The phage P.E1 isolated from hospital sewage reduces the growth of Escherichia coli

This study involves partial characterisation of a lytic bacteriophage P.E₁ against a multi drug-resistant clinical isolate of Escherichia coli, isolated from hospital sewage supply. The phage P.E₁ has showed a narrow host range suitable for its use in phage therapy. Phage showed lytic activity up to 70°C and at alkaline conditions, but at higher acidic conditions its activity decreased. Latent period and burst size of P.E₁ estimated from single-step growth curve was 40 min and 185 plaque-forming units per cell, respectively. The phage P.E₁ reduced the growth of host bacteria during the initial 12?h of infection; however, the host bacteria developed resistance afterwards. During the 24-hour observation period, the bacteriophage could still reduce the growth of its host bacteria evident by lower optical density in the phage-treated samples compared with control. The phage genome was double-stranded DNA and larger than 12?kb in size. Further manipulations of genome and proteins may help to unveil the unique aspects of this phage, to use it in phage therapy against E. coli.