Isolation and characterization of a novel lytic bacteriophage for Faecalibacterium prausnitzii, a key member of the human gut microbiota.

Faecalibacterium prausnitzii is a dominant and health-associated member of the human gastrointestinal tract that is consistently depleted in individuals with metabolic, cardiovascular, and psychiatric disorders. Despite its importance in gut health, little is known about the bacteriophages (or phages) that infect this species. Phages are increasingly recognized as key regulators of bacterial population dynamics in the gut microbiota; however, while prophages of F. prausnitzii have been described, no lytic phages targeting this bacterium have been reported. Here, we describe the isolation and characterization of the first lytic F. prausnitzii bacteriophage, vB_Fpr_FP01. Whole-genome sequencing and comparative genomics analysis demonstrate that FP01 represents a novel species, clustering within a genus that includes an uncharacterized phage within the class Caudovirales. Comparative analysis also identified closely related viral sequences in the human gut virome dataset, suggesting that related phages occur in gut-associated environments. These findings expand the current knowledge of F. prausnitzii-associated phages and provide a framework for future studies investigating phage‒host interactions and their role in shaping gut microbial communities.