Recognition of Pathogenic Free-Living Amoebae in the Surface Water in Shiraz, Iran

Background: there are many genera of free-living amoeba inthe environment, but members of only four genera (naegleria,acanthamoeba, balamuthia and sappinia) have an associationwith human infection. water, soil and air are main sources ofinfective types of these pathogenic organisms for human.methods: totally, 30 samples were collected from the surfacewater sources of shiraz city, the capital of fars province,during july and august 2009. the samples were filtered andtheir sediments were cultured on non-nutrient agar medium andseeded with non-pathogen escherichia coli. then, they wereincubated at three different temperatures, 22?c, 37?c, and 44?c.the media were checked with invert microscopy and amoebaewere recognized by phase–contrast microscopy and observedby light microscopy after trichrome staining. polymerase chainreaction (pcr) was performed for molecular detection.results: of the 30 samples, 29 were recognized morphologically asacanthamoeba, the characteristics of 20 of which were confirmedby pcr. the growth rate of amoeba in 22?c was more than 37?c.eight of the samples grew at 44?c, but flagellate forming testand pcr were negative for naegleria fowleri. two of them wereidentified morphologically as balamuthia and sappinia.conclusion: since fars province is located in the subtropicalregion where there are a lot of parks and green areas with surfacewater, the potential risk of diseases caused by free-living amoebaeshould be considered. further investigations about various aspectsof these important opportunistic protozoa are recommendedespecially for establishment of appropriate prevention tools.