Acinetobacter baumannii is emerging as a challenging nosocomial pathogen due to its rapid evolution of antibiotic resistance. We report characterization of two novel bacteriophages, PBAB08 and PBAB25, infecting clinically isolated, multidrug-resistant (MDR) A. baumannii strains. Both phages belonged to Myoviridae of Caudovirales as their morphology observed under an electron microscope. Their genomes were double stranded linear DNAs of 42,312 base pairs and 40,260 base pairs, respectively. The two phages were distinct from known Acinetobacter phages when whole genome sequences were compared. PBAB08 showed a 99% similarity with 57% sequence coverage to phage AB1 and PBAB25 showed a 97% similarity with 78% sequence coverage to phage IME_AB3. BLASTN significant alignment coverage of all other known phages were <30%. seventy six and genes encoding putative phage proteins were found in the genomes of pbab08 pbab25, respectively. their genomic organizations sequence similarities consistent with modular theory evolution. therapeutic efficacy a cocktail containing two other phages evaluated mice model nasal infection mdr a. baumannii. treated showed 2.3-fold higher survival rate than those untreated 7 days post infection. addition, 1/100 reduction number baumannii lung was observed. also, inflammatory responses which injected by intraperitoneal, intranasal, or oral route investigated. increase serum cytokine minimal regardless injection route. 20% ige production seen intraperitoneal route, but not routes. thus, newly isolated could serve as potential candidate for interventions to treat baummannii infections.
Journal: Frontiers in microbiology
DOI: 10.3389/fmicb.2018.00696
Year: 2018