Genomic characterization of Pseudomonas aeruginosa infecting Abidjanvirus Lucjan.

Multidrug-resistant (MDR) Pseudomonas aeruginosa remains a major cause of hospital-acquired infections, and alternative antimicrobial strategies are urgently needed. Bacteriophages infecting P. aeruginosa are increasingly explored as adjuncts or alternatives to antibiotic therapy, yet many newly isolated phages remain incompletely characterized. Here, we report the genomic and functional characterization of bacteriophage Lucjan, a lytic virus infecting clinical isolates of P. aeruginosa. Whole-genome sequencing revealed a 59,433 bp double-stranded DNA genome with 63.7% GC content encoding 81 predicted open reading frames. Comparative genomics and VIRIDIC analysis established Lucjan as a novel species within the genus Abidjanvirus. No antibiotic resistance genes, virulence factors, or canonical lysogeny-associated modules were detected. Lifestyle prediction and genomic architecture, including a canonical holin-endolysin cassette, support a lytic infection strategy. Biological characterization demonstrated adsorption to host cells, a latent period of approximately 60 min, and a burst size of 82 ± 14 PFU per infected cell. Lucjan infected 42% of tested clinical isolates and significantly reduced established P. aeruginosa biofilms in vitro. Combined treatment with selected antibiotics resulted in enhanced suppression of bacterial growth compared with single-agent exposure. Together, these findings position Lucjan as a genomically safe and functionally active representative of the Abidjanvirus lineage and highlight the potential of environmentally derived lytic phages as candidates for further evaluation in combinatorial antimicrobial strategies.