Freezing of faeces dramatically decreases the viability of Blastocystis sp. and Dientamoeba fragilis

Abstract

We recorded a positive culture of Blastocystis in one of five frozen replicates, consistent with its previously reported transmissibility. Given the unclear pathogenicity of Blastocystis and Dientamoeba in parallel with our results of deep freezing, which seriously compromise the viability of both protists, a discussion on the current FMT recommendation should be opened.

Furthermore, if future studies confirm the safety of frozen-thawed FMT, the practice of excluding donors positive for Blastocystis sp., D. fragilis or both should be revised.

Keywords

• Blastocystis
• Dientamoeba fragilis
• Faecal microbiota transplantation