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目的从医院污水中分离粘质沙雷菌噬菌体,并分析其生物学特性,为进一步研究针对耐药性粘质沙雷菌的噬菌体制剂提供依据。方法采用双层琼脂平板法分离纯化针对粘质沙雷菌的裂解性噬菌体,观察噬菌体对宿主菌的裂解特异性,通过负染法电镜观察噬菌体的形态结构,提取噬菌体核酸进行酶切电泳,测定噬菌体的最佳感染复数和一步生长曲线,SDS-PAGE电泳初步分析噬菌体的结构蛋白和非结构蛋白。结果从医院污水分离出7株可裂解粘质沙雷菌的噬菌体,对其中一株噬菌体(命名为ФSM9-3Y)的生物学特征进行了初步研究。电镜显示噬菌体呈蝌蚪状,头部为20面体立体对称、直径约70 nm;尾部长约50 nm。ФSM9-3Y的最佳感染复数为1。一步生长曲线表明;ФSM9-3Y的潜伏期约30 min,暴发时间70 min,暴发量为629 PFU/cell。凝胶电泳显示噬菌体基因组为双链DNA、大小约54 kb。SDS-PAGE呈现至少包括13种蛋白,相对分子质量范围在25～130 kD,其中主要蛋白的相对分子质量约为48 kD。结论此次分离的噬菌体ФSM9-3Y为裂解性噬菌体,根据形态和结构特征,粘质沙雷菌噬菌体ФSM9-3Y属于有尾病毒目,肌尾噬菌体科。
Objective To isolate and purify the phage of Serratia marcescens from the hospital sewage and provide the basis for further study on phage preparations against drug-resistant Serratia marcescens. Methods The two-layer agar plate method was used to separate and purify the lytic bacteriophages against S. marcescens. The specificity of the phage to the host bacteria was observed. The morphological structure of the bacteriophages was observed by negative staining, and the phage nucleic acids were extracted for enzyme digestion electrophoresis. Phage best multiplicity of infection and one-step growth curve, SDS-PAGE electrophoresis preliminary analysis of phage structural and non-structural proteins. Results Seven isolates of Serratia marcescens were isolated from the hospital sewage and the biological characteristics of one of the phage (named ФSM9-3Y) were studied. Electron microscopy showed phage tadpole-like, the head is 20-sided stereo symmetry, a diameter of about 70 nm; tail length of about 50 nm. The best infection ФSM9-3Y complex number of 1. The one-step growth curve showed that the incubation period of ФSM9-3Y was about 30 min and the outbreak time was 70 min, with an outbreak of 629 PFU / cell. Gel electrophoresis showed that the phage genome was double-stranded DNA, about 54 kb in size. SDS-PAGE showed at least 13 kinds of proteins, the relative molecular mass range of 25 ~ 130 kD, in which the relative molecular mass of the major proteins is about 48 kD. Conclusion The isolated phage ФSM9-3Y is a lytic bacteriophage. According to the morphological and structural characteristics, the serotype ФSM9-3Y of Serratia marcescens belongs to the order of the tail virus and the myoblast phage.