Prospective Environmental Surveillance of Aspergillus spp. During Hospital Renovation: Evidence of Potential Fungal Dissemination Through Shared Ceiling Voids

Background: Hospital construction and renovation are recognized risk factors for healthcare-associated aspergillosis because demolition work can disperse airborne fungal spores into the air. However, environmental dissemination pathways during renovations remain incompletely understood. Methods: We conducted a prospective environmental surveillance study during the renovation of a high-care unit (HCU) at a 1000-bed tertiary care hospital in Japan. Air sampling was performed before, during, and after the renovation at five locations using an air sampler (500 L/sample). Fungal isolates were identified using internal transcribed spacer sequencing. Dust collected from the ceiling void above the HCU before the renovation was also cultured. Results: Aspergillus fumigatus was isolated from dust collected from the ceiling void before renovation. During renovation, Aspergillus spp. were detected only in areas sharing the ceiling void with the construction site and on the floor immediately below the renovation area. No Aspergillus spp. were detected in the intensive care unit, which did not share the ceiling void. These findings suggest that demolition-related vibrations may have disturbed dust accumulated within the ceiling voids, suggesting a possible mechanism for localized fungal dissemination. Additionally, to assess the clinical impact of the renovation, the quarterly number of patients with positive Aspergillus-related microbiological or serological findings from 2015 to 2025 was reviewed. No apparent increase in the number of patients with positive Aspergillus-related microbiological or serological findings was observed during the renovation period. Our findings suggest that connected ceiling voids may represent potential pathways for localized fungal dispersal during demolition, while emphasizing that this proposed pathway was not directly confirmed. Conclusions: These findings highlight the importance of environmental surveillance and appropriate infection control measures during hospital renovation.