Epidemiological study of invasive pulmonary aspergillosis in a haematology unit by molecular typing of environmental and patient isolates of Aspergillus fumigatus.

In order to determine the possible relationship between environmental contamination by Aspergillus fumigatus and occurrence of invasive aspergillosis, a one-year prospective study was carried out in the haematology ward of Hautepierre Hospital, Strasbourg, France. During the study period, 21 environmental isolates and 26 clinical isolates of A. fumigatus were collected. Each was genotyped using a random amplification of polymorphic DNA (RAPD) technique. Thirty-four distinct profiles were identified by RAPD analysis, indicating the great genetic diversity of A. fumigatus isolated from infected patients and from the environment. For two patients, RAPD analysis demonstrated concurrent infection by at least two different strains. In two cases, a genetic similarity was noted between isolates obtained from a patient and from the environment.