产超广谱β-内酰胺酶肺炎克雷伯菌临床菌株耐药表型与基因型

Phenotypes and Genotypes of Clinical Isolates of ESBLs-producing Klebsiella pneumoniae

目的调查临床分离鉴定的产超广谱β-内酰胺酶(ESBLs)肺炎克雷伯菌的耐药表型与基因型的关系。方法以琼脂稀释法测定67株产ESBLs肺炎克雷伯菌对11种抗菌药物的MIC;应用PCR扩增其SHV、TEM和CTX-M型β-内酰胺酶编码基因,并对部分菌株的PCR产物进行克隆测序以确定其基因亚型。结果67株除未检出对亚胺培南耐药株外,对其他10种抗菌药物的耐药率在10.45%～89.55%,多重耐药率为74.63%;其中60株对氨基糖苷类耐药株和44株对β-内酰胺类耐药株的交叉耐药率各为88.33%和40.91%;67株SHV、TEM和CTX-M基因型检出率分别为91.04%、56.72%、28.36%,对其中7株克隆测序发现存在SHV-12、TEM-1及CTX-M-3基因亚型。结论67株产ESBLs肺炎克雷伯菌对除亚胺培南以外的大多数抗菌药物,呈现明显的多重耐药和交叉耐药,其中7株同时产SHV-12和CTX-M-3型超广谱和TEM-1型广谱β-内酰胺酶。

OBJECTIVE To investigate the relationship between phenotypes and genotypes of clinical isolates of ESBLs-producing Klebsiella pneumoniae. METHODS Agar dilution method was used to test the MICs of 11 antibiotics against 67 ESBLs-producing K. pneumoniae strains. PCR was performed for amplifying β-1actamaseencoding genes of SHV-, TEM-, and CTX-M-type, and the PCR products of some strains were cloned and sequenced to identify their gene serotypes. RESULTS With no imipenem-resistant strains among 67 strains, their resistant rates to 10 kinds of antibiotics were 10.45-89.55% The cross-resistant rates to aminoglycosides of 60 strains and to β-1actams of 44 strains were 88. 33% and 40. 91%, respectively. The positive rates of SHV-, TEM-, and CTX-M-type for 67 strains were 91.04%, 56.72% and 28.36%, respectively, and SHV-12, TEM-1 and CTX-M-3 genotypes were found in 7 strains by cloning and sequencing. CONCLUSIONS Sixty seven strains of ESBLs-producing K. pneumoniae present a clear feature of multi-resistance and cross-resistance to most of antibiotics except imipenem, among them there are 7 strains producing SHV-12 and CTX-M-3 extended-spectrum β-1actamase coexistent with TEM-1 broad-spectrum β-1actamase.