肺炎克雷伯菌短尾噬菌体LH-01药代动力学研究

Pharmacokinetics of the Podoviridae phage LH-01 in mice infected with Klebsiella pneumoniae

目的探讨噬菌体LH-01在小鼠体内的药代动力学及其影响因素。方法观察LH-01在小鼠体内的代谢过程和LH-01中和抗体产生规律。建立小鼠败血症感染模型,使用高剂量和低剂量LH-01进行治疗,观察小鼠健康评分（0~5）,同时检测小鼠外周血和主要脏器内活菌数和噬菌体滴度变化规律。结果噬菌体LH-01在小鼠体内具有较低的清除率,活性噬菌体可在小鼠体内持续存在数天,10d后完全消失。2周时外周血LH-01中和抗体效价为1：8,5周时最高为1：1 024。用高剂量组（10^10 PFU/ml）和低价量（10^4 PFU/ml）的噬菌体LH-01尾静脉注射治疗小鼠败血症,两组组小鼠健康评分最终差异无统计学意义（P〉0.05）,最终生存率均为100%,而对照组为0%。治疗组小鼠外周血和脏器（肝脏、脾脏和肺脏）中的菌落数显著少于对照组菌落数（P〈0.01）,尤以脾脏中菌落数减少最显著。LH-01治疗中具有自我放大效应,高剂量和低剂量治疗组小鼠外周血、肝脏和肺脏中的噬菌体滴度与噬菌体对照组相比均显著升高（P〈0.01）,尤以外周血增加最为明显。结论 LH-01具有杀菌效率高、自我增殖能力强、活性维持时间长、中和抗体产生晚等良好的药代动力学特性,可试用于多重耐药肺炎克雷伯菌感染的治疗。

Objective To investigate the pharmacokinetics of the phage LH-01 and factors influencing its pharmacokinetics in mice. Methods Changes in the pharmacokinetics of the phage LH-01 were observed in different tissues of mice,and the titer of phage-neutralizing antibodies in serum was also determined.After mice with pneumoniae-induced septicemia were treated with different doses of LH-01（high and low）,the health of those mice was assessed on a scale of0 to 5points.The number of phage particles and/or surviving bacterial cells in the organs（PFU/g or CFU/g）and blood（PFU/ml or CFU/ml）were measured. Results Phage LH-01 was still viable in vivo for up to 10 dbecause of its lower clearance rate by the reticuloendothelial system.The mean titer of LH-01 neutralizing antibody activity was 1：8in week2.The titer increased and peaked in week 5（1：1024）.Administration of a low dose（10^4 PFU/ml）or high dose（10^10PFU/ml）of LH-01 treated septicemia induced by K.pneumoniaein mice.There were no significant differences in the final assessment of the health of mice（P〉0.05）.Results also indicated that treatment with either dose of LH-01 significantly improved the survival of mice compared to the control group（100% survival vs.0% survival,P〈0.01）.LH-01 significantly decreased the bacterial burden in the blood and organs（lungs,liver,spleen,and kidneys）of mice after a K.pneumoniae challenge,and the bacterial count in the spleen decreased significantly（P〈0.01）.LH-01 can self-replicate in mice vivo.The phage titer was higher in the blood and organs（lungs,liver,spleen,and kidneys）of mice treated with LH-01 than in the control group.The phage count in the blood increased significantly（P〈0.01）. Conclusion LH-01 is highly efficient at killing bacteria,it is highly capable of self-replicating,it has a low clearance rate by the reticuloendothelial system,and it takes time to generate neutralizing antibodies in mice.The pharmacokinetic characteristics of LH-01 suggest that the phage shows promise as an efficient antibacterial agent,so this phage may be an alternative way to control multidrug-resistant K.pneumoniae.