秀丽隐杆线虫—泛耐药鲍曼不动杆菌感染模型用于外排泵抑制剂逆转环丙沙星耐药的研究

摘要

目的 建立秀丽隐杆线虫-泛耐药鲍曼不动杆菌感染模型,用于外排泵抑制剂(EPIs)逆转泛耐药鲍曼不动杆菌(XDR-AB)对于环丙沙星耐药的研究.方法 建立秀丽隐杆线虫-泛耐药鲍曼不动杆菌感染模型,选用6种EPIs(CCCP、PAβN、NMP、奥美拉唑、利血平和维拉帕米)与氟喹诺酮类药物环丙沙星联合使用,记录秀丽隐杆线虫生存率以评价体内药效,同时进行毒性试验及体外药敏试验.结果 不同浓度XDR-AB对秀丽隐杆线虫的致死情况不同,选择5×106CFU/mL作为XDR-AB感染秀丽隐杆线虫浓度.秀丽隐杆线虫生存实验显示,XDR-AB感染线虫3h后线虫组与加入多粘菌素B的对照组生存曲线比较,差异无统计学意义(x2 =3.154,P＞0.05),感染线虫6、9h,与对照组比较,差异均有统计学意义(均P＜0.001),但感染6h与9h组的生存曲线比较,差异无统计学意义(x2=0.669,P＞0.05),最终选择6h作为感染时长,36 h为合适的抗菌药物治疗时长.环丙沙星联合EPIs应用于感染模型实验中,低浓度的PAβN、NMP、奥美拉唑、利血平可将线虫存活率分别提高30％～40％、15％～20％、20％～30％、20％,高浓度的维拉帕米可将感染线虫的存活率提高30％左右.体外药敏试验和毒性试验结果显示,环丙沙星分别与CCCP、奥美拉唑和维拉帕米联合可降低MIC至原来的1/4,分别联合PAβN,NMP和利血平可降低MIC至原来的1/2,其中CCCP体外联合抑菌效果最佳,但毒性较大不适于体内药效研究.结论 首次成功构建了秀丽隐杆线虫-泛耐药鲍曼不动杆菌感染模型,得到6种EPIs逆转环丙沙星耐药性的初步研究.%Objective To establish an extensively drug-resistant Acinetobacter baumannii (XDR-AB) infection model using Caenorhabditis elegans (C.elegans),and evaluate the effect of efflux pump inhibitors(EPIs) on reversal of ciprofloxacin resistance in XDR-AB.Methods XDR-AB infection model of C.elegans was established,six EPIs(CCCP,PAβN,NMP,omeprazole,reserpine,and verapamil)combined with ciprofloxacin were used to treat the infected model,the survival rate of C.elegans was recorded to evaluate the in vivo activities of drugs,toxicity test and in vitro drug susceptibility test were also performed.Results Lethal effect of different concentrations of XDR-AB on C.elegans was varied,5 × 106 CFU/mL of XDR-AB was selected to infect C.elegans.C.elegans survival test showed that survival curves of C.elegans infected with XDR-AB for 3 hours and curves of control group (polymixin B was added) were not significantly different (x2 =3.154,P＞0.05);compared with control group,survival curves of C.elegans infected with XDR-AB for 6 hours or 9 hours were significantly different (both P＜0.001),but 6 hours and 9 hours were not significantly different(x2 =0.669,P＞0.05),6 hours was chosen as the duration of infection,36 hours was appropriate for the duration of antimicrobial therapy.Ciprofloxacin with EPIs for infection model revealed that low concentration of PAβN,NMP,omeprazole,and reserpine could improve the survival rate of C.elegans by 30％-40％,15％-20％,20％-30％,and 20％ respectively,high concentration of verapamil could improve the survival rate of infected C.elegans by about 30％.In vitro susceptibility test and toxicity test results showed that ciprofloxacin combined respectively with CCCP,omeprazole,and verapamil could reduce minimum inhibitory concentration(MIC) to the original 1/4,combined respectively with PAβN,NMP,and reserpine could reduce MIC to the original 1/2,CCCP had the best bacterial inhibitory effect in vitro,but the toxicity was large,and was not suitable for the study of pharmacodynamics in vivo.Conelusion The infection model of C.elegans XDR-AB is initially and successfully established,which is used to evaluate the efficiency of six EPIs for reversing ciprofloxacin resistance.