Isolation, characterization and genomic analysis of a novel lytic bacteriophage vB_SsoS-ISF002 infecting Shigella sonnei and Shigella flexneri.

Purpose: Shigellosis is one of the most important food-borne and water-borne diseases worldwide. Although antibiotics are considered as efficient agents for shigellosis treatment, improper use of these has led to the emergence of antibiotic-resistant Shigella spp. Therefore, finding a new strategy as alternative treatment seems necessary.
Methodology: Different samples from a wastewater treatment plant were used to isolate Shigella spp. specific phages. Physiological properties were determined, and genomic analysis was also carried out.
Results: A virulent Siphoviridae bacteriophage, vB_SsoS-ISF002, was isolated from urban wastewater in Iran and showed infectivity to different isolates of both Shigella sonnei and Shigella flexneri. vB_SsoS-ISF002 was stable at different pH values and temperatures. It had a short latent period (15 min), a large burst size (76±9 p.f.u. cell ^-1 ) and appropriate lytic activity especially at high MOI. Its genome (dsDNA) was 50 564 bp with 45.53 % GC content and 76 predicted open reading frames. According to comparative genomic analysis and phylogenic tree construction, vB_SsoS-ISF002 was considered as a member of the T1virus genus.
Conclusion: These results indicated that vB_SsoS-ISF002 is a novel virulent T1virus phage and may have potential as an alternative treatment for shigellosis.