Identification of Flavobacterium psychrophilum Vaccine Candidates Using Comparative Genomics and Reverse Vaccinology
The Gram-negative bacterium Flavobacterium psychrophilum is the etiological agent of Bacterial Cold Water Disease and Rainbow Trout Fry Syndrome in salmonid fishes, diseases that cause significant losses in the aquaculture industry. No effective vaccines are available and antimicrobials used to control this pathogen are becoming increasingly less effective due to increasing rates of antimicrobial resistance. To gain a better understanding of the pathogenesis of F. psychrophilum, the genomes of 4 highly virulent and 2 less virulent strains were studied. Comparative genomics analysis revealed that the pan-genome of these 6 strains contains 3,040 genes; the core genome of virulent strains 2,228 genes and that of the less virulent strains 2,060 genes. No novel virulence factors were identified, but evidence was found that "antivirulence" genes could play a role in pathogenesis. As well, three promising candidates were identified using a reverse vaccinology approach.