Isolation and characterization of a rare waterborne lytic phage of Salmonella enterica serovar Paratyphi B.

A lytic phage of Salmonella serovar Paratyphi B, named φSPB, was isolated from surface waters of the Pavana River in India. Phage φSPB is a member of the Podoviridae family and is morphologically similar to the 7-11 phages of the C3 morphotype of tailed phages, characterized by a very long, cigar-shaped head. The head measured approximately 153 × 57 nm, and the tail size was 12 × 7 nm. The phage was stable over a wide range of pH (4-9) and temperature (4-40 °C). The adsorption rate constant was 4.7 × 10(-10). Latent and eclipse periods were 10 and 15 min, respectively, and the burst size was 100 plaque-forming units/infected cell after 25 min at 37 °C. The phage DNA was 59 kb in size. Ten major proteins were observed on SDS-PAGE, although some of these proteins could be bacterial contaminants. This is the first report of Salmonella enterica subsp. enterica serovar Paratyphi B phage of C3 morphotype from India that has many unique features, such as high replication potential, short replication time, and stability over a wide range of pH and temperature, making it a promising biocontrol agent against the drug-resistant strains of Salmonella Paratyphi B.