Genetic analysis of forty isolates of Acanthamoeba Group III by multilocus isoenzyme electrophoresis

Two clinical and 32 environmental Acanthamoeba isolates belonging to Group III were compared with reference strains of A. culbertsoni, A. healyi, A. jacobsi, A. lenticulata, A. royreba and A. palestinensis by multilocus isozyme analysis. Genetically useful data were produced for 21 loci. The two principle clusters corresponded to A. jacobsi (20 isolates) and A. lenticulata (up to 9 isolates). A. jacobsi was the least variable species and was widely distributed, with isolates from Australia, Fiji, Japan, New Guinea, New Zealand and Britain. Most other isolates occurred as single zymodemes, not closely related to each other. No new isolate could be assigned to A. culbertsoni, A. healyi, or A. royreba. A clinical isolate from an Australian GAE case, AC 118, was the only 44°C-tolerant isolate not referable to A. jacobsi and appears to be a new species.