Bacteriophage therapy of a Vibrio parahaemolyticus infection caused by a multiple-antibiotic-resistant O3:K6 pandemic clinical strain.

BACKGROUND Recently isolated Vibrio parahaemolyticus strains have displayed multiple antibiotic resistance. Alternatives to conventional antibiotics are needed, especially for the multiple-antibiotic-resistant V. parahaemolyticus pandemic strain. METHODS A bacteriophage, designated pVp-1, showed effective infectivity for multiple-antibiotic-resistant V. parahaemolyticus and V. vulnificus, including V. parahaemolyticus pandemic strains. The therapeutic potential of the phage was studied in a mouse model of experimental infection using a multiple-antibiotic-resistant V. parahaemolyticus pandemic strain. We monitored the survivability and histopathological changes, quantified the bacterial and phage titers during phage therapy, and observed the immune response induced by phage induction. RESULTS Phage-treated mice displayed protection from a V. parahaemolyticus infection and survived lethal oral and intraperitoneal bacterial challenges. CONCLUSIONS To the best of our knowledge, this is the first report of phage therapy in a mouse model against a multiple-antibiotic–resistant V. parahaemolyticus pandemic strain infection.