Invasive aspergillosis: epidemiology and environmental study in haematology patients (Sfax, Tunisia).

Invasive aspergillosis (IA) is a major opportunistic infection in haematology patients. Preventive measures are important to control IA because diagnosis is difficult and the outcome of treatment is poor. We prospectively examined the environmental contamination by Aspergillus and other fungal species and evaluated the prevalence of invasive aspergillosis in the protect unit of haematology. A three-year prospective study (December 2004-September 2007) was carried out in the department of haematology of Hedi Chaker Hospital. Suspected invasive aspergillosis cases were reviewed and classified as proven, probable and possible invasive aspergillosis using the EORTC criteria. During the study period, we collected weekly environmental samples (patient's rooms, tables and acclimatisers) and clinical samples from each patient (nasal, expectoration and auricular). Among 105 neutropenic patients, 16 had probable and 13 had possible IA. A total of 1680 clinical samples were collected and A. flavus was most frequently isolated (79.2%). Analysis of 690 environmental samples revealed that Penicillium (44%) was the most frequent followed by Cladosporium (20%), Aspergillus spp. (18%) and Alternaria (13%). The PCR-sequencing of 30 A. flavus isolates detected from clinical and environmental samples confirmed the mycological identification. Our findings underline the importance of environmental surveillance and strict application of preventive measures.