Phage vB_AbaM_MU1 for biocontrol of carbapenem-resistant Acinetobacter baumannii (CRAB) isolated from wound infection

Abstract Background Carbapenem-resistant Acinetobacter baumannii (CRAB) continues to pose significant public health in clinical settings due to its remarkable genomic plasticity and resistance to available therapeutic drugs, including carbapenems. Bacteriophage has emerged as an optimistic solution capable of addressing such drug resistance dilemma. This study represents a comprehensive characterization of a novel Acinetobacter phage with potential application against CRAB-associated wound infections. Methods Sewage sample was obtained, processed, and enriched with A. baumannii M13 phage(s) for the purpose of phages’ isolation. The isolated phage was examined using transmission electron microscope (TEM) and identified in terms of host range and efficiency of plating through spot test and plaque assay, respectively. Phage stability was screened following thermal, pH and ethanol assays. Replication kinetics were investigated through adsorption and single step growth curve. Furthermore, the in-vitro antibacterial potential was verified through measuring the optical density of the treated M13 culture at different Multiplicity of infections (MOIs) over 6 h shaking incubation. This is in tandem with preliminary screening of the vB_AbaM_MU1 safety through genomic and phylogenetic analysis of the isolated phage. Results A novel lytic Acinetobacter phage vB_AbaM_MU1 was isolated and categorized as T4-like Myovirus with genomic size 167.200 bp, which was classified into the family Straboviridae in class Caudoviricetes , based on morphological and genomic analyses. It showed lytic efficiency against 9/17 CRAB strains. Infectivity and structural integrity revealed thermal stability up to 60℃, pH tolerance within pH range (3–11), sensitivity to different EtOH concentrations (10%, 50%, 75%, and 95%). In addition, vB_AbaM_MU1 displayed distinctive infection kinetics with 6 min adsorption, short latent (over 30 min), and high bursting (326 PFU/infected cell). The in-vitro bacteriolytic infectivity revealed robust and steady antibacterial action at MOI of 1 and above. Conclusion These findings provide a strong, well-justified foundation for considering vB_AbaM_MU1 phage as successful candidate for phage therapy in treating CRAB- induced wound infections.