Phenotypic heterogeneity and genetic mechanisms of phage resistance in hypervirulent carbapenem-resistant Klebsiella pneumoniae.

Four distinct phage resistance phenotypes, primarily involving wcaJ mutations, were identified in hypervirulent carbapenem-resistant Klebsiella pneumoniae, enabling evasion of phage infection.

• Why it matters: Understanding the diverse phenotypic and genetic mechanisms of phage resistance is essential to improve phage therapy effectiveness against multidrug-resistant bacteria, which pose significant clinical challenges.
• What they did: Researchers examined K2-serotype CR-hvKP under phage Kpph1 pressure, identifying resistance strategies such as receptor masking and community resistance, with wcaJ mutations being predominant; they also isolated a secondary phage, K2V3, targeting wcaJ mutants.
• The result: A phage cocktail combining Kpph1 and K2V3 successfully suppressed resistant strains and prevented further resistance development, advancing strategies for effective clinical phage therapy against resistant bacterial pathogens.