多重耐药肺炎克雷伯菌Kp1503的ESBLs基因型分析

目的:了解广东汕头临床分离的产ESBLs肺炎克雷伯菌Kp1503株的耐药表型与基因亚型。方法:以琼脂稀释法测定Kp1503株对12种抗菌药物的MIC;设计TEM、SHV和CTX-M型全编码基因特异性引物,用聚合酶链反应(PCR)扩增获得其β-内酰胺酶编码基因,分别克隆入pMD18-T载体后测定其核苷酸序列,分析其基因亚型。结果:Kp1503株为多重耐药株,除对亚胺培南和环丙沙星敏感外,对庆大霉素、阿米卡星、四环素、头孢唑林、头孢他啶、头孢噻肟、头孢曲松、头孢吡肟、氨曲南、哌拉西林/三唑巴坦均耐药;其所携带的三种β-内酰胺酶基因序列分别与GenBank中TEM-1、SHV-12及CTX-M-3型编码基因序列的同源性为100%。结论:汕头地区存在同时产SHV-12、CTX-M-3型超广谱β-内酰胺酶及TEM-1型广谱β-内酰胺酶的多重耐药肺炎克雷伯菌。

Study on the ESBL-Encoding Genes in a Multi-resistent Klebsiella pneumoniae Isolate

Objective:To identify the resistant phenotype and genotype of the ESBL-producing Klebsiella pneumoniae strain Kp1503 isolated in Shantou, Guangdong. Methods: The MICs of twelve antibiotics against the strain Kp1503 were detected by agar dilution method. The β-lactamase-encoding genes were amplified by polymerase chain reaction (PCR) with specific primers designed for entire encoding gene of TEM-, SHV-, and CTX-M-type, then were sequenced and analyzed after cloned into pMD18-T vector respectively. Results: The strain Kp1503 is a multi-resistant strain, which was resistant to GEN, AMK, TC, CEZ, CAZ, CTX, CRO, CPE, ATM and PIP/TZB, but susceptible to IPM and CPLX, carrying three β-lactamase genes identified as TEM-1, SHV-12, and CTX-M-3 separately. Conclusion: There exists a multi-resistant K.pneumoniae isolate producing SHV-12 and CTX-M-3 extended-spectrum β-lactamases coexistent with TEM-1 broad-spectrum β-lactamase in Shantou area.