耐碳青霉烯类弗劳地枸橼酸杆菌耐药机制及治疗策略研究

Study on drug resistance mechanism in carbapenem-resistant Citrobacter freundii and treatment strategies

目的探索耐碳青霉烯类弗劳地枸橼酸杆菌耐药机制及治疗对策。方法收集来自该院的17株耐碳青霉烯类弗劳地枸橼酸杆菌临床资料,采用PCR方法扩增碳青霉烯类耐药基因;采用琼脂稀释法和肉汤稀释棋盘法测磷霉素单药及联合用药最低抑菌浓度(MIC)值,计算部分抑菌浓度指数(ΣFICI)。结果 8株菌产blaNDM-1,9株菌产blaIMP,blaKPC、blaOXA-48、blaSPM均未检出;磷霉素联合亚胺培南协同作用和相加作用占75.00%,其中协同作用高达56.25%,磷霉素联合头孢哌酮/舒巴坦钠协同作用和相加作用占50.00%。结论磷霉素联合亚胺培南或头孢哌酮/舒巴坦钠体外有较好的抗菌活性,亚胺培南联合磷霉素效果可能更好。

Objective To explore the drug resistance mechanisms of carbapenem-resistant Citrobacter freundii （C. freundii） and its treatment strategies. Methods Clinical data of 17 strains of carbapenem-resistant C. freundii from this hospital were collect- ed. Carbapenemase resistant genes were amplifies by polymerase chain reaction （PCR）. The agar dilution method and the broth dilu- tion method were used to determine the minimal inhibition concentration （MIC） of single antimicrobial drug and drug combination, the partial inhibitory concentration index （Σ FICI） was calculated. Results Eight strains were found to produce blaNoM-1 and 9 strains produced blaIMP ,blaKPC ,blaSPM and blaoxn-48 were not detected in the study. Furthermore, the synergistic effect and addictive effect of fosfomycin combined imipenem accounted for 75.00% ,in which, the synergistic effect was up to 56.25 %. the synergistic effect and addictive effect of fosfomyein and cefoperazone/sulbactam accounted for 50.00%. Conclusion Fosfomycin combined with imipenem or cefoperazone/sulbactam has good antibacterial activity in vitro, but imipenem combined with fosfomycin may have bet- ter effect.