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Separating Bacteria by Capsule Amount Using a Discontinuous Density Gradient
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Published on: January 7, 2019

Outer Membrane Profiles of Clonally Related Klebsiella pneumoniae

B J Vicente, M M Luis

    Methods in Molecular Medicine
    |March 5, 2011
    PubMed

    Insights

    Multidrug-resistant Klebsiella pneumoniae poses a global threat. Reduced outer membrane permeability, often due to porin loss, significantly increases resistance to antibiotics like beta-lactams and fluoroquinolones.

    Area of Science:

    • Microbiology
    • Infectious Diseases
    • Antimicrobial Resistance

    Background:

    • Multiply-antibiotic resistant (multiresistant) Klebsiella pneumoniae strains, often carrying plasmids for extended-spectrum β-lactamases (ESBLs) or AmpC-type β-lactamases (ACTBLs), complicate treatment.
    • Global incidences of these resistant strains are increasing, with significant prevalence in the US and Europe, and higher rates in nosocomial outbreaks.
    • Resistance to fluoroquinolones is common in ESBL-producing strains, likely due to mutations affecting topoisomerase genes.

    Purpose of the Study:

    • To investigate the mechanisms contributing to increased antibiotic resistance in Klebsiella pneumoniae.
    • To understand the role of outer membrane permeability and porin expression in antimicrobial resistance.
    • To identify genetic factors leading to reduced porin expression.

    Main Methods:

    • Analysis of antibiotic resistance mechanisms in Klebsiella pneumoniae.
    • Examination of the correlation between ESBL/ACTBL production and reduced outer membrane permeability.
    • Investigation of mutations in porin genes leading to decreased porin expression.

    Main Results:

    • Decreased outer membrane permeability, caused by loss or reduced expression of porins, significantly increases minimum inhibitory concentrations (MICs) for β-lactams and fluoroquinolones.
    • Reduced porin expression leads to decreased antibiotic influx and reduced access to intracellular targets.
    • Mutations in porin genes, including point mutations, deletions, and insertion sequences, are responsible for the reduction in porin expression.

    Conclusions:

    • Reduced outer membrane permeability is a critical factor in the high-level resistance observed in multiresistant Klebsiella pneumoniae.
    • Targeting porin expression or function could be a strategy to overcome antibiotic resistance in these pathogens.
    • Understanding the genetic basis of porin loss is essential for developing new therapeutic approaches against Klebsiella pneumoniae infections.

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