| 摘要: |
| 为探索针对耐药沙门菌的噬菌体治疗方法，以沙门菌SE-21为宿主菌，从污水中分离得到一株烈性噬菌体并命名为vB_SalP_QS。在鉴定vB_SalP_QS生物学特性的基础上，对vB_SalP_QS和vB_SalP_SE29混合噬菌体治疗由沙门菌SE-21引起小鼠肠炎的治疗效果进行评价。结果表明：1）电镜观察可见该噬菌体属于有尾病毒目（Caudovirales），其效价为8×108 PFU/mL。2）vB_SalP_QS的最佳感染复数（MOI）为0.01，潜伏期为40 min，裂解期为50 min。温度为4~60 ℃具有较好的活性，在pH 4~pH 10范围内非常稳定。平板点滴法试验表明vB_SalP_QS可以裂解17株沙门菌，裂解率为44.7%。3）噬菌体vB_SalP_QS的全基因组测序分析显示，噬菌体vB_SalP_QS全长42 293 bp，GC含量为49%，共含有72个开放阅读框，且不含有溶源性、毒力因子及整合酶基因。4）小鼠体内治疗试验显示，宿主菌SE-21对小鼠最小致死量为5×108 CFU/mL，感染小鼠经vB_SalP_QS （100 μL 1×107 PFU/mL）和vB_SalP_SE29 （100 μL 1×107 PFU/mL）混合治疗后存活率为100%，单独用vB_SalP_QS治疗组 （200 μL 1×107 PFU/mL）的小鼠存活率为80%，单独用vB_SalP_SE29治疗组（200 μL 1×107 PFU/mL）的小鼠存活率为70%，对照组全部死亡。5）病理组织观察表明，混合噬菌体可以有效杀灭沙门菌SE-21的同时，还能更好地保护小鼠肠绒毛，可显著提高感染SE-21的小鼠存活率。综上，噬菌体vB_SalP_QS具有良好的酸碱稳定性、热稳定性以及安全性，混合噬菌体联合治疗效果优于噬菌体单一治疗。本研究为噬菌体制剂治疗沙门菌感染提供了重要依据，也为混合噬菌体鸡尾酒疗法的临床应用奠定基础。 |
| 关键词: 沙门菌 混合噬菌体 全基因组测序 生物学特性 治疗效果 |
| DOI：10.11841/j.issn.1007-4333.2024.09.08 |
| 投稿时间：2024-04-30 |
| 基金项目:2023年吉林省博士后优先资助项目；吉林农业大学国家级大学生创新创业训练计划项目；吉林省自然科学基金（20220101311JC） |
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| Biological characterization of Salmonella enterica phage vB_SalP_QS and treatment of Salmonella enteric infection in mice |
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LIANG Ruiqi1, HUANG Qixing1, WANG Lu1, WANG Shun1, BAI Huifang1, LI Jun1, AI Ze1, ZHANG Lei1,2
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| (1.College of Animal Science and Technology|College of Veterinary Medicine, Jilin Agricultural University, Changchun 130118, China;2.Changchun Borui Science & Technology Co., Ltd, Changchun 130051, China) |
| Abstract: |
| In order to study the phage therapy methods for drug-resistant Salmonella， a virulent bacteriophage was isolated from sewage with Salmonella SE-21 as the host bacterium and named vB_SalP_QS. On the baisis of identifying the biological characteristics of vB_SalP_QS， vB_SalP_QSand vB_SalP_SE29 hybrid phage for the treatment of enteritis in mice caused by SE-21 was evaluated. The results showed that： 1） The phage belonged to the order of caudoviruses （Caudovirales） by electron microscopy. The potency of the phage was 8×108 PFU/mL. 2） Biological characterization showed that the phage vB_SalP_QS had an optimal multiplicity of infection （MOI） of 0.01， with an incubation period of about 40 min， and a lysis period of about 50 min. It had good activity at temperatures ranging from 4 ℃ to 60 ℃， and it was very stable within the range of pH 4-pH 10. vB_SalP_QS could lyse 17 strains of Salmonella by The plate spot test. The cracking rate was 44.7%. 3） The phage vB_SalP_QS was 42 293 bp in total length， had a GC content of 49%， contained a total of 72 open reading frames （ORFs）， and had no lysogeny， virulence factors， and integrase genes.4） In vivo therapeutic tests in mice showed that the minimum lethal dose of the host bacterium SE-21 was 5 × 108 CFU/ mL， and the survival rate of infected mice treated with vB_SalP_QS （100 μL 1 × 107 PFU/mL） and vB_SalP_SE29 （100 μL 1 × 107 PFU/mL） was 100%. The survival rate of mice in the vB_SalP_QS treatment group （200 μL 1 × 107 PFU/mL） was 80%. The survival rate of mice in the vB_SalP_SE29 treatment group （200 μL 1 × 107 PFU/mL） was 70%. All control mice died. 5） Pathological observations showed that mixed phage could effectively kill Salmonella SE-21 and also better protect the intestinal villi of mice， which could significantly improve the survival rate of mice infected with SE-21. In conclusion， phage vB_SalP_QS has good acid-base， thermal stability as well as safety， and the therapeutic effect of mixed phage combination therapy is higher than that of phage monotherapy. This study provides an important experimental basis for the treatment of Salmonella infections with phage preparations and lays the foundation for the clinical application of mixed phage therapy. |
| Key words: Salmonella mixed phage whole-genome sequencing biological properties therapeutic effect |
