Airborne Aspergillus fumigatus spore concentration during demolition of a building on a hospital site, and patient risk determination for invasive aspergillosis including azole resistance

Abstract

Invasive aspergillosis (IA) in immunocompromised patients has been associated with demolition in or adjacent to hospitals. In recent years, azole-resistant clinical isolates of Aspergillus fumigatus, the most common agent of IA, have emerged in Western Europe and are spreading globally. To determine the potential risk of IA, including azole resistance, in patients caused by demolition of a hospital building. Air sampling before, during and after demolition, screening for azole resistance, genotyping of non-susceptible isolates, and comparing those with strains from patients with azole-resistant IA during demolition. Mean concentrations of A.fumigatus spores did not differ significantly between the three periods before [17.5colony-forming units (cfu)/m³], during (20.8cfu/m³) (P=0.26) and after (17.7cfu/m³) demolition (P=0.33). No significant difference in IA cases documented by clinicians was found when comparing the timeframe of demolition with the previous year (44 vs 42 cases). Thirty of 200 A.fumigatus isolates (15%) showed azole resistance. Genotyping by microsatellite polymerase chain reaction of the azole-resistant environmental and clinical isolates showed a polyclonal distribution. The results suggest that with implemented preventive measures, there is no increased risk for IA, including azole resistance, in immunocompromised patients during outdoor demolition work. Further prospective studies are needed to confirm these findings.