Investigation of Sources, Diversity, and Variability of Bacterial Aerosols in Athens, Greece: A Pilot Study

Abstract

We characterized the composition, diversity, and potential bacterial aerosol sources in Athens’ urban air by DNA barcoding (analysis of 16S rRNA genes) during three seasons in 2019. Air samples were collected using the recently developed Rutgers Electrostatic Passive Sampler (REPS). It is the first field application of REPS to study bacterial aerosol diversity. REPS samplers captured a sufficient amount of biological material to demonstrate the diversity of airborne bacteria and their variability over time. Overall, in the air of Athens, we detected 793 operational taxonomic units (OTUs), which were fully classified into the six distinct taxonomic categories (Phylum, Class, Order, etc.). These OTUs belonged to Phyla Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes, Cyanobacteria, and Fusobacteria. We found a complex community of bacterial aerosols with several opportunistic or potential pathogens in Athens’ urban air. Referring to the available literature, we discuss the likely sources of observed airborne bacteria, including soil, plants, animals, and humans. Our results on bacterial diversity are comparable to earlier studies, even though the sampling sites are different or geographically distant. However, the exact functional and ecological role of bioaerosols and, even more importantly, their impact on public health and the ecosystem requires further air monitoring and analysis.

Capturing the Aerobiome: Application of Polyurethane Foam Disk Passive Samplers for Bioaerosol Monitoring

“…The bacterial communities were dominated by Proteobacteria , Actinobacteria , Firmicutes , and Bacteroidota , with Proteobacteria (Figure ) being the most dominant in both PUF-disk type passive air samplers and Hi-Vol active air samplers. This has similarly been identified in other ambient air samples in France, , China, , Germany, over the Great Barrier Reef (Australia), Greece, and Rwanda, in which similar next-generation sequencing methods were also used. The airborne bacterial communities sampled in this study with PUF disks and Hi-Vol active air samplers contained similar phyla.…”

Comparison of Airborne Bacterial Populations Determined by Passive and Active Air Sampling at puy de Dôme, France

“…During the assembly of REPS, its holder and bases were cleaned, disinfected, and irradiated with UV light for 15 minutes. The ferroelectric films were disinfected with 70% (v/v) ethanol and rinsed with sterile water (Therkorn et al, 2017a;Metaxatos et al, 2022). The samplers were assembled at Rutgers based upon previous designs (Therkorn et al, 2017a;Metaxatos et al, 2022) and shipped in sterile 50 mL conical tubes to Clermont-Ferrand, France for sampling at puy de Dôme.…”

“…The ferroelectric films were disinfected with 70% (v/v) ethanol and rinsed with sterile water (Therkorn et al, 2017a;Metaxatos et al, 2022). The samplers were assembled at Rutgers based upon previous designs (Therkorn et al, 2017a;Metaxatos et al, 2022) and shipped in sterile 50 mL conical tubes to Clermont-Ferrand, France for sampling at puy de Dôme. At the sampling site, REPS were placed in a small protective cage within five meters of the PM10 sampler.…”

“…It has been shown to effectively collect bioaerosols up to 21 days in the outdoor environment (Grogan and Mainelis, 2022). Furthermore, REPS was deployed to sample air in Greece and detected 793 bacterial operational taxonomic units (OTUs) by sequencing part of the 16S rRNA gene (Metaxatos et al, 2022). However, REPS's ability to determine airborne bacterial diversity has not been compared to other samplers.…”