Building Science

Actinobacteria & Thermophilic Bacteria

Understanding filamentous bacteria commonly found in water-damaged buildings and their role in CIRS.

What are actinobacteria?

Actinobacteria are gram-positive filamentous bacteria commonly found in soil, water, and decomposing organic matter. In water-damaged buildings, they colonize moisture-damaged insulation, drywall, and HVAC systems.

Unlike mold, actinobacteria are invisible but produce potent inflammatory compounds that trigger immune responses in sensitive individuals.

Where actinobacteria thrive

Wet fiberglass insulation

Contaminated ductwork

Cellulose-based materials (drywall, paper)

HVAC returns and plenums

Crawlspaces with humidity > 60%

Basement areas with chronic moisture

Health impacts

Actinobacteria produce endotoxins and other inflammatory compounds. Exposure is associated with respiratory symptoms, chronic inflammation, and immune dysregulation — particularly in people with CIRS.

Detecting actinobacteria

Specialized testing like ERMI and qPCR can identify actinobacteria. Discovery often requires professional assessment using molecular testing methods.

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