肠杆菌科细菌SDD菌株特征及替加环素药敏结果分析

Characteristics of susceptible-dose dependent strains of Enterobacteriaceae bacteria and analysis of tigecycine sensitivity test results

目的分析医院肠杆菌科细菌剂量依赖性敏感（SDD）菌株的药物敏感性情况和检出分布特征,并检测产超广谱β内酰胺酶（ESBLs）大肠埃希菌和肺炎克雷伯菌对替加环素的敏感性,以指导临床对SDD菌株的抗菌药物及对ESBLs产酶株替加环素的选择。方法采用VITEK 2COMPACT全自动微生物分析仪进行细菌鉴定及仪器法抗菌药物敏感性试验。对50株ESBLs阳性大肠埃希菌和50株肺炎克雷伯菌分别采用微量肉汤稀释法、MTS测试条法、Vitek2仪器检测法、纸片扩散法检测替加环素的敏感性。结果采用M100-S24标准头孢吡肟判断为敏感的肠杆菌科细菌有3.58%~12.50%的菌株为SDD菌株;ESBLs阳性大肠埃希菌和肺炎克雷伯菌的SDD菌株检出率分别为13.31%和8.60%,显著高于ESBLs阴性菌株（P〈0.05）;所有肠杆菌科细菌SDD菌株最低抑菌浓度（MIC）4mg/L菌株检出率显著高于SDD菌株MIC 8mg/L菌株检出率（P〈0.05）;ESBLs阳性大肠埃希菌和肺炎克雷伯采用微量肉汤稀释法和MTS测试条法的敏感率均为100%。结论当肠杆菌科细菌头孢吡肟MIC为4mg/L或8mg/L时,实验室应在检验报告提示SDD菌株的检出。替加环素对ESBLs阳性大肠埃希菌和肺炎克雷伯菌的敏感率为100%。

Objective To analyze the drug susceptibility situation of susceptible-dose dependent（SDD）strains of Enterobacteriaceae bacteria and the detection distribution characteristics,and to detect the susceptibilities of extended spectrumβ-lactamases（ESBLs）producing Escherichia coli and Klebsiella pneumonia to tigecycline.Methods The bacterial identification and drug susceptibility test to antibacterial drugs were detected by adopting the VITEK 2COMPACT automatic microbiological analyzer.The susceptibility test to tigecycline in 50 strains of ESBLs positive Escherichia coli and 50 strains of Klebsiella pneumonia were tested by the mini broth dilution method,minimum inhibitory concentration（MIC）test strip,VITEK 2compact system and disk diffusion method,respectively.Results According to M100-S24 criteria,about 3.58%-12.50% of the Enterobacteriaceae strains susceptible to cefepime were SDD strains.For ESBLs positive Escherichia coli and Klebsiella pneumonia strains,the detection rate of SDD strains were 13.31% and 8.60% respectively,which were higher than those for ESBLs negative strains（P0.05）.Moreover,the detection rate of SDD Enterobacteriaceae strains for the MIC 4mg/L was higher than that for MIC 8mg/L（P0.05）;the sensitivity rate of ESBLs positive Escherichia coli and Klebsiella pneumonia to tigecycine by adopting the mini broth dilution method and the MIC test strip was 100%.Conclusion The laboratory should prompt that the SDD strain is detected out in the inspection report when the cefepime MIC is 4mg/L or 8mg/L.The sensitivity rate of tigecycline to ESBLs positive Escherichia coli and Klebsiella pneumonia is 100%.