Assessment of fungal and bacterial bioaerosols in ambient air in Fairbanks, Alaska

Abstract

Bioaerosols are solid or liquid particles of biological origin that are suspended in the surrounding air or other gaseous environments. Bioaerosols can cause diseases, allergenic or toxicological reactions, respiratory distress, and can be potential bioterrorism threats. Studies concerning ambient bioaerosols have never focused upon central Alaska, and only one experiment has utilized the DRUM (Davis Rotating Unit for Monitoring) impactor as the collection apparatus. This study focuses on the assessment and identification of fungi and bacteria present in the ambient air collected by the DRUM impactor from March 2008 to January 2009. The samples were collected on MylarTM and aluminum substrates (with or without apiezon coating) and subjected to DNA extraction and nested PCR using universal primers for the 16S rRNA gene in bacteria and ITS (internal transcribed spacer) region in fungi. The PCR products were used to generate a clone library, and selected clones from each sample clone library were sequenced. Sequences were taxonomically classified using BLAST for fungal identification and RDP Pipeline for bacterial identification to the genus level. Numerous species of bacteria (i.e., Ralstonia sp., Bradyrhizobium sp., Sphingomonas sp.) and fungi (i.e. Fusarium sp., Cladosporium sp., Penicillium sp.) were identified from the clone libraries, thus indicating that the DRUM impactor has potential for monitoring biological content in the air. The resulting patterns in bacteria and fungi during the course of the year indicate that the DRUM sampler may also have the potential to detect fluctuations in populations that result from meteorological conditions, seasonal cycles, and climatic conditions.