Lytic Bacteriophages against Mutidrug-Resistant Klebsiella pneumoniae: Development of an Effective Phage-based Approach to Combat Multidrug Resistance

Abstract This study aimed to develop a phage-based approach against Klebsiella pneumoniae sequence type (ST16). Phages were investigated using sewage samples from Brazil, Bangladesh, Saudi Arabia, Thailand and the United Kingdom. After isolation, the bacteriophages were submitted to microbiological, structural and genomic characterisation. The best phages were selected to integrate a phage-cocktail for potential use in humans. In vitro and in vivo experiments were performed to demonstrate the efficiency of this approach using a collection of 56 clinical strains of K. pneumoniae ST16 with distinct genetic backgrounds. Anti-biofilm activity, synergism with meropenem and activity in human body fluids were also evaluated. Fourteen lytic phages were isolated, belonging to Autographiviridae, Ackermannviridae, Demerecviridae, Drexlerviridae, and Myoviridae families. The viruses demonstrated good activity against our collection of K. pneumoniae ST16 at a different range of temperatures but also against other important Klebsiella clones such as ST11, ST15, and ST258. The cocktail Katrice-16 was highly active in vitro against K. pneumoniae ST16 collection consisting of isolates from several disparate countries. It demonstrated good in vivo activity in the Galleria mellonella model, anti-biofilm and synergic activity with meropenem. In addition, we also showed the Katrice-16 activity in human body fluids. Our results reinforce how effective bacteriophages can be, supporting their capacity for human clinical use to combat prevalent antimicrobial resistance bacterial clones.