Mitochondrial DNA fingerprinting of Acanthamoeba spp. isolated from clinical and environmental sources

Restriction fragment length polymorphism analysis of mitochondrial DNA (mtDNA fingerprinting) was evaluated as an epidemiologic tool for identifying potential reservoirs of Acanthamoeba infection. Fingerprints for 15 clinical isolates recovered by our affiliated laboratories were compared with those for 25 environmental isolates from western Washington State and 10 American Type Culture Collection (ATCC) strains. Seven different fingerprint groups emerged from the analysis of clinical isolates with six selected restriction enzymes (BamHI, BglII, EcoRI, HindIII, KpnI, and SalI). Fourteen (56%) environmental and 4 (40%) ATCC isolates displayed fingerprints similar to those of clinical isolates. In all, five of the seven groups contained one or more environmental and/or ATCC isolates. Comparisons with published mtDNA fingerprints for Acanthamoeba isolates showed that two groups have counterparts in Europe and Japan and in Europe and Australia. The inclusion of environmental isolates demonstrated that the most common clinical isolates do have counterparts readily recoverable from the surrounding environment and that some of these counterparts appear to be geographically widespread.