Abstract: Objective To explore the possible relationship between environmental contamination by Aspergillus and invasive aspergillosis.Methods From November 2005 to October 2006,samples were collected from the environment (air in corridors,air in wards,surfaces and tap water) twice a month,and from patients (nose,pharynx and sputum) at a liver transplantation department (LTD),neurologic surgery intensive care unit (NSICU) and central intensive care unit (CICU) in our hospital,and subjected to fungal culture.The Aspergillus density was determined in these environments.The isolates of Aspergillus flavus were genotyped by random amplification of polymorphic DNA (RAPD) assay to investigate the origin of infection.Results The mean aspergillus density was 12,10.75,0 and 20 cfu/m³ at LTD,NSICU,CICU and corridors respectively.The five most prevalent species of aspergillus in these environments in decreasing order were Aspergillus flavus,Aspergillus fumigatus,Aspergillus niger,Aspergillus versicolor and Aspergillus clavatus.RAPD demonstrated that the genotypes ofA.flavus isolated from two patients were identical to those of the environmental strains in NSICU.The A.flavus genotypes from 3 patients in CICU were all different from those of the environment strains in CICU,but the genotypes were identical from two of the three patients.Conclusions Aspergillus contamination of different degree does exist at LTD,NSICU and CICU. The genotypes of A.flavus are identical from patients and environment in NSICU,suggesting that the clinical infection may originate from hospital environment.

Key words: Aspergillus, Aspergillosis, Environmental pollution, Intensive care units