Vibrio vulnificus Bacteriophage SSP002 as a Possible Biocontrol Agent

Abstract

ABSTRACTA novelVibrio vulnificus-infecting bacteriophage, SSP002, belonging to theSiphoviridaefamily, was isolated from the coastal area of the Yellow Sea of South Korea. Host range analysis revealed that the growth inhibition of phage SSP002 is relatively specific toV. vulnificusstrains from both clinical and environmental samples. In addition, a one-step growth curve analysis and a bacteriophage stability test revealed a latent period of 65 min, a burst size of 23 ± 2 PFU, as well as broad temperature (20°C to 60°C) and pH stability (pH 3 to 12) ranges. A Tn5random transposon mutation ofV. vulnificusand partial DNA sequencing of the inserted Tn5regions revealed that theflhA,flhB,fliF, andfleQmutants are resistant to SSP002 phage infection, suggesting that the flagellum may be the host receptor for infection. The subsequent construction of specific gene-inactivated mutants (flhA,flhB,fliF, andfleQ) and complementation experiments substantiated this. Previously, the genome of phage SSP002 was completely sequenced and analyzed. Comparative genomic analysis of phage SSP002 andVibrio parahaemolyticusphage vB_VpaS_MAR10 showed differences among their tail-related genes, supporting different host ranges at the species level, even though their genome sequences are highly similar. An additional mouse survival test showed that the administration of phage SSP002 at a multiplicity of infection of 1,000 significantly protects mice from infection byV. vulnificusfor up to 2 months, suggesting that this phage may be a good candidate for the development of biocontrol agents againstV. vulnificusinfection.