107 Abundance and Diversity of Microbial Community in Bioaerosol Samples Taken from a French Cheese Dairy

Abstract

Abstract Bioaerosol samples were taken at a cheese company producing about ten different products. The aims were (i) to investigate airborne microbial community (quantity/diversity) using molecular analytical methods and (ii) to appreciate how molecular methods improve the characterization of bioaerosols. Ambient bioaerosol samples were performed using 37-mm 3-pieces closed-face polypropylene cassettes equipped with 0.8 µm pore size polycarbonate membrane at 2 or 10 L.min-1, in several work areas during winter and summer seasons. Airborne bacteria and fungi were quantified by counting colonies on culture media and by quantitative PCR (qPCR). The microbial community was identified using 16SrRNA and ITS1 genes high-throughput sequencing with sequence analysis performed on the Galaxy Migale platform using the FROGS data processing pipeline. The results showed that ambient concentration levels were working area dependent. A massive emission of microorganisms into the air was found in areas in which a brushing task of cheeses was performed, leading to high concentrations of cultivable (up to 107 CFU/m3) and total (up to 1010 18SrRNA copies/m3) fungi. The correlation between cultivable and total mold is discussed and individual exposures are evoked. The microbial community was characterized by the predominance of the fungal genus Penicillium and their species composition depended on the type of cheese or season. This work has shed new light on these still poorly documented work situations and is essential to refine the diagnosis of the immunoallergic risks of the workers concerned. The presentation discusses the complementarity between culture-based and molecular-based methods for the assessment of bioaerosols.