[Isolation of potencially pathogenic free-living amoebas in hospital dust].

OBJECTIVE To evaluate the occurrence of free-living amoebas of the genera Acanthamoeba and Naegleria is dust samples colleted in two hospitals. METHODS One-hundred and thirty-two dust samples were collected in two hospitals in Brazil. Hospital collection sites were the following: intensive care unit, operation rooms, nursery, kitchen, emergency and infectious diseases isolation room. The isolation of the amoebas was performed in three culture media: non-nutrient agar inoculated with Escherichia coli, soy agar, and microculture in Giazzi-modified Pavlova's medium. The amoebas were identified according to morphological criteria. RESULTS Amoebas of the genera Acanthamoeba and Naegleria were found in 45.5% of the samples, of which 41.6% were collected in the university hospital and 50% in the state hospital. Of all, 45.5% were positive for the genera Acanthamoeba and 3.8% for genera Naegleria. CONCLUSIONS Potentially pathogenic free-living amoebas were seen in all sites of the two hospitals and Acanthamoeba was the most frequently isolated genera.