Phage-Encoded Depolymerase DepKP144 with Therapeutic Potential Against Both K1- and K2-Type Klebsiella pneumoniae.

Multidrug resistance (MDR) is a global problem for the healthcare system, complicating the therapy of bacterial infections. It is noted that patients infected with MDR strains often require prolonged hospitalization, have a high risk of mortality, and remain vulnerable to reinfection after recovery. In this study, recombinant phage-encoded depolymerase DepKP144 was produced using the Escherichia coli expression system and purified. The depolymerase DepKP144 protein was able to reduce viable bacterial counts following capsule degradation in 95% of the tested strains of type K1 and 85% of the tested strains of type K2 Klebsiella pneumoniae. The depolymerase DepKP144 was active against K. pneumoniae K1-type and K2-type planktonic cells and destroyed the biofilms formed by clinical MDR strains of K. pneumoniae. In in vivo experiments, DepKP144 at a dose of 180 μg/mouse resulted in a 50% survival of the mice infected with K2-type K. pneumoniae and in a 17% survival of the mice infected with K1-type K. pneumoniae. This depolymerase is promising for further development of prevention and therapeutic candidates against MDR K. pneumoniae.