产ESBLs大肠埃希菌和肺炎克雷伯菌呼吸道分离株的基因分型及耐药性分析

目的了解深圳市人民医院大肠埃希菌和肺炎克雷伯菌呼吸道分离株超广谱β-内酰胺酶(ESBLs)的基因型特点及耐药性。方法采用临床实验室标准化协会(CLSI)推荐的表型确证试验筛选出该院呼吸道分离株产ESBLs大肠埃希菌和肺炎克雷伯菌共78株。应用PCR及DNA测序法分析产酶株的TEM、SHV及CTX-M3种β-内酰胺酶基因,用琼脂稀释法测定细菌最低抑菌浓度(MIC)。结果 37株产ESBLs大肠埃希菌中,28株(75.7%)检出CTX-M-14基因,4株(10.8%)检出CTX-M-9基因,其他型较少见。41株肺炎克雷伯菌中,25株(61.0%)检出SHV-12基因,4株(9.8%)检出SHV-11基因,其他SHV型较少。20株(48.8%)检出CTX-M-14基因,5株(12.2%)检出CTX-M-3基因,其他型较少。产ESBL菌株均对亚胺培南敏感,对氨苄西林/舒巴坦的耐药率最高(90%),对其他抗生素有不同程度耐药。结论深圳市人民医院呼吸道分离的产ESBLs大肠埃希菌以CTX-M-14型为主,产酶肺炎克雷伯菌以SHV-12和CTX-M-14型为最常见。

Genotype and antibiotic resistance of ESBLs-producing isolates from respiratory samples

Objective To understand the genotype characteristics and antibiotic resistance of extended spectrum β-lactamases（ESBLs） producing isolates from respiratory samples in Shenzhen People＇s Hospital.Method 78 ESBLsproducing Escherichia coli and Klebsiella pneumoniae isolates from respiratory samples were selected with phenotypic confirmatory test which was recommended by Clinical And Laboratory Standards Institute（CLSI）.PCR and DNA sequencing were used for TEM,SHV and CTX-M genes.The minimum inhibitory concentrations（MICs） of the bacteria were determined by agar dilution method.Result Among 37 ESBLs-producing Escherichia coli isolates,28（75.7%） and 4（10.8%） were detected as carrying CTX-M-14 and CTX-M-9 gene respectorely;other types were seldom.Among 41 ES-BLs-producing Klebsiella pneumoniae isolates,25（61.0%） and 4（9.8%） were found carrying SHV-12 and SHV-11 gene,respectively,and 20（48.8%） and 5（12.2%） were detected as having CTX-M-14 and CTX-M-3 gene respectively;other types of ESBLs were not common.All these ESBLs-producing isolates were sensitive to imipenem,and they showed higher resistance rate to ampicillin/sulbactam（90%）;these strains showed different degrees of resistance to other antibiotics.Conclusion The main genotype of ESBLs-producing Escherichia coli isolates from respiratory samples in Shenzhen People＇ s Hospital is CTX-M-14,but for those Klebsiella pneumoniae isolates,SHV-12 and CTX-M-14 are more common.