Isolation and Characterization of Phage ZXL-01 and Preliminary Investigation of Its Therapeutic Effect on Periapical Periodontitis.

() is a major pathogen responsible for refractory apical periodontitis (RAP). It can penetrate deep into dentinal tubules, form persistent biofilms, and exhibit antibiotic resistance, thereby limiting the efficacy of conventional antimicrobial treatments. Bacteriophages (phages), due to their strong lytic activity and host specificity, have emerged as promising alternatives. In this study, a novel strictly lytic phage, ZXL-01, was isolated from lake water in Jilin, China. ZXL-01 demonstrated remarkable stability under extreme conditions, including thermal tolerance at 60 °C for 1 h and a wide pH range (4-11). Whole-genome sequencing (GenBank accession number: ON113334) revealed a genome of 40,804 bp with no virulence or tRNA genes, confirming its identity as an phage. Importantly, ZXL-01 exhibited potent antibiofilm activity, reducing biofilm biomass by approximately 69.4% in the inhibition group and 68.4% in the lysis group (both < 0.001). In an in vitro root canal infection model induced by , scanning electron microscope (SEM) observations confirmed that ZXL-01 effectively inhibited biofilm formation and disrupted mature biofilms. These findings highlight the potential of ZXL-01 as a novel antimicrobial agent for the treatment of -associated apical periodontitis.