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目的观察肺炎克雷伯菌噬菌体LH-01治疗不同宿主菌所致小鼠败血症的效果,分析影响疗效因素,探索评价噬菌体疗效的方法。方法通过比较噬菌斑和成斑率,从9株LH-01宿主菌中选择对其敏感性较强的菌株。尾静脉注射绝对致死量的不同敏感菌致小鼠败血症,2h后通过尾静脉注射LH-01治疗并观察其疗效。比较LH-01在小鼠新鲜血清、补体热灭活血清,以及在标准补体溶血活性由低至高的溶液中对敏感菌的杀灭能力,明确引起LH-01对不同敏感菌感染组小鼠疗效差异的因素。结果 9株宿主菌中KP6、KP13、KP16和KP22在营养肉汤中对LH-01最为敏感。当小鼠全身感染致死量的这4种细菌后,LH-01的治疗可使KP6感染组小鼠生存率达90%(9/10),KP13组为30%(3/10),而KP16组和KP22组小鼠全部死亡。体外试验显示,除LH-01对KP6的作用不受补体影响外,LH-01对其余3株菌的杀灭作用均受补体影响,其中25U/ml的补体活性即可完全抑制LH-01对KP16和KP22的杀灭作用,而完全抑制对KP13的杀灭作用所需的补体活性≥50U/ml。结论补体是影响LH-01治疗小鼠肺炎克雷伯菌感染疗效的最主要原因。血清中噬菌体对致病菌的杀菌力和补体干扰杀菌的程度有助于预测噬菌体疗效,指导细菌感染的噬菌体治疗。
Objective To observe the effect of Klebsiella pneumophila phage LH-01 in treating sepsis induced by different host bacteria, analyze the influencing factors and explore the method to evaluate the phage efficacy. Methods By comparing the plaque and speckle formation rate, we selected 9 strains of LH-01 host strains that were more sensitive to them. Tail vein injection of absolute lethal dose of different sensitive strains of mice caused by sepsis, 2h after injection of LH-01 through the tail vein and observe its efficacy. Compared LH-01 in mice with fresh serum, complement heat inactivated serum, and in the standard complement hemolytic activity from low to high solution of the ability to kill sensitive bacteria, clearly caused LH-01 on different sensitive bacteria infected mice efficacy Differences in the factors. Results KP6, KP13, KP16 and KP22 were the most sensitive to LH-01 in the nutrient broth of 9 strains. LH-01 treatment resulted in a 90% (9/10) survival rate in KP6-infected mice and 30% (3/10) in KP13 mice when all four lethal doses of the systemic infection were induced in mice, whereas KP16 Groups and KP22 mice all died. In vitro tests showed that the killing effect of LH-01 on the remaining three strains was affected by complement, except that the effect of LH-01 on KP6 was not affected by complement. The complement activity of LH-01 at 25U / ml could completely inhibit LH-01 KP16 and KP22, while the complement activity required for complete inhibition of the killing of KP13 is ≥50 U / ml. Conclusion Complement is the most important factor affecting the therapeutic effect of LH-01 on Klebsiella pneumoniae in mice. The bactericidal effect of bacteriophages on pathogens and the degree of bactericidal interference of bacteriostasis in serum help to predict phage efficacy and guide bacteriophage treatment of bacterial infections.