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Pseudomonas aeruginosa Induced Lung Injury Model

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Published on: October 29, 2014

PNEUMONIC LESIONS CAUSED BY BACILLUS MEGATHERIUM.

M Wollstein¹, S J Meltzer

¹Departments of Pathology and of Physiology and Pharmacology of The Rockefeller Institute for Medical Research, New York.

The Journal of Experimental Medicine

|October 30, 2009

Summary

Saprophytic bacteria, like Bacillus megatherium, can cause pulmonary lesions resembling lobar pneumonia in experiments. These lesions show rapid development and resolution, differing quantitatively from typical bacterial pneumonia.

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Published on: April 7, 2015

Area of Science:

Microbiology
Pathology
Pulmonary Medicine

Background:

Pneumonia is often associated with virulent bacterial pathogens.
The role of saprophytic bacteria in inducing pulmonary inflammation is less understood.

Purpose of the Study:

To investigate the capacity of the saprophytic bacterium Bacillus megatherium to induce pulmonary lesions.
To characterize the pathological features and temporal progression of experimentally induced lung lesions.

Main Methods:

Intranasal inoculation of Bacillus megatherium in experimental models.
Gross and microscopic examination of pulmonary tissues.
Assessment of lesion development, extent, and resolution over time.

Main Results:

Bacillus megatherium induced distinct pulmonary lesions grossly resembling lobar pneumonia.
Lesions featured intense, non-fibrinous, leucocytic exudation without significant bacterial presence or invasion.
Inflammation peaked within 24 hours, with resolution beginning by the third day, and no phagocytosis was observed.

Conclusions:

Saprophytic bacteria can produce pneumonic lesions similar in appearance to mild lobar pneumonia.
The induced lesions differ quantitatively, not qualitatively, from those caused by avirulent pneumococci.
Other saprophytes may similarly cause pneumonia-like lesions.