畜牧兽医学报 ›› 2021, Vol. 52 ›› Issue (3): 763-771.doi: 10.11843/j.issn.0366-6964.2021.03.020

• 预防兽医 • 上一篇    下一篇

鼠伤寒沙门菌烈性噬菌体的分离鉴定与生物学特性

何依蓉, 张奕杰, 杨伟, 陈晓聪, 张家翔, 陈培富*   

  1. 云南农业大学动物医学院, 昆明 650201
  • 收稿日期:2020-08-25 出版日期:2021-03-23 发布日期:2021-03-24
  • 通讯作者: 陈培富,主要从事预防兽医学研究,E-mail:cltwins2003@163.com
  • 作者简介:何依蓉(1996-),云南德宏人,白族,硕士生,主要从事预防兽医学研究,E-mail:1106111315@qq.com;张奕杰(1998-),四川成都人,硕士生,主要从事预防兽医学研究,E-mail:854584301@qq.com。
  • 基金资助:
    云南省专家工作站项目(202005AF150041);国家级大学生创新创业项目(201810676018)

Isolation, Identification and Biological Properties of a Lytic Phage against Salmonella Typhimurium

HE Yirong, ZHANG Yijie, YANG Wei, CHEN Xiaocong, ZHANG Jiaxiang, CHEN Peifu*   

  1. College of Veterinary Medicine, Yunnan Agricultural University, Kunming 650201, China
  • Received:2020-08-25 Online:2021-03-23 Published:2021-03-24

摘要: 旨在分离鼠伤寒沙门菌烈性噬菌体,为控制该病原菌感染或污染提供生物制剂。以1株从市售散装牛奶中分离到的多重耐药性鼠伤寒沙门菌为宿主菌,采用人工诱导方法,连续1周每日给3只试验鸡饲喂宿主菌悬液,7 d后,采用双层琼脂平板法从试验鸡粪便中分离培养噬菌体,并对其效价、核酸类型、宿主谱、热稳定性与酸碱耐受性以及对鼠伤寒沙门菌感染小鼠的治疗效果进行分析。结果表明:分离到1株鼠伤寒沙门菌噬菌体,命名为KM104。该病毒在体外高效裂解同源宿主菌株及另1株受试鼠伤寒沙门菌,形成清晰透明、直径约1 mm圆形噬菌斑,核酸类型为DNA,基因组约为28 kb,最佳感染比(MOI)为1∶10,对宿主菌感染的潜伏期约为6 min,70 min时效价最高,达4.6×108 PFU·mL-1,在20~60℃、pH2.0~8.0范围内保持较高的生物学活性,并有效减轻鼠伤寒沙门菌引起的小鼠十二指肠组织损伤。结果提示,噬菌体KM104能在体内外高效裂解鼠伤寒沙门菌,且增殖迅速,对环境适应性强,其耐酸特性利于抵御胃酸的分解,具有应用于生物防治的潜力。

关键词: 鼠伤寒沙门菌, 烈性噬菌体, 生物学特性, 生物防治

Abstract: Isolation of an appropriate lytic phage against Salmonella Typhimurium will help to provide a biological for controlling infection or pollution caused by this pathogen. A strain of Salmonella Typhimurium with multidrug resistance which had been isolated from bulk milk was used as host bacteria. Artificial induction method was employed. Three chickens were fed daily with the host bacterium suspension for a week. After 7 days, the phage isolation and culture was conducted from chicken feces by using double agar plate method. The titer, nucleic acid type, host spectrum, thermal and acid-base stability and therapeutic effect in Salmonella Typhimurium infected mice using the phage were analyzed. A lytic phage against Salmonella Typhimurium was isolated and purified, named KM104. This phage efficiently lysed the homologous host strain and another Salmonella Typhimurium strains in vitro, producing clear and circular plaques with a diameter of about 1 mm. The viral nucleic acid type was DNA and its genome size was 28 kb or so. The highest titer of the virus was 4.6×108 PFU·mL-1. The optimal multiplicity of infection (MOI) was 1:10, the incubation period was approximately 6 min, and it reached the highest titer at 70 min. The phage maintained high viability under the condition of 20-60℃ and a pH value range of 2.0-8.0. The phage effectively reduced the injury in duodenal tissue of experimental mice caused by Salmonella Typhimurium. The results here indicated that KM104 can efficiently lyse Salmonella Typhimurium in vivo and in vitro with rapid proliferation and strong adaptability to the environment. Its acid-fast character is expected to help resist the degradation by gastric acid, making the phage have a potential application value in preventing and controlling Salmonella Typhimurium infection or pollution.

Key words: Salmonella Typhimurium, lytic phage, biological properties, biological control

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