Exposure to fungi, bacteria, and endotoxin in a museum, with staff reporting work-related symptoms

Occupational exposure to airborne fungi in indoor environments may pose respiratory health risks. This study aimed to characterize exposure to fungi, bacteria, and endotoxin in a historical museum where the staff reported airway symptoms. Air samples were collected during three separate workdays using personal and stationary samplers. Fungi and bacteria were quantified and identified using MALDI-TOF MS, and the total inflammatory potential was measured through Reactive Oxygen Species (ROS) production in a human cell line. The geometric mean of staff exposure was 5.9 × 10³ CFU/m³ fungi, 1.8 × 10³ CFU/m³ bacteria, and 7.93 EU/m³ endotoxin. Staff reported symptoms of the airways, with immediate symptoms upon entering two departments, which exhibited elevated fungal concentrations compared to other departments. The most prevalent fungal species were Aspergillus conicus, A. domesticus, A. pseudoglaucus, A. pseudogracilis, and Cladosporium spp. Concentrations of bacteria were highest when staff were present and without dominance by any particular species. Staff exposure and stationary samples induced ROS production in a cell line, which correlated with concentrations of fungi, bacteria, and endotoxin. Fungi were detected on the museum artifacts, and concentrations of fungi and bacteria increased during handling of the artifacts. In conclusion, staff in the two departments where airway symptoms were reported were exposed to 2 × 10⁴ to 7 × 10⁴ CFU/m³ of fungi, primarily Aspergillus spp. and Cladosporium. spp. This exposure constituted both xerophilic species and species commonly found in water-damaged buildings, and they seemed to have developed on artifacts. These findings underscore the importance of developing preventive strategies to protect the health of museum staff. Moreover, it highlights the challenge of managing fungi adapted to varying humidity conditions.