论文部分内容阅读
目的了解肺炎克雷伯菌裂解性噬菌体PF23的生物学特性,观察其对小鼠全身感染的疗效。方法电镜观察噬菌体PF23的形态,一步生长曲线以及对温度和pH的敏感性;提取噬菌体基因组,酶切法鉴定其核酸类型,并初步估算其基因组大小;建立小鼠全身感染模型,观察PF23的治疗效果。结果 PF23的噬菌斑为有晕清晰透明圆斑,直径约2mm;电镜观察PF23具有尾噬菌体目,长尾病毒科病毒的形态特征;其在<50℃的温度下及pH 4~9范围内稳定性好。一步生长曲线显示其潜伏期约为11min,裂解量约为41PFU/细胞。其基因组核酸不能被双链DNA限制性内切酶KpnI、EcoRI和HindIII切开,但能被BamHI切开,且酶片段大小合计>27kb。用PF23治疗由其宿主菌所致全身感染小鼠,小鼠的生存期均>2d,7d存活率为37.5%;未治疗对照组小鼠1d内均死亡。结论肺炎克雷伯菌的噬菌体PF23潜伏期短,有较好的热稳定性和酸碱稳定性,治疗小鼠肺炎克雷伯菌全身感染效果显著,值得进一步研究。
Objective To understand the biological characteristics of Klebsiella pneumoniae lytic bacteriophage PF23 and to observe its curative effect on systemic infection in mice. Methods Phage PF23 morphology, one-step growth curve and its sensitivity to temperature and pH were observed by electron microscopy. The phage genome was extracted and its nucleic acid type was identified by enzyme digestion. The size of the genome was estimated. The model of systemic infection in mice was established and PF23 treatment was observed effect. Results The plaques of PF23 were clear and transparent circular halo with a diameter of about 2 mm. The morphological characteristics of PF23 were observed by electron microscopy. The results showed that PF23 had the morphological characteristics of the bacteriophage and monocytogenes. Under the temperature of 50 ℃ and pH 4 ~ 9 Good stability. The one-step growth curve shows that the incubation period is about 11 min and the amount of cleavage is about 41 PFU / cell. Its genomic nucleic acid can not be cleaved by the double-stranded DNA restriction enzymes KpnI, EcoRI and HindIII, but can be cleaved by BamHI, and the size of the enzyme fragment totals> 27kb. PF23 was used to treat systemic infection in mice caused by its host bacteria, the survival time of mice were> 2d, 7d survival rate was 37.5%; untreated control mice died within 1d. Conclusions The bacteriophage PF23 of Klebsiella pneumoniae has short incubation period, good thermal stability and acid-base stability. It is worthy of further study in the treatment of Klebsiella pneumoniae systemic infection in mice.