Characterization and Genomic Analysis of Novel Bacteriophage ΦCS01 Targeting Cronobacter sakazakii.

Abstract

Cronobacter sakazakii is an opportunistic pathogen causing serious infections in neonates. In this study, a bacteriophage ΦCS01, which infects C. sakazakii, was isolated from swine feces and its morphology, growth parameters, and genomic analysis were investigated. Transmission electron microscopy revealed that ΦCS01 has a spherical head and is 65.74 nm in diameter with a 98.75 nm contracted tail, suggesting that it belongs to the family Myoviridae. The major viral proteins are approximately 71 kDa and 64 kDa in size. The latent period of ΦCS01 was shown to be 60 min, and the burst size was 90.7 pfu (plaque-forming units)/ infected cell. Bacteriophage ΦCS01was stable at 4-60°C for 1 h and lost infectivity after 1 h of heating at 70°C. Infectivity remained unaffected at pH 4-9 for 2 h, while the bacteriophage was inactivated at pH <3 or >10. The double-stranded ΦCS01 DNA genome consists of 48,195 base pairs, with 75 predicted open reading frames. Phylogenetic analysis is closely related to that of the previously reported C. sakazakii phage ESP2949-1. The newly isolated ΦCS01 shows infectivity in the host bacterium C. sakazakii, indicating that it may be a promising alternative to antibacterial agents for the removal of C. sakazakii from powdered infant formulas.