一株裂解耐氨苄西林金黄色葡萄球菌的噬菌体及其生物学特性与全基因组分析

Biological Characteristics and Complete Genome Analysis of an Ampicillin-Resistant Staphylococcus aureus Phage

本研究旨在分离能够高效裂解耐药金黄色葡萄球菌的噬菌体,为噬菌体生物制品的研制提供候选材料。以耐氨苄西林金黄色葡萄球菌为宿主菌,用双层平板法分离噬菌体,通过透射电子显微镜观察噬菌体形态,并对其进行生物学特性分析及全基因组测序分析。结果分离得到一株金黄色葡萄球菌噬菌体,效价达2.75×10^(10)PFU/mL,命名为SP688。该噬菌体具有长的不收缩尾巴,属长尾噬菌体科,对7株耐氨苄西林金葡菌均有裂解效果,最佳感染复数为1,可在10 h内抑制细菌生长,在温度-20~54℃范围和pH值3~11之间活性稳定,对紫外线敏感。全基因组分析显示,SP688基因组为环状DNA,全长45499 kb,GC含量为34.1%;预测到64个开放阅读框(ORFs),其中19个(29.69%)被预测功能。该噬菌体是一株新型裂解耐氨苄西林金黄色葡萄球菌的广谱噬菌体,可为噬菌体治疗提供材料。

This study aimed to isolate phages with high efficiency for lysing drug-resistant Staphylococcus aureus,and to provide candidate materials for developing phage biological products.In this study,using ampi-cillin-resistant S.aureus as host bacterium,the phage was isolated by double-layer plate method,and then its morphology was observed by transmission electron microscopy,followed by biological characteristics and whole genome sequencing analyses.The results showed that a S.aureus phage with the titer of 2.75×10^(10) PFU/mL was isolated,named as SP688.The phage had a long uncontracted tail,which belonged to Caudovirales,the long tail phage family.It was capable of lysing 7 strains of ampicillin-resistant S.aureus with the optimal com-plex number of infection as 1;it could inhibit the bacterial growth within 10 hours with stable activity at-20℃to 54℃and pH 3~11;it was sensitive to UV.The length of SP688 whole genome was 45499 kb,defined as a circular DNA with GC content as 34.1%.A total of 64 ORFs were found,and 19 ones(29.69%)were predicted in function.This phage was a novel broad-spectrum one lysing ampicillin-resistant S.aureus,which might provide research material for phage therapy.