College of Animal and Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, Sichuan, China.
Key Laboratory of Veterinary Medicine of Universities in Sichuan, Chengdu, PR China.
BMC Microbiol. 2023 Aug 8;23(1):215. doi: 10.1186/s12866-023-02960-4.
Proteus mirabilis, a naturally resistant zoonotic bacterium belonging to the Enterobacteriaceae family, has exhibited an alarming increase in drug resistance. Consequently, there is an urgent need to explore alternative antimicrobial agents. Bacteriophages, viruses that selectively target bacteria, are abundant in the natural environment and have demonstrated potential as a promising alternative to antibiotics. In this study, we successfully isolated four strains of Proteus mirabilis phages from sewage obtained from a chicken farm in Sichuan, China. Subsequently, we characterized one of the most potent lytic phages, Q29, by examining its biological and genomic features. Comparative genomic analysis revealed the functional genes and phylogenetic evolution of Q29 phages. Our findings revealed that Proteus mirabilis bacteriophage Q29 possesses an icosahedral symmetrical head with a diameter of 95 nm and a tail length of 240 nm. Moreover, phage Q29 exhibited stability within a temperature range of 37 ℃ to 55 ℃ and under pH conditions ranging from 4 to 9. The optimal multiplicity of infection (MOI) for this phage was determined to be 0.001. Furthermore, the one-step growth curve results indicated an incubation period of approximately 15 min, an outbreak period of approximately 35 min, and an average cleavage quantity of approximately 60 plaque-forming units (PFU) per cell. The genome of phage Q29 was found to have a total length of 58,664 base pairs and encoded 335 open reading frames (ORFs) without carrying any antibiotic resistance genes. Additionally, genetic evolutionary analysis classified phage Q29 within the family Caudalidae and the genus Myotail. This study provides valuable research material for further development of Proteus mirabilis bacteriophage biologics as promising alternatives to antibiotics, particularly in light of the growing challenge of antibiotic resistance posed by this bacterium.
奇异变形杆菌是一种天然耐药的人畜共患病菌，属于肠杆菌科，其耐药性呈惊人增长。因此，迫切需要探索替代抗菌药物。噬菌体是一种选择性靶向细菌的病毒，在自然环境中大量存在，并且已被证明是抗生素的一种有前途的替代品。在本研究中，我们成功地从中国四川一家养鸡场的污水中分离出了四株奇异变形杆菌噬菌体。随后，我们通过研究其生物学和基因组特征，对其中一种最有效的裂解噬菌体 Q29 进行了表征。比较基因组分析揭示了 Q29 噬菌体的功能基因和系统发育进化。我们的研究结果表明，奇异变形杆菌噬菌体 Q29 具有一个直径为 95nm 的二十面体对称头部和一个长 240nm 的尾部。此外，噬菌体 Q29 在 37℃至 55℃的温度范围内和 pH 值为 4 至 9 的条件下表现出稳定性。该噬菌体的最佳感染复数（MOI）被确定为 0.001。此外，一步生长曲线结果表明潜伏期约为 15 分钟，爆发期约为 35 分钟，每个细胞的平均裂解量约为 60 个噬菌斑形成单位（PFU）。噬菌体 Q29 的基因组全长为 58664 个碱基，编码 335 个开放阅读框（ORFs），不携带任何抗生素抗性基因。此外，遗传进化分析将噬菌体 Q29 归类为尾噬菌体科和肌尾噬菌体属。本研究为进一步开发奇异变形杆菌噬菌体生物制剂提供了有价值的研究材料，特别是考虑到这种细菌对抗生素耐药性的日益挑战，噬菌体生物制剂作为抗生素的替代品具有广阔的前景。
