Phage therapy has recently been revitalized in the West with many successful applications against multi-drug-resistant bacterial infections. However, the lack of geographically diverse bacteriophage (phage) genomes has constrained our understanding of phage diversity and its genetics underpinning host specificity, lytic capability, and phage-bacteria co-evolution. This study aims to locally isolate virulent phages against uropathogenic Escherichia coli (E. coli) and study its phenotypic and genomic features. Three obligately virulent Escherichia phages (øEc_Makalu_001, øEc_Makalu_002, and øEc_Makalu_003) that could infect uropathogenic E. coli were isolated and characterized. All three phages belonged to Krischvirus genus. One-step growth curve showed that the latent period of the phages ranged from 15 to 20 min, the outbreak period ~ 50 min, and the burst size ranged between 74 and 127 PFU/bacterium. Moreover, the phages could tolerate a pH range of 6 to 9 and a temperature range of 25–37 °C for up to 180 min without significant loss of phage viability. All phages showed a broad host spectrum and could lyse up to 30% of the 35 tested E. coli isolates. Genomes of all phages were approximately ~ 163 kb with a gene density of 1.73 gene/kbp and an average gene length of ~ 951 bp. The coding density in all phages was approximately 95%. Putative lysin, holin, endolysin, and spanin genes were found in the genomes of all three phages. All phages were strictly virulent with functional lysis modules and lacked any known virulence or toxin genes and antimicrobial resistance genes. Pre-clinical experimental and genomic analysis suggest these phages may be suitable candidates for therapeutic applications.

噬菌体疗法最近在西方重新焕发活力，在对抗多重耐药细菌感染方面取得了许多成功的应用。然而，缺乏地理上多样化的噬菌体基因组限制了我们对噬菌体多样性及其支持宿主特异性、裂解能力和噬菌体-细菌共同进化的遗传学的理解。本研究旨在局部分离针对尿路致病性大肠杆菌（E. coli）的强毒噬菌体，并研究其表型和基因组特征。分离并鉴定了三种可感染尿路致病性大肠杆菌的专性毒力埃希氏菌噬菌体（øEc_Makalu_001、øEc_Makalu_002 和 øEc_Makalu_003）。所有三种噬菌体均属于Krischvirus属。一步生长曲线显示，噬菌体的潜伏期为15至20分钟，爆发期为50分钟左右，爆发大小为74至127 PFU/细菌。此外，噬菌体可以耐受 6 至 9 的 pH 范围和 25-37 °C 的温度范围长达 180 分钟，而不会显着丧失噬菌体活力。所有噬菌体均表现出广泛的宿主谱，并且可以裂解 35 种测试的大肠杆菌分离株中高达 30% 的细菌。所有噬菌体的基因组约为 163 kb，基因密度为 1.73 个基因/kbp，平均基因长度为 951 bp。所有噬菌体的编码密度约为 95%。在所有三种噬菌体的基因组中都发现了假定的溶素、穴蛋白、内溶素和跨蛋白基因。所有噬菌体均具有严格的毒力，具有功能性裂解模块，并且缺乏任何已知的毒力或毒素基因以及抗菌素耐药性基因。临床前实验和基因组分析表明这些噬菌体可能是治疗应用的合适候选者。