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Updated: Jul 25, 2025
Collection and Extraction of Occupational Air Samples for Analysis of Fungal DNA
Published on: May 2, 2018
Relationship Between Airborne Fungi Presence and the Position of the High Efficiency Particulate Air Filter in the
Emiliana A Sabuco-Tébar1, Julián J Arense-Gonzalo2, F Javier Campayo-Rojas1
1Department of Preventive Medicine, "Reina Sofia" University Clinical Hospital, Murcia, Spain.
Aim:
Establish the influence of the terminal or nonterminal position of High Efficiency Particulate Air (HEPA) filters in the Heating, Ventilation, and Air Conditioning (HVAC) system on the presence of airborne fungi in controlled environment rooms.
Background:
Fungal infections are an important cause of morbidity and mortality in hospitalized patients.
Methods:
This study was realized from 2010 to 2017, in rooms with terminal and nonterminal HEPA filters, in eight Spanish hospitals. In rooms with terminal HEPA filters, 2,053 and 2,049 samples were recollected, and in rooms with nonterminal HEPA filters, 430 and 428 samples were recollected in the air discharge outlet (Point 1) and in the center of the room (Point 2), respectively. Temperature, relative humidity, air changes per hour, and differential pressure were recollected.
Results:
Multivariable analysis showed higher odds ratio (OR) of airborne fungi presence when HEPA filters were in nonterminal position (OR: 6.78; 95% CI [3.77, 12.20]) in Point 1 and (OR: 4.43; 95% CI [2.65, 7.40]) in Point 2. Other parameters influenced airborne fungi presence, such as temperature (OR: 1.23; 95% CI [1.06, 1.41]) in Point 2 differential pressure (OR: 0.86; 95% CI [0.84, 0.90]) and (OR: 0.88; 95% CI [0.86, 0.91]) in Points 1 and 2, respectively.
Conclusions:
HEPA filter in terminal position of the HVAC system reduces the presence of airborne fungi. To decrease the presence of airborne fungi, adequate maintenance of the environmental and design parameters is necessary in addition to the terminal position of the HEPA filter.
Insights
Placing High Efficiency Particulate Air (HEPA) filters in a terminal position within HVAC systems significantly reduces airborne fungi. This strategy is crucial for controlling fungal presence in healthcare environments.
Area of Science:
- Environmental microbiology
- Hospital infection control
- Air filtration technology
Background:
- Fungal infections pose a significant threat to hospitalized patients, contributing to morbidity and mortality.
- Controlling airborne fungi is essential for maintaining sterile environments in healthcare settings.
Purpose of the Study:
- To determine the impact of High Efficiency Particulate Air (HEPA) filter placement (terminal vs. nonterminal) in HVAC systems on airborne fungal presence.
- To assess the influence of environmental parameters on airborne fungi in controlled hospital rooms.
Main Methods:
- A multi-hospital study (2010-2017) in Spain comparing airborne fungi in rooms with terminal and nonterminal HEPA filters.
- Collected 2,053-2,049 samples (Point 1) and 430-428 samples (Point 2) from terminal and nonterminal HEPA filter rooms, respectively.
- Monitored temperature, relative humidity, air changes per hour, and differential pressure.
Main Results:
- Nonterminal HEPA filter placement was associated with a significantly higher presence of airborne fungi (OR: 6.78 in Point 1, OR: 4.43 in Point 2).
- Increased temperature and reduced differential pressure also correlated with higher airborne fungi levels.
- Terminal HEPA filter positioning demonstrated a clear reduction in airborne fungal presence.
Conclusions:
- Terminal positioning of HEPA filters in HVAC systems is effective in reducing airborne fungi.
- Optimal environmental and design parameters, alongside terminal HEPA filter placement, are necessary for comprehensive airborne fungi control.
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