Isolation, characterization, and genomic analysis of BUCT627: a lytic bacteriophage targeting Stenotrophomonas maltophilia.

Stenotrophomonas infections pose significant therapeutic challenges due to escalating resistance to antibiotics and chemotherapeutic agents. Phages offer a potential solution by virtue of their specific bacterial targeting capabilities. In this study, we isolated a new Stenotrophomonas bacteriophage, named BUCT627, from hospital sewage. Phage BUCT627 exhibited a 30-min latent period and demonstrated a burst size of 46 plaque forming unit (PFU)/cell. Remarkably, this phage displayed robust stability across a wide pH range (pH 3-13) and exhibited resilience under varying thermal conditions. The receptor of phage BUCT627 on Stenotrophomonas maltophilia No. 826 predominantly consist of surface proteins. The complete genome of phage BUCT627 is a 61 860-bp linear double-stranded DNA molecule with a GC content of 56.3%, and contained 99 open reading frames and two tRNAs. Notably, no antibiotic resistance, toxin, virulence-related genes, or lysogen-formation gene clusters was identified in BUCT627. Transmission electron microscopy and phylogeny analysis indicated that this phage was a new member within the Siphoviridae family. The results of this study will enhance our understanding of phage diversity and hold promise for the development of alternative therapeutic strategies against S. maltophilia infections.