Scanning electron microscopy of Legionella pneumophila in clinical tissue

Area of Science:

• Microbiology
• Pathology
• Microscopy

Background:

• Legionnaires' disease is caused by Legionella pneumophila.
• Accurate identification and characterization of bacteria are crucial for understanding disease pathogenesis.

Purpose of the Study:

• To investigate the in situ morphology and anatomical distribution of Legionella pneumophila in autopsy tissues using scanning electron microscopy (SEM).

Main Methods:

• Scanning electron microscopy (SEM) was employed on autopsy tissues from three patients with Legionnaires' disease.
• Tissues examined included lung and extra-pulmonic sites.

Main Results:

• SEM enabled detailed visualization of Legionella pneumophila's three-dimensional morphology, revealing pleomorphism (rod or sausage-shaped) and varied surface textures (smooth, dimpled, wrinkled).
• Bacteria were observed in good condition, both intra- and extracellularly, in lung, tracheal lymph node, and heart tissues.
• Evidence of binary fission and potential flagella was noted in clinical specimens.

Conclusions:

• SEM is a valuable tool for rapid detection and morphological characterization of Legionella pneumophila in clinical samples.
• The study confirmed the pleomorphic nature of the bacterium and its presence in various anatomical locations in fatal cases of Legionnaires' disease.