Characterization and Complete Genomic Analysis of Vibrio Parahaemolyticus-Infecting Phage KIT05

Isolation and characterization of a novel bacteriophage against Vibrio alginolyticus from coastal waters and its environmental tolerance

In response to the problems associated with drug resistance resulting from the use of antibiotics, phages have become desirable options for the treatment of Vibrio alginolyticus disease in aquaculture. In this study, we isolated a novel double-stranded DNA (dsDNA) phage named vB_ValC_WD615 infecting V. alginolyticus; this phage belongs to the family Podoviridae and has a short noncontractile tail (13 ± 1.5 nm) and an icosahedral head (60.2 ± 2 nm); its genome is 50,522 bp and encodes 69 open reading frames (ORFs) and no lysogenic genes were annotated in the genome. Physiological results indicate that vB_ValC_WD615 infects V. alginolyticus SC1 with a burst size of 335 PFU/cell and can maintain stable infectivity within temperature and pH conditions ranging from 4 to 45 °C and 3 to 11, respectively. The results suggest that the vB_ValC_WD615 isolated from coastal waters could be a potential candidate for phage therapy targeting V. alginolyticus.

Characterization and genomic analysis of a broad-spectrum lytic phage PG288: A potential natural therapy candidate for Vibrio infections

Vibrio parahaemolyticus, an important zoonotic pathogen, can cause severe diseases and even death in aquatic animals and humans. As the widespread use of antibiotics gradually diminishes their effectiveness, phages, which can selectively lyse bacteria, are garnering increased attention as a valuable alternative antibacterial strategy. This study characterized PG288, a lytic phage utilizing V. parahaemolyticus strain G855 as its host. Morphologically, the phage features a polyhedral head and a long, non-retractable tail. Bactericidal assays revealed that phage PG288 exhibited a strong lytic ability against V. parahaemolyticus strain G855 and demonstrated a broad host range, as evidenced by the ability to infect several distinct Vibrio species. The one-step growth curve indicated a latent period of approximately 50 min for phage PG288, with a burst size of roughly 92 PFU per cell. Additionally, phage PG288 exhibited remarkable stability within a temperature range of 20-50°C and a pH range of 4-10. Genomic analysis unveiled 105 ORFs within phage PG288, notably devoid of genes associated with antibiotic resistance, virulence, and lysogenic activity. Phylogenetic analysis conclusively identified it as a new member of the genus Mardecavirus within the class Caudoviricetes. In summary, this study contributes valuable insights to the phage database, presenting phage PG288 as a promising candidate for phage therapies against Vibrio infections.

Vibrio-infecting bacteriophages and their potential to control biofilm

The emergence and spread of antibiotic-resistant pathogenic bacteria have necessitated finding new control alternatives. Under these circumstances, lytic bacteriophages offer a viable and promising option. This review focuses on Vibrio-infecting bacteriophages and the characteristics that make them suitable for application in the food and aquaculture industries. Bacteria, particularly Vibrio spp., can produce biofilms under stress conditions. Therefore, this review summarizes several anti-biofilm mechanisms that phages have, such as stimulating the host bacteria to produce biofilm-degrading enzymes, utilizing tail depolymerases, and penetrating matured biofilms through water channels. Additionally, the advantages of bacteriophages over antibiotics, such as a lower probability of developing resistance and the ability to infect dormant cells, are discussed. Finally, this review presents future research prospects related to further utilization of phages in diverse fields.

Genetic engineering of bacteriophages: Key concepts, strategies, and applications

Bacteriophages are the most abundant biological entity in the world and hold a tremendous amount of unexplored genetic information. Since their discovery, phages have drawn a great deal of attention from researchers despite their small size. The development of advanced strategies to modify their genomes and produce engineered phages with desired traits has opened new avenues for their applications. This review presents advanced strategies for developing engineered phages and their potential antibacterial applications in phage therapy, disruption of biofilm, delivery of antimicrobials, use of endolysin as an antibacterial agent, and altering the phage host range. Similarly, engineered phages find applications in eukaryotes as a shuttle for delivering genes and drugs to the targeted cells, and are used in the development of vaccines and facilitating tissue engineering. The use of phage display-based specific peptides for vaccine development, diagnostic tools, and targeted drug delivery is also discussed in this review. The engineered phage-mediated industrial food processing and biocontrol, advanced wastewater treatment, phage-based nano-medicines, and their use as a bio-recognition element for the detection of bacterial pathogens are also part of this review. The genetic engineering approaches hold great potential to accelerate translational phages and research. Overall, this review provides a deep understanding of the ingenious knowledge of phage engineering to move them beyond their innate ability for potential applications.