摘要
【目的】大肠杆菌O157:H7(E.coli O157:H7)是一种重要的食源性致病菌。抗生素的不当使用导致E.coli O157:H7多重耐药和泛耐药成为一个日益严重的问题,研究其天然杀菌剂——烈性噬菌体,对于防控多重耐药E.coli O157:H7污染具有理论意义和实践应用价值。【方法】以多重耐药E.coli O157:H7为宿主菌,采用双层琼脂平板法,从污水中分离烈性噬菌体,对其生物学特性进行表征和全基因组序列分析,并评价该噬菌体应用于食品中对E.coli O157:H7的抑菌效果。【结果】成功分离纯化了一株可裂解E.coli O157:H7的噬菌体,命名为vB_EcoM_JN03(GenBank登录号:OR885871)。vB_EcoM_JN03属于有尾噬菌体目,肌尾病毒科;其最佳感染复数(MOI)为0.01,潜伏期为30 min,120 min后到达平稳期,裂解量80 PFU/cell;其在30~60℃和pH 4~12范围内效价稳定。vB_EcoM_JN03的基因组为双链DNA,全长158142 bp,G+C含量44.63%,编码206个开放阅读框(ORF),不含已知编码的毒力、抗生素耐药和溶源性基因。vB_EcoM_JN03在4℃下可显著抑制牛奶和牛肉样品中污染的E.coli O157:H7。【结论】经分离、鉴定的E.coli O157:H7烈性噬菌体vB_EcoM_JN03对宿主菌具有良好的抑制作用,有望作为一种天然杀菌剂防控E.coli O157:H7污染食品。
[Objective]E.coli O157:H7 is one of important foodborne pathogens.The improper use of antibiotics has led to E.coli O157:H7 multi-drug resistance and pan-drug resistance becoming an increasingly serious problem.The study of its natural bactericide,virulent phage,has theoretical significance and practical application value for the prevention and control of E.coli O157:H7 pollution.[Method]In this study,the multi drug resistant E.coli O157:H7 was used as the host bacteria,and the virulent phage was isolated from sewage by double-layer agar plate method.Its biological characteristics were characterized and the whole genome sequence was analyzed.The antibacterial effect of the phage on E.coli O157:H7 in food was evaluated.[Result]A phage capable of lysing E.coli O157:H7 was successfully isolated and purified,named vB_EcoM_JN03(GenBank accession number:OR885871).vB_EcoM_JN03 belongs to Caudovirales,Myoviridae.The optimal multiplicity of infection(MOI)was 0.01,the incubation period was 30 min,and it reached the plateau after 120 min.The burst size was 80 PFU/cell.It is stable in the range of 30-60℃and pH 4-12.The genome of bacteriophage vB_EcoM_JN03 is double-stranded DNA,with a total length of 158142 bp,G+C content of 44.63%,encoding 206 open reading frame(ORF),and does not contain known encoded virulence,antibiotic resistance and lysogenic genes.vB_EcoM_JN03 significantly inhibited E.coli O157:H7 in milk and beef samples at 4℃.[Conclusion]In this study,a virulent bacteriophage vB_EcoM_JN03 of E.coli O157:H7 was isolated and identified.It has good inhibitory effect on host bacteria and is expected to be used as a natural bactericide to control E.coli O157:H7 contaminated food.
作者
李天娇
舒梅
吴国平
钟婵
潘红
赵远洋
张玲
LI Tianjiao;SHU Mei;WU Guoping;ZHONG Chan;PAN Hong;ZHAO Yuanyang;ZHANG Ling(College of Food Science and Engineering,Jiangxi Agricultural University,Nanchang 330045,China)
出处
《江西农业大学学报》
CAS
CSCD
北大核心
2024年第3期713-725,共13页
Acta Agriculturae Universitatis Jiangxiensis
基金
国家自然科学基金地区项目(32160608、32360629)
江西省现代农业产业技术体系建设专项(JXARS-12)。
