Isolation and identification of pathogenic Naegleria australiensis (Amoebida, Vahlkampfiidae) from a spa in northern Italy

Samples from therapeutic swimming pools and mud basins were cultured for free-living amoebae. Seven strains of pathogenic Naegleria species were isolated. Although some of the strains were as virulent as Naegleria fowleri, the etiological agent of primary amoebic meningoencephalitis, they were identified as Naegleria australiensis with the indirect fluorescent-antibody technique. The virulence of the isolates for mice corresponded with the cytopathic effect for Vero cells. The N. australiensis strains were isolated from swimming pools with water temperatures ranging from 32 to 35 degrees C and from mud with temperatures from 25 to 43 degrees C. The presence of pathogenic N. australiensis in the swimming pools did not correlate with bacterial indicators.