大肠杆菌O157:H7烈性噬菌体SF08的分离、表征及在食品中的应用

Isolation,Characterization and Application in Food of Escherichia coli O157:H7 Virulent Bacteriophage SF08

本研究通过双层平板法从湖水中分离、纯化出一株大肠杆菌O157:H7烈性噬菌体,并命名为SF08。对其生物学特性、基因组序列及在即食鸡爪中的抑菌效果进行分析。结果表明,SF08由长约124 nm的可收缩尾巴和直径约76 nm的多面体头部组成。最佳感染复数(Multiplicity of Infection,MOI)为0.01;潜伏期为20 min,裂解期为20~110 min,爆发量为66 PFU/cell;在pH 3~12和30~70℃条件下能保持较高的活性。基因组全长59704 bp,G+C含量为56.52%,共有72个开放阅读框(ORF)。SF08在4℃下可以极显著地抑制即食鸡爪中模拟污染的大肠杆菌O157:H7(P<0.01)。本研究表明SF08具有较好的生物学特性及安全性,为后续研发和制备天然杀菌剂提供理论基础和参考。

In this study,a virulent bacteriophage of Escherichia coli O157:H7 was isolated and purified from lake water by double-layer agar plate method,and named SF08.The biological characteristics,genome sequence and antibacterial effect of SF08 in ready-to-eat chicken feet were analyzed.The results showed that SF08 was composed of a retractable tail about 124 nm long and a polyhedral head about 76 nm diameter.The optimal multiplicity of infection(MOI)was 0.01.The latent period was 20 min,the lysis period was 20~110 min,and the burst size was 66 PFU/cell.SF08 could maintain high activity under the range of pH(3~12)and temperatures(30~70℃).The total length of the genome was 59704 bp,the G+C content was 56.52%,and there were 72 open reading frames(ORFs).SF08 could significantly inhibit simulated contaminated Escherichia coli O157: H7 in ready-to-eat chicken feet at 4 ℃ (P<0.01) . This study shows that SF08 has good biologicalcharacteristics and safety,which provides a theoretical basis and reference for the subsequent development andpreparation of Escherichia coli O157:H7 natural fungicides.