宽嗜性铜绿假单胞菌噬菌体的生物学特性及对临床菌株的嗜性覆盖研究

Study on Biological Characteristics and Coverage on Clinical Strains of Wide Tropism Pseudomonas Aeruginosa Phages

【目的】研究宽嗜性铜绿假单胞菌（PA ）的生物学特性，为临床控制PA感染提供思路。【方法】对5家医院下水道中分离出的PA噬菌体，采用双层琼脂噬菌斑形成法纯化后筛选出宽嗜性噬菌体，观察宽嗜性噬菌体的特征，绘制一步生长线，提取核酸行酶切分析。【结果】共分离出8株PA噬菌体，筛选出3株宽嗜性噬菌体，其中PAp-3表现出较宽的噬菌谱。电镜下PAp-3呈透明、圆形、边界清晰的菌斑；PAp-3基因组为23 kb ，当感染复数（MOI）为0．001时，其感染宿主产生子代PA噬菌体滴度最高，为6．4×10^10 PFU/mL ，感染宿主菌的潜伏期30 min ，爆发时间55 min ，裂解量100。3株宽嗜性噬菌体交叉组合对临床分离出的20株PA吞噬覆盖率为95．00％（19/20）。【结论】宽嗜性噬菌体具有较广的噬菌谱，潜伏期较短，裂解量大，交叉组合吞噬覆盖率高，可为噬菌体作为抗菌生物制剂提供依据。

Objective To explore biological characteristics of wide tropism pseudomonas aeruginosa （PA ） in order to provide the ideas for PA infection control .[Methods]PA phages were separated from sewer of five hospitals .After PA phages were purified by doubleagar negative colony formation method ,wide tropism phages were screened .The characteristics were observed and one-step growth line was drawn .Nucleic acid was extracted for enzyme digestion analysis .[Results] Totally 8 strains of PA phages were isolated .Three strains of wide tropism phages were screened ,in which PAp-3 showed wider phage spectrum .PAp-3 was transparent ,round and clear boundary plaque .PAp-3 genome was 23kb .When MOI was 0 .001 ,the titer of progeny PA phage produced by the infected host was highest（6 .4 × 10^10 PFU/mL） .The incubation period of the infected host bacteria was 30min ,and the outbreak time was 55min ,and the burst size was 100 .The engulfed coverage rate of cross combination of 3 wide tropism phages on 20 strains of the isolated PA phages was 95 .00% （19/20） .[Conclusion] Wide tropism phage has wider spectrum ,shorter incubation period large burst size ,higher engulfed coverage rate of cross combi-nation ,and can provide the basis for the phage used as antibacterial biological agents .