Bacteriophage treatment of burn wound infection caused by Pseudomonas aeruginosa PAO in BALB/c mice

Therapeutic potential of five purified and well characterized bacteriophages (Pa29, Pa30, Pa31, Pa33 and Pa34) was evaluated in thermally injured and Pseudomonas aeruginosa PAO infected mice. Efficacy of five P. aeruginosa phages was assessed on the basis of percentage survival of phage treated mice. Toxicity evaluation of all the phages, showed them to be non toxic as no sign of morbidity and mortality was observed in phage treated mice. Survival and stability of Pseudomonas specific phages was evaluated in mice and maximum phage count in various organs was obtained at 3 h which persisted till 24 h and no phage could be detected at 36 h post inoculation. The results of the study indicate that a single dose of phages intraperitoneally (i.p.) at highest multiplicity of infection (MOI) of 900, did not provide any protection from P. aeruginosa PAO induced burn wound infection in mice. Since a single application of Pseudomonas specific phages did not restrict the infection in thermally injured mice by P. aeruginosa PAO, the experiment was repeated by administering these phages at 24 h intervals, starting immediately after the infection up to 72 h at above mentioned MOI, even then no protection was observed in phage treated groups and results were comparable to control groups with 100 % mortality (P>0.05). The results of the present study show that, phages belonging to Podoviridae family, order Caudovirales were not effective in protecting P. aeruginos