革兰阴性杆菌超广谱β-内酰胺酶基因型研究
Study on extended-spectrum β-lactmases genotype in gram-negative bacilli
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摘要:目的 分析革兰阴性杆菌中超广谱β-内酰胺酶(ESBLs)的基因型。方法 采用双纸片协同法筛选ESBLs菌, 用纸片扩散法检测其药敏结果, 分别用TEM、SHV和CTX-M通用引物进行PCR扩增并对PCR产物进行序列分析。结果 大部分产ESBLs菌对头孢噻肟耐药, 而对头孢他啶敏感, 少部分对两者都耐药, 这些菌株前者以CTX-M引物的PCR扩增结果, 主要为CTX-M-3, 还检出CTX-M-12、CTX-M-14;后者以SHV引物的PCR扩增结果, 主要为SHV-12, 还检出SHV-40、SHV-33和SHV-5型。TEM引物扩增结果全部为TEM-1型广谱酶。结论 革兰阴性杆菌中ESBLs主要是CTX-M-3型, 62.9%的菌同时存在2~3种酶。Abstract:Objective To study the ex tended-spectrum B-lactamases (ESBLs) geno type in gram-negative bacilli.Methods All of the ESBLs were screened by double disk synergic test and subjected to drug suscepitibitity test by K-B disk diffusion test.The initial typing was conducted by PCR amplification using TEM、SHV and CTX-M universal primers as well as sequence analysis on PCR products.Results Most of the ESBLs were resistant to cefotoxime and sensitive to ceftazidime.Least of them were resistant to both drugs.Within these strains, the former were mostly CTX-M-3 as well as CTX-M-12、CTX-M-14 type by PCR using CTX-M primers, the later were mostly SHV-12 as well as SHV-40、SHV-33 and SHV-5 type using SHVprimers.All of the strains were TEM-1 broad-spectrum β-lactamases using TEM primers.Conclusion The majority of ESBLs were CTX-M-3 genotype in gram-negative bacilli. There were 2-3 kinds of lactamases in 62.9% bacilli.
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