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Published on: April 2, 2013

Surface topography and fine structure of the Legionnaires' disease bacterium. A study of six isolates from

T R Neblett, J M Riddle, M Dumoff

    Annals of Internal Medicine
    |April 1, 1979
    PubMed

    Insights

    Researchers characterized six clinical isolates of the Legionnaires' disease bacterium from Michigan hospitals. Electron microscopy revealed bacillary shapes, wrinkled surfaces, and gram-negative cell wall structures, with no spores observed.

    Area of Science:

    • Microbiology
    • Bacteriology
    • Microscopy

    Background:

    • Legionnaires' disease is a severe pneumonia caused by Legionella bacteria.
    • Clinical isolates provide valuable insights into bacterial morphology and characteristics.

    Purpose of the Study:

    • To characterize the morphology of clinical isolates of the Legionnaires' disease bacterium.
    • To compare the ultrastructure of these isolates using electron microscopy.

    Main Methods:

    • Isolation and in vitro cultivation of six clinical Legionella strains from Michigan hospitals.
    • Scanning Electron Microscopy (SEM) to observe external cell morphology.
    • Transmission Electron Microscopy (TEM) to analyze internal cell structure.

    Main Results:

    • SEM revealed bacillary, curved, and spindle shapes, with some resembling rolling pins. Cell dimensions ranged from 0.29-0.39 µm in width and 1.60-2.34 µm in length, with filamentous forms up to 9.8 µm.
    • Bacterial surfaces appeared wrinkled compared to Escherichia coli.
    • TEM showed a multilayered, irregular cell wall characteristic of Gram-negative bacteria, plasma membrane, periplasmic space, nucleoid, ribosomes, and vacuoles. No spores were observed.

    Conclusions:

    • The studied Legionnaires' disease bacterium isolates exhibit diverse morphologies and wrinkled surfaces.
    • Ultrastructural analysis confirms typical Gram-negative bacterial features without evidence of spores.

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