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目的探讨碳青霉烯类耐药肠杆菌科细菌(CRE)的耐药机制及其在医院感染控制中的作用。方法选取2012年1月至2013年12月某院分离得到的肠杆菌科细菌5 604株,美罗培南抑菌环直径小于或等于20mm的细菌100株,经抗菌药物试验鉴定证实CRE共11株,进行耐药试验;使用微量肉汤法、改良Hodge试验、亚胺培南-乙二胺四乙酸(IPM-EDTA)复合纸片试验、IPM-EDTA双纸片试验、超广谱β-内酰胺酶(ESBLs)确证试验及AmpC试验来筛选耐药基因,应用PCR检测碳青霉烯酶的基因及阳性产物测序。结果 CRE菌株对头孢菌素类、青霉素类、碳青霉烯类及头孢西丁类等抗菌药物都表现出一定程度的耐药性,差异无统计学意义(P>0.05);PCR测序结果显示,blaIMP阳性菌株6株,均属于IMP-4型;blaKPC阳性菌株3株,均为KPC-2型;细菌耐药基因检测结果方面,筛查出1株携带2种碳青霉烯酶基因的肺炎克雷伯菌Kpn6617,其余筛查结果为阴性。结论产生碳青霉烯酶是细菌耐药的主要原因,IMP-4是主要酶型;应重视医院感染细菌耐药性特点,从而为临床合理用药提供参考。
Objective To investigate the drug resistance mechanism of carbapenem-resistant Enterobacteriaceae (CRE) and its role in nosocomial infection control. Methods A total of 5 604 strains of Enterobacteriaceae isolated from a hospital from January 2012 to December 2013 were selected and 100 strains of bacteria whose diameter was less than or equal to 20mm were collected from Meropenem. The drug resistance test was carried out using the micro broth method, the modified Hodge test, the IPM-EDTA composite paper test, the IPM-EDTA double paper test, the extended-spectrum β-lactam Enzyme (ESBLs) confirmatory test and AmpC test to screen drug resistance genes, PCR detection of carbapenemase gene and positive product sequencing. RESULTS: The CRE strains showed some resistance to cephalosporins, penicillins, carbapenems and cefoxitin antibacterials, with no significant difference (P> 0.05). PCR results showed that , blaIMP positive strains were 6, all belong to IMP-4 type; blaKPC positive strains of 3, are KPC-2 type; bacterial resistance gene test results, screening out a strain carrying two carbapenemase genes Klebsiella pneumoniae Kpn6617, the remaining screening results were negative. Conclusion Carbapenem is the major cause of bacterial resistance. IMP-4 is the main enzyme type. It should pay attention to the characteristics of drug-resistant bacteria in hospital infection and provide a reference for clinical rational drug use.