3-5个耐药基因;其中,1株菌经测序证实为携带blaIMP-4,并同时携带blaSHV、blaTEM和blaCTXG9基因;5株菌扩增到Ⅰ类整合子（intⅠ）;blaNDM及其他碳青霉烯类耐药基因筛查均为阴性。结论临床分离的碳青霉烯耐药或中介肺炎克雷伯菌的耐药表型和基因型基本相符,因而推测广泛耐药的肺炎克雷伯菌的主要类耐药机制与菌株同时携带产ESBLs、AmpC酶、碳青霉烯酶和Ⅰ类整合子（intⅠ）有关。

OBJECTIVE To investigate the resistant genes carried in the clinical isolates of carbapenem‐resistant K lebsiella pneumoniae in our hospital so as to reduce occurrence of resistant strains .METHODS The strain identi‐fication and antibiotic susceptibility test were carried out with VITEK‐2 compact system for the carbapenem‐resist‐ant K . pneumoniae strains isolated during Jan .2009 and Feb .2012 .The genotypes of carbapenem‐resistant genes ,ESBLs genes ,and AmpC were screened by specific PCR .DNA sequencing was performed to confirm geno‐types .RESULTS Six carbapenem‐resistant or mediated K .pneumoniae isolates were screened to be highly resist‐ant to penicillin ,penicillin/penicillin enzyme inhibitor ,aztreonam ,cephalosporins ,aminoglycosides ,fluoroquino‐lones and carbapenems ,but highly sensitive to tigecycline .All of 6 isolated strains produced one to three genes of ESBLs .And the blaIMP‐4 gene was confirmed in one （16 .6% ） of these isolates by DNA sequencing ,which also carried blaSHV ,blaTEM ,and blaCTXG9 .Five strains had to intⅠ genes .Detection of blaNDM and other car‐bapenem‐resistant genes were negative .CONCLUSION The resistant phenotype of clinical isolated carbapenem‐resistant or mediated K .pneumoniae is generally consistent with the genotype ,thus it can be presumed that the main resistance mechanism of extensive drug resistant K . pneumoniae is related to co‐carry of ESBLs‐producing gene ,AmpC enzayme ,carbapenemases and intⅠ .