Aspergillus Was the Dominant Genus Found during Diversity Tracking of Potentially Pathogenic Indoor Fungal Isolates

Area of Science:

• Mycology
• Environmental Health
• Indoor Air Quality

Background:

• Viable airborne pathogenic fungi are a health concern, especially for vulnerable populations.
• Indoor environments can harbor fungal species with pathogenic potential.
• Assessing fungal pathogenicity is crucial for public health and building safety.

Purpose of the Study:

• To screen a collection of indoor fungal isolates for pathogenic potential.
• To identify fungal species capable of growing at human body temperature (37 °C) and neutral pH.
• To investigate the presence of opportunistic and less likely pathogenic fungi in problematic and ordinary buildings.

Main Methods:

• Screening of 284 indoor fungal isolates for growth at 37 °C and 30 °C at neutral pH.
• Categorization of isolates based on growth characteristics at different temperatures.
• Species-level identification of selected fungal strains using standard mycological techniques.
• Isolation of fungi from 20 indoor locations (14 problematic, 6 ordinary).

Main Results:

• 67 isolates grew at 37 °C and neutral pH, identified as potential opportunistic pathogens.
• 47 isolates grew at 30 °C but not 37 °C, considered less likely pathogens.
• Problematic buildings yielded known opportunistic pathogens (e.g., Aspergillus calidoustus) and less likely pathogens (e.g., Aspergillus versicolor).
• Aspergillus was the most dominant and diverse genus identified.
• Tolerance to cleaning chemicals may aid Aspergillus adaptation to indoor environments.

Conclusions:

• Certain indoor fungal species, particularly Aspergillus, exhibit pathogenic potential and are prevalent in buildings.
• The ability to grow at 37 °C is a key indicator of opportunistic fungal pathogens in indoor environments.
• Further research into fungal adaptation mechanisms, such as chemical tolerance, is warranted to mitigate indoor air quality risks.