Characterization of broad host range bacteriophages vKpIN31 and vKpIN32, with anti-biofilm potential against Hospital acquired multidrug-resistant Klebsiella pneumoniae in Dakar, Senegal.
Klebsiella pneumoniae, typically a benign colonizer of the human gastrointestinal tract, has emerged as an opportunistic pathogen. The emergence of multidrug-resistant (MDR) K. pneumoniae strains has exacerbated the severity and duration of hospital-associated infections and makes the treatment of these diseases a significant challenge. This study aimed to characterize local bacteriophages with lytic activity against MDR K. pneumoniae strains isolated from hospital associated infections from Senegalese patients. To achieve this, a phenotypic and genetic characterization of two phages (vKpIN31 and vKpIN32) was conducted. Among 28 MDR K. pneumoniae strains tested, phage vKpIN31 effectively lysing 15 strains encompassing 12 distinct K locus types. While phage vKpIN32 lysed 12 strains with 9 different K locus types, demonstrating broad host range activity. One-step growth analysis revealed a latent period of 25 and 20 minutes and burst sizes of 281 and 246 PFU/cell for vKpIN31 and vKpIN32 respectively. The isolated phages exhibited thermal and pH stability.  The in vitro lytic activity of phages vKpIN31 and vKpIN32 at different multiplicity of infection (1, 10?¹, and 10?³) revealed variable lysis efficacy against three K. pneumoniae strains (KP6, KP7, and KP17), with the highest effectiveness observed at an MOI of 10?³ for both phages. Also, combination of both phages as cocktail led to improved efficacy against the targeted strains Also, both phages significantly reduced biofilm levels, from 18.6% to 67.9% for 24-hour mature biofilms and from 18.1% to 58.7% for 48-hour mature biofilms. Genomic analysis identified vKpIN31 and vKpIN32 as linear dsDNA viruses belonging to the Caudoviricetes class, Demerecviridae family, Sugarlandvirus genus and Sugarlandvirus sugarland species, with estimated sizes of 77,115 bp and 109,095 bp, respectively. Notably, no genes associated with a temperate life cycle, integrases, transposable elements, antibiotic resistance, or bacterial virulence were detected in their genomes. Overall, these two phages show promise as suitable candidates for phage therapy against infections caused by MDR K. pneumoniae. Additionally, their potential extends to serving as sources for antibacterial and antibiofilm agents, signifying their clinical relevance and therapeutic potential.