Isolation and characterization of a novel phage AbT1 and evaluating its anti-biofilm activity and antibiotic synergy

Acinetobacter baumannii is a formidable multidrug-resistant pathogen prevalent in healthcare settings. Amid the escalating challenge of antimicrobial resistance, phage therapy has regained significant attention. This approach harnesses the natural predatory ability of bacteriophages to combat bacterial infections.

A novel phage, AbT1, specific for A. baumannii, was isolated and comprehensively characterized. Under testing conditions, the phage AbT1 demonstrated notable stability across a broad spectrum of temperatures and pH conditions, and suggested potent lytic activity against A. baumannii isolates. Phage AbT1 belongs to the class Caudoviricetes. It appears phylogenetically closest to members of the genus Vieuvirus and likely represents a novel species. It possesses a double-stranded DNA genome of 53,410 bp containing 78 open reading frames (ORFs), among which 29 are predicted to encode structural or functional proteins. Furthermore, treatment with phage AbT1 mitigated A. baumannii-induced cytotoxicity in host cells and disrupted biofilm formation. Notably, the combination of phage AbT1 with antibiotics (GM/Kan) significantly enhanced bactericidal efficacy and improved the survival rate of Galleria mellonella larvae, compared to either monotherapy alone.

This study highlights the substantial therapeutic potential of phage AbT1, whether used alone or in combination with antibiotics, providing valuable insights for the development of phage-based approaches to combat multidrug-resistant A. baumannii infections.