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Flagella on Legionnaires' disease bacteria: ultastructural observations
Annals of Internal Medicine
|November 1, 1980
Summary
Electron microscopy revealed flagellated Legionella pneumophila with unique basal bodies and fimbriae. These findings offer new insights into the ultrastructure of this important bacterial pathogen.
Area of Science:
- Microbiology
- Bacteriology
- Cell Biology
Background:
- Legionella pneumophila is a Gram-negative bacterium known to cause Legionnaires' disease.
- Previous studies have described its morphology, but detailed ultrastructural analysis, particularly of flagellar apparatus and fimbriae, is limited.
Purpose of the Study:
- To conduct detailed ultrastructural investigations of five strains of flagellated Legionella pneumophila using scanning and transmission electron microscopy.
- To characterize the morphology of flagella, fimbriae, and flagellar basal bodies in L. pneumophila.
Main Methods:
- Culturing of five L. pneumophila strains on charcoal yeast extract agar and yeast extract broth for 1-3 days.
- Examination of bacterial morphology using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
- Analysis of flagellar structure, diameter, basal bodies, and fimbriae (streamers).
Main Results:
- Observed pleomorphic, flagellated bacilli with typical pinching division.
- Identified a single, polar flagellum (approx. 25 nm diameter) in most strains.
- TEM revealed unique, bulbous flagellar basal bodies, distinct from other Gram-negative bacteria.
- Identified fimbriae (streamers) with approximately half the diameter of flagella, exhibiting coiled and bent structures.
Conclusions:
- Legionella pneumophila possesses a distinct ultrastructure, including unique flagellar basal bodies.
- Fimbriae, previously observed as streamers, are confirmed and characterized.
- These ultrastructural details contribute to understanding L. pneumophila's motility and surface structures.
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