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Bacteriophages, viruses that infect and replicate within prokaryotic cells are the most abundant life forms in the environment, yet the vast majority of them have not been properly reported or even discovered. Almost all reported bacteriophages infecting the Enterobacteriaceae family, with Escherichia coli being the major subject of studies, have been isolated from wastewater, sewage, and effluent resources. In the present study, we focused on the distribution and biodiversity of Shigella phages in an aquatic ecosystem. While no Shigella bacteria was recovered from the Yangtze River, three lytic phages were isolated from this ecosystem and were subjected to biological, morphological, and genomic characteristics. Comparative genomics and phylogenetic analyses demonstrated that vB _SflM_004 isolate belongs to Myoviridae family, Felixounavirus genus of Ounavirinae subfamily, vB_SdyM_006 was classified under the same family, however, it is suggested to be in a new genus under Tevenvirinae subfamily with some other related bacteriophages. vB_SsoS_008 phage belongs to the Siphoviridae family, Tunavirus genus, Tunavirinae subfamily. The phages did not harbor any genes involved in the lysogenic cycles and showed a high temperature and pH stability. The biodiversity of the isolated phages highly suggests that continued isolation on non-model members of Enterobacteriaceae family is necessary to fully understand bacteriophage diversity in aquatic environments. [ABSTRACT FROM AUTHOR]

Shigella dysenteriae is one of the members of Shigella genus which was the main responsible of different Shigellosis outbreaks worldwide. The increasing consumption of antibiotics has led to the emergence and spreading of antibiotic-resistant strains. Therefore, finding new alternatives for infection control is essential, one of which is using bacteriophages. Lytic bacteriophage against Shigella dysenteriae was isolated from petroleum refinery wastewater. Phage morphological and genetic characteristics were studied using TEM, and sequencing, respectively. In addition, the genome size was estimated, and phage resistance to different temperatures and pH, host range, adsorption rate, and one-step growth were investigated. According to the morphology and genetic results, this phage was named vB-SdyS-ISF003. Sequencing of the PCR products revealed that the vB-SdyS-ISF003 phage belongs to the species T1virus , subfamily Tunavirinae of family Siphoviridae. This was the first detected bacteriophage against S. dysenteriae , which belongs to the family Siphoviridae. In addition, its host range was limited to S. dysenteriae. The genome size was about 62 kb. vB-SdyS-ISF003 phage has a number of desirable characteristics including the limited host range to S. dysenteriae , very short connection time, a relatively wide range of temperature tolerance −20 to 50 °C, pH tolerance of 7–9 without significant reduction in the phage titer. vB-SdyS-ISF003 is a novel virulent T1virus phage and has the appropriate potential for being used in bio controlling of S. dysenteriae in different condition. • vB-SdyS-ISF003 is a novel lytic bacteriophage belongs to Siphoviridae infecting S. dysenteriae. • Sequencing of the PCR amplicons demonstrates that vB-SdyS-ISF003 phage belongs to the genus T1virus • Genome length of vB-SdyS-ISF003 is about 62000 bp. • Phage vB-SdyS-ISF003 can be introduced as a promising antibacterial agent for S. dysenteriae treatment. [ABSTRACT FROM AUTHOR]

Shigella, the globally distributed causative agent of bacillary dysentery, is an important microbial contamination in raw and ready-to-eat foods. The recent commercial use of phage cocktails in the food industry is evidence that the method is a highly effective solution in controlling the pathogenic bacteria, especially the antibiotic-resistant strains. This research addresses the effects of a novel phage cocktail made of six different lytic bacteriophages to prevent drug resistant isolates of Shigella species in a wide variety of food products with a different matrix structure, viscosity, carbon content, and texture properties including cooked chicken, cherry tomato, yoghurt, cucumber and Chinese cabbage. After seven days of treatment with the phage cocktail, more than 99% of the bacterial count decreased compared to the control sample (P < 0.0001). The cocktail stability in dry conditions showed that the bacteriophages remain desirably active during food products' average shelf life. The prepared phage cocktail showed to be a very effective product for bio-controlling Shigella due to its high overlap of the host spectrums, the potential for use in a variety of foods, and stability in dry conditions. • The phages used for preparing the phage cocktail had high efficiency of plating. • Almost all isolated were infected by at least one of the phages. • Three quarters of the isolates were lysed by at least to 2 or more phages. • The phage cocktail maintained on the optimal performance at dry condition. • The cocktail reduced remarkably (99%) Shigella in different food samples. [ABSTRACT FROM AUTHOR]