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Enhancing the Antibacterial Activity of Endolysin against Klebsiella pneumoniae through Fusion Engineering Using

Kexuan Gao1, Yuhui Li1,2, Yuxuan Wang1

  • 1College of Life Sciences, Shihezi University, Shihezi City, Xinjiang 832003, P. R. China.

Journal of Microbiology and Biotechnology
|June 15, 2026
PubMed

Insights

A novel fusion protein, LysK1-Sub5, effectively targets multidrug-resistant Klebsiella pneumoniae by overcoming outer membrane barriers. This engineered endolysin shows significant potential as a topical antimicrobial agent for wound infections.

Area of Science:

  • Microbiology
  • Biotechnology
  • Antimicrobial Research

Background:

  • Multidrug-resistant (MDR) Klebsiella pneumoniae poses a significant clinical challenge, necessitating novel therapeutic strategies.
  • Endolysins, phage-derived enzymes, show promise as antimicrobials but face limitations against Gram-negative bacteria due to the outer membrane (OM).
  • Overcoming the OM barrier is critical for endolysin efficacy against Gram-negative pathogens.

Purpose of the Study:

  • To engineer a novel endolysin capable of penetrating the OM of Klebsiella pneumoniae.
  • To evaluate the synergistic antimicrobial activity of an endolysin fused with an antimicrobial peptide (AMP).
  • To assess the efficacy of the engineered endolysin in a preclinical wound infection model.

Main Methods:

  • Fusion of the antimicrobial peptide Sub5 with the endolysin LysK1 to create LysK1-Sub5.
  • Determination of minimum inhibitory concentrations (MICs) against Klebsiella pneumoniae.
  • Assessment of antimicrobial activity without OM permeabilizers.
  • Evaluation of environmental tolerance and lytic spectrum.
  • In vivo testing using a mouse skin wound infection model.

Main Results:

  • LysK1-Sub5 demonstrated a 2.7 to 6.1-fold reduction in MIC compared to LysK1 alone.
  • LysK1-Sub5 inhibited Klebsiella pneumoniae growth within 16 hours without OM permeabilizers.
  • The fusion protein exhibited stable environmental tolerance and broad-spectrum lytic activity.
  • In vivo studies showed accelerated wound healing and reduced bacterial load in infected mice.
  • LysK1-Sub5 proved effective in reducing Klebsiella pneumoniae topical infection.

Conclusions:

  • The engineered LysK1-Sub5 effectively penetrates the OM of Klebsiella pneumoniae, enabling potent antimicrobial activity.
  • LysK1-Sub5 represents a promising topical antimicrobial agent for treating Klebsiella pneumoniae infections.
  • This approach offers a viable strategy to enhance endolysin efficacy against Gram-negative bacteria.
Keywords:
Antimicrobial activityAntimicrobial peptideEndolysinKlebsiella pneumoniaeSkin infection

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