新生儿中分离碳青酶烯类耐药肺炎克雷伯菌的耐药机制研究

Study on resistance mechanism of carbapenem-resistant Klebsiella pneumoniae separated from newborn patients

目的了解本院新生儿患者分离的碳青酶烯类抗生素耐药肺炎克雷伯菌的检出情况及耐药机制。方法收集本院2009年1月-2014年1月5年间分离的碳青霉烯类耐药肺炎克雷伯菌82株,采用改良Hodge试验及EDTA协同试验进行碳青霉烯酶表型的确认,用PCR方法扩增碳青霉烯酶基因(KPC、IMP、NDM、VIM、OXA-48),经电泳检测扩增产物后纯化测序。结果 82株碳青霉烯类耐药肺炎克雷伯菌主要分布在痰液和尿液标本中。耐药结果显示,对氨基糖苷类抗生素和氟喹诺酮类抗生素保持较高的敏感性。表型检测试验显示,32株改良Hodge试验阳性,8株EDTA协同试验阳性,经PCR确认发现,32株碳青霉烯类耐药肺炎克雷伯菌携带有blaKPC-2基因,8株携带blaNDM-1基因。结论本院新生儿分离碳青霉烯耐药肺炎克雷伯菌的比例较高,耐药性较强,主要以blaKPC-2基因介导,但也有blaNDM-1基因介导的"超级细菌"存在,应当引起临床重视。

Objective To investigate the detection and resistance mechanism of carbapenem - resistant KlebsieUa pneumoniae i- solated from newborn patients. Methods Eighty - two carbapenem - resistant Klebsiella pneumoniae isolates were collected from our hospital in five years from Jan. 2009 to Jan. 2014. The modified Hodge test and EDTA double - disc synergy test were used to detect the cabapenemase. Meanwhile, PCR was used to amplify the carbapenemase genes （KPC, IMP, NDM, VIM, OXA -48）, and all the PCR amplified and purified products were send to sequence. Results Eighty -two carbapenem -re- sistant Klebsiella pneumoniae were mainly isolated from sputum and urine, respectively. The results of the antimicrobial activity tests showed that the carbapenem - resistant Klebsiella pneumoniae isolates keep more sensitive to the aminoglycoside and flu- quinolone. Phenotypic confirmatory test showed that 32 isolates were positive to the modified Hodge test, while 8 isolates were positive to the EDTA - synergism test. The PCR confirmed that all 32 isolates positive to the the modified Hodge test carried the blaKPC - 2 gene, while the 8 isolates positive to the EDTA double - disc synergy test carried the blaNDM - 1 gene. Conclusion Carbapenem - rensistant Klebsiella pneumoniae was highly isolated from newborn patients in our hospital and the drug resist- ance was high. The resistance was mainly mediated by the blaKPC- 2 gene, but there also exist the “superbug” which media- ted by the blaNDM - 1 gene, which should be paid more attention to them by the clinic.