Settleable Dust and Bioburden in Portuguese Dwellings.

Carla Viegas,Célia Alves,Elisabete Carolino,Beatriz Almeida,Marta Dias,Liliana Aranha Caetano,Estela Vicente

doi:10.3390/microorganisms8111799

Abstract

Monitoring campaigns in several buildings have shown that occupants exposed to contaminated indoor air generally exhibit diverse health symptoms. This study intends to assess settleable dust loading rates and bioburden in Portuguese dwellings by passive sampling onto quartz fiber filters and electrostatic dust cloths (EDCs), respectively. Settled dust collected by EDCs was analyzed by culture-based methods (including azole-resistance screening) and qPCR, targeting four different toxigenic Aspergillus sections (Flavi, Fumigati, Circumdati, and Nidulantes). Dust loading rates and bioburden showed higher variability in the summer season. In both seasons, Penicillium sp. was the one with the highest prevalence (59.1% winter; 58.1% summer), followed by Aspergillus sp. in winter (13.0%). Fungal contamination increased in the winter period, while bacterial counts decreased. Aspergillus sections Circumdati and Nidulantes, detected in voriconazole supplemented media, and Aspergillus sections Fumigati and Nidulantes, detected by molecular tools, were found in the winter samples. This study reinforces the importance of applying: (a) Passive sampling methods in campaigns in dwellings; (b) two different culture media (MEA and DG18) to assess fungi; (c) in parallel, molecular tools targeting the most suitable indicators of fungal contamination; and (d) azole resistance screening to unveil azole resistance detection in fungal species.

Highlights

According to the World Health Organization (WHO), 4.3 million people die each year from exposure to domestic air pollution
People spend more than 90% of the day indoors in their own dwellings or in workplace [1,2], so it is of utmost importance to study indoor air quality (IAQ)
As in dust loading rates, bioburden presented a wider range in the summer season

Summary

Introduction

According to the World Health Organization (WHO), 4.3 million people die each year from exposure to domestic air pollution. People spend more than 90% of the day indoors in their own dwellings or in workplace [1,2], so it is of utmost importance to study indoor air quality (IAQ). Organic dust consists mainly of particulate matter with microbial, vegetable, or animal origin. Bioaerosols are usually defined as particulate matter with biological origin, such as pollen, plant fibers, and microorganisms. Exposure to bioaerosols can lead to a wide range of adverse health effects [5,6,7,8]. Fungi and bacteria present in bioaerosols are often called as the bioburden and should be well characterized [9]

Methods

Results

Discussion

Conclusion