Monitoring environmental Aspergillus spp. contamination and meteorological factors in a haematological unit

Area of Science:

• Environmental microbiology
• Hospital epidemiology
• Mycology

Background:

• Aspergillus species are common airborne fungi influenced by meteorological conditions.
• High Aspergillus conidia concentrations in hospital environments pose a risk for invasive fungal diseases in immunocompromised patients.

Purpose of the Study:

• To assess airborne Aspergillus conidia contamination variability in a Haematological Unit (HU) over 16 months.
• To correlate Aspergillus conidia levels with meteorological parameters and a seasonal indicator.

Main Methods:

• Environmental Aspergillus surveillance using agar impact samplers in HU rooms, bathrooms, corridors, and external sites.
• Recording local temperature and relative humidity; obtaining external wind speed and rainfall data.
• Statistical analysis to determine relationships between Aspergillus conidia concentrations, environmental factors, and a seasonal indicator.

Main Results:

• Significant differences in Aspergillus conidia concentration were found across sampling sites.
• Internal Aspergillus loads correlated with temperature, internal relative humidity, and rain.
• External conidia concentrations were influenced by outdoor temperature and relative humidity.
• A seasonal indicator significantly affected Aspergillus distribution inside the HU.
• Aspergillus fumigatus was the most prevalent species, with its distribution linked to the seasonal indicator both indoors and outdoors.

Conclusions:

• Airborne Aspergillus conidia contamination in a Haematological Unit is significantly influenced by meteorological factors and seasonality.
• Environmental monitoring and understanding these correlations are vital for infection control in immunocompromised patient settings.
• Aspergillus fumigatus requires specific attention due to its high prevalence and seasonal dependence.