Isolation and characterization of novel phage (Podoviridae φParuNE1) and its efficacy against multi-drug-resistant Pseudomonas aeruginosa planktonic cells and biofilm

Background Bacterial pathogen (Pseudomonas aeruginosa) could form biofilm that conveys multi-drug resistance. Bacteriophage as an alternative to antibacterial resistance is useful against biofilm complications. This study evaluated antibacterial and biofilm removal activities of lytic phage, specific against multi-drug-resistant clinical P. aeruginosa. Results The phage showed a wide range of pH (5-10) and heat (7-44 degrees C) stability. Electron microscopy showed phi PauNE1 phage head (60 nm in diameter) and non-contractile tail (12 nm in length by 8 nm in width); hence, the family Podoviridae and the order Caudovirales. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed structured protein of 55 kDa and double-stranded DNA of 45 kb. The phage was species specific and had broad host range activity. It inhibited bacterial growth at multiplicity of infection (MOI) 1-0.000001 pfu/ml. Inhibition was maximal at both low (1 x 10(5)) and high (1 x 10(9)) bacterial CFU/ml. Biofilm removal test showed that the phage removed more than 60% cell biomass within CFU/ml of 1.5 x 10(8), 6.0 x 10(8) and l.0 x 10(9). Conclusion Phage (phi PauNE1) was unique and had broad host range activity. The phage exhibited strong bacteriolytic activity against biofilm forming multi-drug-resistant strains. It had no lytic effect on the heterogeneous strains and so a promising bioagent.