[Pathogenic properties of free-living amoebae isolated from natural and man-made bathing sites in the province of Western Pomerania].

INTRODUCTION: Pathogenic amoebae belonging to the genus of Acanthamoeba and Naegleria, as well as species such as Balamuthia mandrillaris and Sappinia diploidea cause harmful, life-threatening infections in humans and animals. These amoebae commonly occur in the natural environment. Free-living, pathogenic amoebae have hitherto been detected in water reservoirs near Poznań, Gdańsk, and Lublin.

MATERIAL AND METHODS: The present work focused on the occurrence of thermophilic amoebae potentially pathogenic to humans. Natural and man-made bathing sites in the province of Western Pomerania were studied. A total of 299 water samples were collected between 2001 and 2003 from 86 sites (indoor swimming pools, seasonal pools, physiotherapy pool, fountains, lakes, ponds, rivers, lagoons, and coastal waters of the Baltic Sea). Amoebae were isolated at 37 degrees C from 223 samples, of which 34 (15.2%) demonstrated thermophilic properties. Tests using thermophilic isolates were carried out on mice through intranasal inoculation. Pathogenic properties and intensity of infection were determined on the basis of re-isolation of amoebae from agar substrates inoculated with fragments of internal organs. Organs of infected mice were examined histologically.

RESULTS: Six isolates exhibited infective properties in mice. Five of them were obtained from two man-made water reservoirs belonging to the recreational complex of the city of Szczecin (AM 17, AM 148, AD 16, AD 148, AD 166). One isolate was from a natural reservoir (JG 172). Amoebae were isolated from the brain, lungs, liver, kidneys, spleen, and heart of the infected animals.