耐碳青霉烯类鲍曼不动杆菌噬菌体SH-Ab 15599的生物学特性及基因组学分析

Characterization and genome sequencing of SH-Ab 15599,a novel bacteriophage targeting carbapenem-resistant Acinetobacter baumannii

目的·寻找具有感染耐碳青霉烯类鲍曼不动杆菌(carbapenem-resistant Acinetobacter baumannii, CRAB)潜力的烈性噬菌体,进行生物学特性及基因组学分析。方法·采集污水,富集分离纯化得到噬菌体,通过电子显微镜观察噬菌体形态,研究其理化特征。抽取噬菌体DNA,进行测序和基因分析。结果·分离得到l株鲍曼不动杆菌噬菌体,命名为SH-Ab 15599。电子显微镜观察结果显示该噬菌体为肌尾噬菌体。SH-Ab 15599能够裂解51株CRAB临床分离株中的15株(29.4%);在4～50℃和pH值6～9的环境下,1 h内能保持活性;与宿主菌共培养5 min后,吸附率约为90%;其潜伏期约10 min,裂解期约20 min,每个细胞裂解量约43 pfu。在体外实验中,宿主菌的生长受到抑制。SH-Ab 15599的基因组为双链线状DNA,含143 204 bp,GC含量为38.45%。结论·SH-Ab15599是一株全新的噬菌体,具有治疗CRAB感染的潜力。

Objective · To fnd lytic bacteriophages which have potential to combat carbapenem-resistant Acinetobacter baumannii （CRAB） infections and analyze the biological characterizations and genomic sequences of the phages. Methods · The phages were isolated from sewage followed by amplifcation and purifcation. They were characterized by the transmission electron microscopy, the host specifcity, the biological characterizations, the lysis assay in vitro and the genome sequence analysis. Results · A novel bacteriophage, SH-Ab 15599, was isolated from sewage. The electron microscope revealed SH-Ab 15599 belongs to Myoviridae. Among the 51 clinical CRAB isolates tested, 15 （29.4%） were lysed by the phage. SH-Ab 15599 was relatively stable at temperature range from 4 ℃ to 50 ℃ or between pH 6 and 9. About 90% of the phage was approximately adsorbed to the host CRAB isolate in 5 min. The one-step growth curve showed that the latent period was about 10 min and the growth period was about 20 min. The burst size was estimated at 43 pfu per infected cell. The growth of the host CRAB isolate was inhibited by the phage in vitro. The genome of SH-Ab 15599 was a linear, 143 204 bp double-stranded DNA with GC content of 38.45%. Conclusion · SH-Ab 15599 is a novel phage targeting CRAB and has potential as an alternative against CRAB infections in the future.