硝羟喹啉联合美罗培南对碳青霉烯类耐药菌体外及小鼠体内药效学研究

In vitro antibacterial activity of nitroxoline combined with meropenem against carbapenem-resistant bacteria and the in vivo activity in mouse urinary tract infection model

目的探究硝羟喹啉在体外和小鼠体内提高碳青霉烯类耐药菌对美罗培南敏感性的方法。方法通过肉汤微量稀释法,测定硝羟喹啉对不同类型碳青霉烯类耐药菌(大肠埃希菌3株、肺炎克雷伯菌1株、鲍曼不动杆菌1株)和大肠埃希菌标准菌株ATCC 25922的最低抑菌浓度(MIC);利用扫描电镜,观察硝羟喹啉作用后细菌形态学改变。通过肉汤微量稀释棋盘法,计算硝羟喹啉和美罗培南的部分抑菌浓度指数(FICI);建立小鼠尿路感染模型,探索硝羟喹啉和美罗培南联合治疗对碳青霉烯类耐药菌感染的体内药效。结果硝羟喹啉单药在体外对标准菌株和临床耐药菌株均有一定抗菌活性,MIC范围1~4 mg/L;硝羟喹啉作用后,细菌表面出现不同程度的损伤,且与药物浓度呈正相关;回补Ca^(2+)或Zn^(2+)均使硝羟喹啉MIC值增加;硝羟喹啉与美罗培南联用,对产NDM-1耐药大肠埃希菌的FICI为0.1875,对产KPC-2型肺炎克雷伯菌和产OXA-23型鲍曼不动杆菌的FICI为2。在小鼠尿路感染治疗中,联合用药组小鼠尿液中细菌含量降低3.076 log10 CFU/mL,抗菌药效显著优于对照组和单药治疗组(P<0.0001)。结论硝羟喹啉可通过螯合二价金属离子,抑制细菌生长,也可以在体外和小鼠体内提高产NDM-1碳青霉烯类耐药大肠埃希菌对美罗培南的敏感程度。

Objective To investigate the effect of nitroxoline in restoring the susceptibility of carbapenem-resistant bacteria to meropenem in vitro and in vivo.Methods The minimum inhibitory concentrations(MICs)of nitroxoline against different carbapenem-resistant bacteria were determined by microdilution method.Scanning electron microscope was used to observe the morphological changes of bacteria after incubation with nitroxoline.The fractional inhibitory concentration index(FICI)of nitroxoline and meropenem was calculated by microdilution checkerboard assay.We established a mouse urinary tract infection(UTI)model using carbapenem-resistant bacteria to test the antibacterial efficacy of nitroxoline in combination with meropenem.Results Nitroxoline showed antibacterial activity against both the reference bacterial strain and resistant clinical isolates in vitro,with MIC ranging from 1 to 4 mg/L.After exposure to nitroxoline,the surface of bacteria demonstrated different degrees of damage,which was positively correlated with the concentration of nitroxoline.Replenishment of Ca^(2+)or Zn^(2+)could increase the MIC of nitroxoline.Nitroxoline combined with meropenem achieved FICI of 0.1875 for NDM-1-producing strain and 2 for KPC-2 or OXA-23-producing strain.In the mouse UTI model,nitroxoline combined with meropenem reduced the bacterial load in urine by 3.076 log10 CFU/mL.The antibacterial efficacy was significantly better than that of the control group and nitroxoline or meropenem alone(P<0.0001).Conclusions Nitroxoline can not only inhibit bacterial growth by chelating divalent metal ions,but also enhance the susceptibility of carbapenem-resistant bacteria to meropenem in vitro and in vivo.