医院感染革兰阴性杆菌产超广谱β-内酰胺酶、AmpC酶耐药性研究

Research on the drug resistance of Gram-negative bacillus producing ESBLs,AmpC enzyme in hospital infections

目的对医院感染常见的革兰阴性杆菌产超广谱β-内酰胺酶(ESBLs)、AmpC酶耐药性进行分析,为临床合理用药提供依据。方法收集住院部各科室临床细菌样本,用VITEK 2 Compact系统进行鉴定和药敏试验。采用药敏纸片法筛选产ESBLs、AmpC酶菌株。采用PCR通用引物扩增AmpC酶与ESBLs基因并进行序列测定以确定其基因亚型。结果 66株革兰阴性杆菌中产ESBLs酶的细菌以大肠杆菌为主(72.1%),其次为肺炎克雷伯菌(64.7%),产AmpC酶以铜绿假单胞菌及阴沟肠杆菌为主(均为100.0%),同时产ESBLs+AmpC酶以铜绿假单胞菌为主(33.3%)。检出4种ESBLs酶基因(TEM、SHV、OXA和CTX-M)、3种AmpC酶基因(DHA、CIT、EBC)。ESBLs中以CTX-M基因型检出率最高(62.1%);AmpC中以DHA基因型检出率最高(18.2%)。结论本院存在同时产ESBLs、AmpC酶革兰阴性杆菌流行株,上述临床常见病原菌携带多类药物钝化酶基因并存在不同的优势基因携带模式。

Objective To analyze the resistance of Gram - negative bacilli producing extended - spectrum β - lactamses （ ES- BLs） and AmpC in our hospital, so as to provid evidence for reasonable clinical administration. Methods Clinical bacteria samples were uollected from inpatient departments for identification and detection of drug sensitiveness using VITEK 2 Compact system. Disk diffusion test was used to screen the bacteria producing ESBLs and AmpC β- lactamses. PCR amplification was used to amplify the genes of ESBI.s and AmpC β- lactamses and theri sequencing to identify the gene subtypes. Results Among the 66 strains of Gram - negative bacillus, the highest incidence rate of ESBLs producing strain （72.1% ） was in Escherichia coli, followly 64.7% in the Klebsiella pneumoniae; the highest incidence rate of AmpC β-lactamases producing strains was 100.0% in Pseudomonas aeruginosa and Enterobacter cloacae, the incidence rate of both ESBLs and AmpC β- lactamases pro- ducing strain was 33.3% in Pseudomonas aeruginosa. 4 kinds of ESBLs genes（ TEM, SHV, OXA and CTX - M） and 3 kinds of AmpC β- lactamases genes（DHA, CIT, EBC） were detected. CTX- M（62.1% ） was the most popular genotype in ESBLs, and DHA （ 18.2% ） was the most popular genotype in AmpC. Conclusion There are epidemic strains of Gram - negative bacillus producing both ESBLs, AmpC β -lactamses in our hospital, and the bacterial isolates carry multiple kinds of inactive en- zyme encoding genes with different predominant gene - carrying models.