First report of vannellidae amoebae (vannella spp.) isolated from biofilm source

Members of the Vannellidae family are free-living amoebae (FLA) distributed mainly in water and soil sources. The present study reports the first isolation of this genus in the biofilm source from hospital environment in Tehran, Iran.

Biofilm samples were collected from hospital environment. Cultivation was performed in non-nutrient agar covered with a heat-killed Escherichia coli. Cloning of the suspected amoebae was done. PCR amplification and Homology analysis using the Basic Local Alignment Search Tool (BLASTn) was performed to search for the most similar reference sequences.

Microscopic examination showed numerous fan-shaped amoebae and peculiar cysts different to the usual shape of typical FLA. Sequence analysis of the PCR- product revealed that the suspected amoebae are highly homologous with Vannella spp. gene (99% identity and 100% query coverage) available in the gene bank database.

Although Vannella spp. is not proved to be pathogenic itself, but they are capable of harboring pathogenic intracellular organisms such as Microsporidian parasites. Thus, identification of such amoebae can be of clinical importance, as they could lead to transmission of other pathogens to human.