产超广谱β-内酰胺酶肺炎克雷伯菌的分子流行病学研究

Molecular Epidemiology of Extended-spectrum β-lactamases producing Klebsiella pneumoniae

目的研究获得性肺炎(HAP)产超广谱β-内酰胺酶(ESBLs)肺炎克雷伯菌的耐药性及ESBLs基因型。方法回顾性分析18例感染产ESBLs肺炎克雷伯菌患者的临床资料,采用酶抑制剂增强法作ESBLs表型确证试验,纸片扩散法作药敏试验,聚合酶链反应(PCR)扩增ESBLs基因。结果产ESBLs肺炎克雷伯菌的阳性率为78.3%;仅对亚胺培南、美罗培南敏感;几乎所有患者均存在不规范使用抗生素、应用糖皮质激素、接受侵袭性操作等;SHV、CTX-M和TEM基因的阳性率分别为72.2%、61.1%和16.7%;44.4%的菌株同时携带多个基因。结论HAP产ESBLs肺炎克雷伯菌阳性率高、耐药情况严重,治疗应首选碳青霉烯类抗生素;不规范使用抗生素、应用糖皮质激素、接受各种侵袭性操作可能是其危险因素;最常见的ESBLs基因型是SHV,其次为CTX-M。

Objective To investigate the drug resistance and genotypes of extended-spectrum β-lactamases （ESBLs）-produeing Klebsiella （K.） pneumoniae isolated from patients with hospital acquired pneumonia （HAP）. Methods Clinical isolates of ESBLs-producing K. pneumoniae isolated from lower respiratory tract samples of 18 patients with HAP were studied retrospectively. Agar diffusion method was used to judge drug sensitivity. ESBLs were confirmed by inhibitor-potentiated test. ESBLs genotypes were analyzed by PCR. Results 78.3% of strains were considered ESBLs producers by phenotypic confirmatory test. These strains werc only sensitive to imipenem and meropenem, and the sensitive rate was 100%. Almost all cases had the following conditions： unreasonably using antibiotics. especially oxyiminβlactam antibiotics, using corticosteroids, applying invasivc operations. Of all ESBLs, 72.2% were positive for SHV, 61.1% for CTX-M and 16.7% for TEM. 44.4% of strains carried morc than one type of ESBLs. Conclusion The prevalence of ESBLs was high in K. pneumoniae isolated from patients with HAP in the department of neurosurgcry, and the resistant rates to most antibiotics were much higher. Carbopenems were the most effective antibiotics. Unreasonably using antibiotics, using corticosteroids, applying invasive operations might be the risk factors of ESBLs-producing K. pneumoniae. The most common ESBLs in K. pneumoniae were SHV, and the next was CTX-M in neurosurgery department.