Two Sugarlandvirus phages reveal potential use against Klebsiella pneumoniae infections
Alessa Jane Sumera1*, Edelca Panisales1, Timothy Mendoza1, Ron Leonard Dy1
- University of the Philippines Diliman
Klebsiella pneumoniae is declared by the World Health Organization as one of the top priority pathogens for creation of antibiotics. The prevalence of extended spectrum β-lactamase (ESBL)-producing and Carbapenem-resistant K. pneumoniae in nosocomial infections poses a grave threat to public health and calls for the development of alternative treatments. Bacteriophages or phages, known as bacteria-infecting viruses, are among the most abundant biological entities on the planet. With the low rate of antibiotic discovery in recent years, phages have re-emerged as potential antimicrobial agents that can be sustainably developed against multidrug resistant bacteria. In this study, 13 phages against clinical isolates of K. pneumoniae (ATCC 13887, NCTC 13438, BIOTECH 1754) with different plaque morphologies were isolated from several wastewater sources. Three phages (KP7-S1.1, KP7-JS3.1, and KP7-JS8.2) that exhibited broad host range capable of lysing the three K. pneumoniae hosts were prioritized. These phages, along with KP7-S2.1, were chosen for long-read sequencing due to their capacity to infect at least two K. pneumoniae hosts. Comparative genomic analyses revealed KP7-S1.1 and KP7-JS3.1 belonged to the genus Sugarlandvirus under the class of tailed Caudoviricites. KP7-S1.1 and KP7-JS3.1 have genome sizes ranging 109,931 – 112,834 bp and contain structural, metabolic, replication, and tRNA-encoding genes with no apparent antimicrobial resistance, lysogenic and virulence genes which strongly suggests both phages are strictly lytic. A capsule depolymerase was identified among the tail proteins of KP7-S1.1 which may be used by the phage to depolymerize the capsular polysaccharide layer of K. pneumoniae to allow access to receptors during phage infection. Overall, KP7-S1.1 and KP7-JS3.1 are viable candidates as antimicrobial agents. Further studies, such as determining their expanded host ranges and infection dynamics, will be important before these can be fully developed and harnessed for phage therapy.