Lytic potential of a filamentous bacteriophage isolated from sewage water in Tehran on clinical carbapenem-resistant strains

Acinetobacter baumannii (A. baumannii), an opportunistic pathogen, has been isolated from sewage, soil, and hospital wards. The prevalence of multidrug-resistance A. baumannii has seriously caused a health crisis in hospital settings. Bacteriophages have been used as an alternative therapy for control carbapenem-resistant bacteria-caused infections. We aimed to assay lytic effect of a filamentous phage on clinical bacterial strains.

500-ml water samples was collected from sewage in Tehran. Sewage samples were precipitated at 6000 rpm for 10 minutes and filtered using 0.45-µm syringe filters. Bacteriophage was isolated using double-layer agar assay and evaluated its stability at various pH and temperature ranges. In addition, the stability of the phage was assayed at chloroform 0.1%.

Transmission electron microscopy imagine showed phage is filamentous called vB-AbaI-TMU2. The phage affected on its own host so that could not effect on any Pseudomonas aeruginosa and Klebsiella pneumoniae strains. vB-AbaI-TMU2 phage was stable at pH 5 and 7 and also temperatures 25 and 37°C. vB-AbaI-TMU2 was stable at chloroform 0.1%. vB-AbaI-TMU2 phage infected carbapenem-resistant A. baumannii strains while other bacterial strains were resistant to.

The present study indicated the isolated phage had a narrow host range and is susceptible to various pH values and temperatures.