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Phospholipid Transporter MlaFEDCB Regulates Klebsiella pneumoniae Virulence by Modulating Fimbriae Synthesis and

Xiaoyu Zhao1,2, Haoqi Liu1,2, Qinglan Guo1,2

  • 1Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.

The Journal of Infectious Diseases
|October 7, 2025
PubMed
Abstract

Insights

The mlaFEDCB gene cluster in Klebsiella pneumoniae enhances bacterial virulence by increasing adhesion and adaptability. Deleting this cluster significantly improves survival in mice and reduces bacterial fimbriae and adherence.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Pathogenesis

Background:

  • Klebsiella pneumoniae is a significant opportunistic pathogen with emerging hyper-virulent strains.
  • The phospholipid transporter MlaFEDCB is linked to bacterial virulence, but its regulatory mechanisms are not fully understood.

Purpose of the Study:

  • To investigate the role of the mlaFEDCB gene cluster in regulating Klebsiella pneumoniae virulence.
  • To elucidate the mechanisms by which mlaFEDCB influences bacterial adaptation and host interaction.

Main Methods:

  • Homology analysis of the mlaFEDCB gene cluster.
  • Murine intraperitoneal infection models.
  • Transcriptomic analysis to assess gene expression.
  • Electron microscopy (SEM, TEM) to visualize fimbrial structures.
  • Adhesion assays with bladder epithelial cells.
  • Growth assays under stress conditions.

Main Results:

  • The mlaFEDCB gene cluster is conserved and co-transcribed in gram-negative bacteria.
  • Deletion of mlaFEDCB (KP-ΔmlaFEDCB) significantly increased mouse survival and reduced fimbrial structures and host cell adhesion.
  • Transcriptomic analysis revealed altered expression of virulence genes, including fimH and fimD, in the mutant strain.
  • KP-ΔmlaFEDCB exhibited compromised growth under stress conditions compared to wild-type K. pneumoniae.

Conclusions:

  • The mlaFEDCB gene cluster is crucial for Klebsiella pneumoniae virulence.
  • mlaFEDCB modulates virulence gene expression, pilus synthesis, and environmental adaptability.
  • Targeting mlaFEDCB could be a strategy to combat K. pneumoniae infections.
Keywords:
Klebsiella pneumoniaemlaFEDCBphospholipid transportertype 1 fimbriaevirulence

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