[The surveillance of the aeraulic and hydraulic system reduce environmental Aspergillus contamination in hospital].

The aim of this work was to value the evolution of environmental Aspergillus contamination in hospital with respect to aeraulic system and bathrooms works. An analysis on levels of air and surface Aspergillus contamination were determined in patient's rooms and various common sites in a ward of an hospital in Genoa in 1999. As high contamination levels were found, in summer 1999 a radical disinfection and revision of the aeraulic system was settled. In spite of these interventions some samples maintained an high contamination level, even if from only two rooms, so a further disinfection of bathrooms and surfaces became necessary. A period of sampling was conducted after this last intervention until November 2002. At the beginning of our surveillance 59% positive samples and about 50% of them with high contamination level (>1000 CFU/m3) were found. After the revision of the aeraulic system the reduction of positive samples was significative (14.2%), besides all the positive samples regarded only two rooms. In the last valuation period, after a further disinfection of bathrooms and surfaces of the above mentioned rooms, all the samples taken resulted with a contamination level lower than 10 CFU/m3. This findings underlines the importance of environmental surveillance looking for all the contaminated sources; in particular the aeraulic and hydraulic system as well as the proximity hospital building yard not sufficiently protected.