Expression and application of a novel Holin Hol6A3 in phage PD6A3 of Acinetobacter baumannii

The current overuse of antibiotics presents significant challenges in treating drug-resistant bacterial infections. Bacteriophages have recently emerged as potential alternatives to antibiotics. Nevertheless, their high specificity and narrow host range limit their clinical application. The entire genome of phage PD6A3 was sequenced. Bioinformatic tools were employed to predict genes and determine protein structures. A prokaryotic expression system for Hol6A3 was established. The antibacterial efficacy, thermal and pH stability, and cytotoxicity of Hol6A3 were thoroughly investigated. Additionally, the in vitro antibacterial application of Holin was also studied. This study achieved high-purity expression of Hol6A3, with a purity of 1.47 mg/ml. Biochemical properties revealed that Hol6A3 retained stable activity under various conditions. Hol6A3 exhibited broad-spectrum and potent bactericidal effects against various pathogens and synergistic effects in combating bacterial infections with endolysin Ply6A3. Hol6A3 possesses considerable antibacterial potential, capable of degrading a broad spectrum of bacteria, demonstrating robust stability and a low propensity for the development of drug resistance. Consequently, Hol6A3 may emerge as a promising alternative to traditional antibiotics.