Could we predict airborne Aspergillus contamination during construction work?

BACKGROUND Aspergillus fumigatus is a major opportunistic pathogen causing nosocomial infection. Hospital outbreaks of invasive aspergillosis have been associated with demolition and building construction. This study was designed to examine the impact of meteorologic factors and different periods of work on outdoor fungal airborne concentrations. METHODS The study was conducted at Necker Enfants Malades Hospital, a 650-bed teaching care hospital recently involved in a large construction program, including renovation, construction, and demolition. During the work phases, prospective external air samplings were performed 3 times a week, and meteorologic parameters were collected every day. RESULTS Two hundred and one samples were collected. Aspergillus spp were found in 80.1% of samples, with a median concentration of 16 colony forming units (CFU)/m3. A significant increase in the colony count of molds occurred after demolition. In the multivariate analysis, factors associated with overall fungi concentration were the type of work construction and temperature. Elevated Aspergillus spp concentrations (>20 CFU/m3) were associated with higher temperature. CONCLUSIONS Our findings underline the importance of environmental surveillance. According to our results we suggest that demolition work should be performed during the winter and fall seasons.