Lee Cheonghoon, Choi In Young, Park Do Hyeon, Park Mi-Kyung
Department of Environmental Health Sciences, Graduate School of Public Health, Seoul, Republic of Korea.
2Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea.
J Environ Health Sci Eng. 2020 Feb 6;18(1):189-199. doi: 10.1007/s40201-020-00452-5. eCollection 2020 Jun.
O157:H7 is one of the major foodborne pathogens of global public concern. Bacteriophages (phages) have emerged as a promising alternative to antibiotics for controlling pathogenic bacteria. Here, a lytic O157:H7-specific phage (KFS-EC) was isolated, identified, and characterized to evaluate its potential as a biocontrol agent for O157:H7.
KFS-EC was isolated from slaughterhouse in Korea. Morphological analysis, genomic analysis and several physiological tests were performed to identify and characterize the KFS-EC.
A specificity test indicated KFS-EC was strictly specific to O157:H7 strains among 60 bacterial strains tested. Morphological and phylogenetic analyses confirmed that KFS-EC belongs to the genus, subfamily, and the family of phages. KFS-EC genome consists of 164,725 bp and a total of 270 coding sequence features, of which 114 open reading frames (ORFs) were identified as phage functional genes. KFS-EC does not contain genes encoding lysogenic property and pathogenicity, which ensure its safe application. KFS-EC was relatively stable (~1 log decrease) under stressed conditions such as temperatures (20 °C-50 °C), pHs (3-11), organic solvents (ethanol and chloroform), and biocides (0.1% citric acid, 1% citric acid, and 0.1% peracetic acid). KFS-EC was able to inhibit O157:H7 efficiently at a multiplicity of infection (MOI) of 0.01 for 8 h with greater inhibitory effect and durability and was stable at 4 °C and 22 °C over a 12-week storage period.
Our results suggest that KFS-EC could be used as a biocontrol agent to O157:H7.
O157:H7是全球公众关注的主要食源性病原体之一。噬菌体已成为控制病原菌的一种有前景的抗生素替代品。在此，分离、鉴定并表征了一种裂解性O157:H7特异性噬菌体（KFS-EC），以评估其作为O157:H7生物防治剂的潜力。
KFS-EC从韩国的屠宰场分离得到。进行了形态学分析、基因组分析和多项生理测试，以鉴定和表征KFS-EC。
特异性测试表明，在测试的60株细菌菌株中，KFS-EC对O157:H7菌株具有严格的特异性。形态学和系统发育分析证实，KFS-EC属于噬菌体的属、亚科和科。KFS-EC基因组由164,725个碱基对组成，共有270个编码序列特征，其中114个开放阅读框（ORF）被鉴定为噬菌体功能基因。KFS-EC不包含编码溶原性和致病性的基因，这确保了其安全应用。在温度（20°C - 50°C）、pH值（3 - 11）、有机溶剂（乙醇和氯仿）和杀菌剂（0.1%柠檬酸、1%柠檬酸和0.1%过氧乙酸）等应激条件下，KFS-EC相对稳定（约1个对数下降）。KFS-EC在感染复数（MOI）为0.01时，能够在8小时内有效抑制O157:H7，具有更强的抑制效果和持久性，并且在4°C和22°C下储存12周期间保持稳定。
我们的结果表明，KFS-EC可作为O157:H7的生物防治剂。
