Bacillus-infecting bacteriophage Izhevsk harbors thermostable endolysin with broad range specificity

Several bacterial species belonging to the Bacillus cereus group are known to be causative agents of food poisoning and severe human diseases. Bacteriophages and their lytic enzymes called endolysins have been widely shown to provide for a supplemental or primary means of treating bacterial infections. In this work we present a new broad-host-range phage Izhevsk, which infects the members of the Bacillus cereus group. Transmission electron microscopy, genome sequencing and comparative analyses revealed that Izhevsk is a temperate phage with Siphoviridae morphology and belongs to the same genus as the previously described but taxonomically unclassified bacteriophages Tsamsa and Diildio. The Ply57 endolysin of Izhevsk phage has broad-spectrum activity against B. cereus sensu lato. The thermolability of Ply57 is higher than that of the PlyG of Wβ phage. This work contributes to our current understanding of phage biodiversity and may be useful for further development of efficient antimicrobials aimed at diagnosing and treating infectious diseases and food contaminations caused by the Bacillus cereus group of bacteria.