南昌4家教学医院碳青霉烯类耐药肺炎克雷伯菌耐药机制及同源性分析

目的探讨临床分离的碳青霉烯类耐药肺炎克雷伯菌(CRKP)的耐药机制及同源性。方法收集南昌地区4家教学医院耐碳青霉烯类抗菌药物(亚胺培南和/或美罗培南)的肺炎克雷伯菌29株,双纸片增效法检测超广谱β-内酰胺酶(ESBLs)、三维实验检测AmpC酶、改良Hodge实验和双纸片协同法检测碳青霉烯酶,PCR扩增耐药基因,并对扩增产物测序,确定其基因型。脉冲场凝胶电泳(PFGE)对其进行同源性分析。结果 29株分离菌除对阿米卡星的耐药率较低(37.9%)外,对其他13种抗菌药物的耐药率均大于69%,其中对头孢呋辛、亚胺培南的耐药率为100%,多重耐药肺炎克雷伯菌的检出率为62.1%(18/29)。29株分离菌中有19株携带碳青霉烯酶基因,占65.5%(19/29),以blaKPC-2为主(44.8%,13/29),其次为blaNDM-1、blaIMP-26及blaIMP-4,携带率分别为17.2%(5/29)、10.3%(3/29)及6.9%(2/29),另有3株同时携带blaKPC-2和blaIMP-26,1株同时携带blaKPC-2和blaIMP-4。17株除携带碳青霉烯酶基因外,还携带ESBLs基因和(或)AmpC基因,占58.6%。未检测到VIM、GES、SPM及OXA等其他碳青霉烯酶基因。29株分离菌中有27株被PFGE成功分型,分别属于20个不同克隆,其余2株分型不成功。属于同一克隆型且携带blaKPC-2基因的4株菌来自同一医院。结论 CRKP耐药及多重耐药现象严重;携带碳青霉烯酶基因是肺炎克雷伯菌耐碳青霉烯类药物的主要原因,blaKPC-2携带率高,且在局部有短暂流行。本地区已监测到携带blaNDM的肺炎克雷伯菌,值得关注。

Drug-resistant mechanism and homology analysis of carbapenem-resistant Klebsiella pneumonia from four teaching hospitals in Nanchang city

Abstract: Objective: To investigate the drug-resistant mechanism and homology of carbapenem-resistant klebsiella pneumoniae (CRKP). Methods: Twenty-nine strains of CRKP, which were resistant to imipenem or meropenem, were collected from four teaching hospitals in Nanchang city. Then, ESBLs, AmpC and carbapenemases were detected by the double disc synergy test, three dimensional test and modified Hodge test, respectively. The drug-resistant genes and genotypes were determined by polymerase chain reaction (PCR) and DNA sequencing, respectively. The homology of these isolates was analyzed by pulsed field gel electrophoresis (PFGE). Results: The drug-resistant rates of 29 strains of CRKP were 37.9% for amikacin, 100% for cefuroxime and imipenem, and above 69% for other 11 antibacterials. The multidrug resistant rate of CRKP was 62.1% (18/29). Seventeen (17/29, 58.6%) strains of CRKP were positive for carbapenemase gene, and also carried ESBLs or AmpC gene. However, other carbapenemase genes such as VIM, GES, SPM and OXA were not detected. Nineteen (19/29, 65.5%) strains of CRKP carried carbapenemase genes, including 44.8% (13/29) of bla_KPC-2, 17.2% of bla_NDM-1, 10.3% of bla_IPM-26 and 6.9% of bla_IPM-4. In addition, there were 3 strains carried bla_KPC-2 and bla_IPM-26, and 1 strain carried bla_KPC-2 and bla_IPM-4. Twenty-seven of 29 strains of CRKP were successfully typed by PFGE and were grouped into 20 different bands. Four strains of CRKP carried bla_KPC-2 gene and the same band were from the same hospital. onclusion: The drug resistance and multidrug resistance of CRKP are serious. The primary cause of CRKP resisting carbapenem drugs is carrying carbapenemase gene, especially bla_KPC-2. It is worthy of attention that the Klebsiella pneumoniae carried bla_NDM gene is detected in Nanchang region.