Molecular Evidence for Greater Diversity Within Acanthamoeba.

PURPOSE

The opportunistic parasite Acanthamoeba comprises several genotypes. However, partial rDNA sequences and previous work suggest the possible existence of other, as yet unrecorded lineages. This study aims to identify such sequences and clarify their relationships.

METHODS

In this study, a broad search for possible new rDNA sequences belonging to Acanthamoeba and its closest relatives was conducted by exploring available data in GenBank.

RESULTS

Several partial sequences, including 18S and/or LSU rDNA sequences, were identified, representing additional genotypes within the Acanthamoeba culbertsoni and Acanthamoeba micheli groups, as well as entirely new near-basal lineages for which no morphological data are available. Furthermore, some sequences could belong to new species of Protacanthamoeba, Luapeleamoeba, and/or a close relative within Acanthamoebidae.

CONCLUSION

The study identified several highly divergent partial 18 S/LSU rDNA sequences that branch consistently in phylogenetic trees and likely represent new lineages. Given the increasing diversity of Acanthamoeba and its close relatives, further efforts to isolate these strains for morphological study are recommended.