耐碳青霉烯类鲍曼不动杆菌噬菌体的分离鉴定及其生物学特性

目的 通过分离耐碳青霉烯类鲍曼小动杆菌(CRAB)噬菌体,研究其生物学特性,为噬菌体治疗CRAB感染提供实验依据.方法 利用噬菌斑法从医院污水中分离CRAB噬菌体,电子显微镜观察噬菌体的形态特征,提取其基因组行酶切电泳,SDSPAGE分析噬菌体表面衣壳蛋白,测定噬菌体感染复数和耐受突变率,并观察其一步生长曲线.结果 筛选出1株具有较宽裂解谱的无尾双链DNA的CRAB噬菌体,命名为噬菌体AB3.其基因组大小约35 kb,表面主要衣壳蛋白相对分子质量约为35×103.该噬菌体感染宿主菌的潜伏期为20 min,爆发期为60 min,裂解量为350,耐受突变率为2.5×10-10,对pH值耐受范围广,热稳定性好.结论 噬菌体AB3具有较宽的噬菌谱,潜伏期短、裂解量大、耐受突变率低,对理化因素稳定性好,具有临床应用前景.

Isolation and biological characteristics of phages of carbapenem-resistant Acinetobacter baumannii

Objective To investigate the biological characteristics of phages of carbapenem-resistant Acinetobacter baumannii(CRAB),and provide new strategy for controlling CRAB infection.Methods Phages of CRAB isolated from raw sewage of a hospital were identified using the plaque method.The morphology of phages was observed by electron microscopy.The genome of phages was extracted for electrophoresis.The structural proteins of phages were analysed by SDS-PAGE.The optimal multiplicity of infection,resistant mutation rate and one-step growth curve of phages were determined.Results One CRAB-specific and tailless phage with double-stranded DNA was isolated,and was named as phage AB3.The size of phage AB3 genome was about 35 kb,and the relative molecular mass of major coat protein was 35×103.The incubation and burst periods of phage AB3 were 20 min and 60 min respectively,the burst size was 350,and the mutation rate of phage resistance was 2.5×10-10.The phage AB3 was stable to a wide range of pH and temperature.Conclusion Phage AB3 has relatively broad host range,shorter incubation period,apparent burst size,lower resistant mutation rate and good stability to physical and chemical factors,which leads to its promising prospect in clinical application.