产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯杆菌耐药性分析及CTX-M酶的检测

Antibiotic resistance analysis and CTX-M enzyme detection of ESBLs-producing Escherichia coli and Klebsiella pneumoniae

目的分析北京地坛医院产超广谱β-内酰胺酶(extended-spectrum β lactamases,ESBLs)大肠埃希菌和肺炎克雷伯杆菌的耐药情况及其携带CTX-M酶的基因类型。方法对北京地坛医院2006年8月至2007年7月期间收集的无重复21例产ESBLs菌株,采用微量药敏定量实验检测20种抗生素的最小抑菌浓度,用针对CTX-M基因的特异性引物进行PCR扩增并确定其基因型,PCR产物进行克隆测序。结果21例菌株对大多数β-内酰胺类药物明显耐药,多数对氨基糖苷类和氟喹诺酮类耐药,但对亚胺培南100%敏感;产CTX-M酶的有10株,其中有7株产CTX-M-14酶,2株产CTX-M-3酶,1株产CTX-M-9酶。结论北京地坛医院2006年8月至2007年7月期间产ESBLs菌多为多重耐药菌,并且存在CTX-M酶的流行,主要是CTX-M-14酶和CTX-M-3酶。

Objective To investigate genotypes of CTX-M and resistance phenotype of ESBLs-producing Escherichia coli and Klebsiella pneumoniae isolated from Beijing Ditan Hospital.Methods The MICs of 20 antibiotics against 21 ESBLs-producing germs were determined by microquality and quantity analysis.CTX-M-type β-lactamase encoding genes were amplified by PCR.The nucleotide sequence of CTX-M encoding genes were characterized with automatic sequencer.Results Resistance to most β-lactams,fluoroquinolones and aminoglycosides antibiotics were found in 21 ESBLs-producing strains.No strain was found to be resistant to imipenem.Ten strains were investigated to produce CTX-M-type ESBLs,including CTX-M-14 (7 strains) and CTX-M-3 (2 strains),CTX-M-9 (1 strain).Conclusions Most of ESBLs-producing strains were multi-drug resistant and there were prevalence of CTX-M-type β-lactamases in Escherichia coli and Klebsiella pneumoniae isolated in Beijing Ditan Hospital from August in 2006 to July in 2007.Main genotypes of CTX-M of ESBLs-producing bacteria were CTX-M-14 and CTX-M-3.