In recent years, Klebsiella pneumoniae has caused an increase in the number of serious infections associated with pneumonia, septicemia, urinary tract infections, and pyogenic liver abscess. In this study, a phage P929, isolated from hospital sewage in Jiangsu, could specifically infect K. pneumoniae KL19 capsular type by forming plaques with a translucent halo that expanded over time. Phage P929 with a multiplicity of infection (MOI) of 0.1 produced the highest phage titer. According to a one-step growth curve experiment, the latent time period of phage P929 was 25 min, and the burst size was about 156 phage particles/cell. The sensitivity tests confirmed that P929 was stable at temperatures ranging from 4 to 50 °C and pH 3 to 11. Based on morphological observation and phylogenetic analysis, phage P929 could be assigned to a new species in the genus Drulisvirus of the subfamily Slopekvirinae in the family Autographiviridae. According to genome analysis, phage P929 was 44,764 bp in size with 53.66% G + C content, encoding 57 proteins or coding sequences (117-3699 bp in length). Phage P929 showed potential antibacterial activity on planktonic cells and biofilm. After 120 min, the OD600 values of five phage-treated groups were basically reached zero compared to the untreated group, and the antibacterial activity of P929 was still detectable within 390 min. In anti-biofilm tests, phage P929 at an MOI of 1 significantly reduced the biofilm formation of K. pneumoniae in 48 h. These results suggest that phage P929 may be used to treat carbapenem-resistant and biofilm-forming K. pneumonia in clinical settings.
