Balamuthia mandrillaris is an opportunistic free-living amoeba that has been reported to cause skin lesions and the fatal Balamuthia amoebic encephalitis (BAE) in humans and other animals. Currently, around 200 human BAE cases have been reported worldwide, although this number is considered to be underestimated. The highest number of BAE cases has been reported in the American continent, mainly in the southwest of the USA. Peru seems to be another hotspot for BAE with around 55 human cases having been identified, usually involving cutaneous infection, especially lesions in the central face area. The isolation of Balamuthia from environmental sources has been reported on only three prior occasions, twice from Californian soils and once from dust in Iran and so it seems that this amoeba is relatively rarely encountered in samples from the environment. We investigated that possibility of finding the amoebae in soil samples from different regions where clinical cases have been reported in Peru. Twenty-one samples were cultured in non-nutrient agar plates and were checked for the presence of B. mandrillaris-like trophozoites and/or cysts. Those samples that were positive for these amoebae by microscopic criteria were then confirmed by PCR amplification and DNA sequencing of the mitochondrial 16S rDNA gene of B. mandrillaris. We have detected the presence of B. mandrillaris in four samples collected in the regions of Piura (3) and Lima (1) where infection cases have been previously reported. We hypothesize that B. mandrillaris is present in Peru in soil and dust which therefore constitutes a source of the infection for the BAE cases previously reported in this country. Further studies should be carried out in the area to confirm the generality of this finding.
Free-living Amoebae of Acanthamoeba genus include non-pathogenic and pathogenic strains that are currently classified in 18 different genotypes, T1-T18. In this study, a survey was carried out to evaluate the presence of Acanthamoeba strains in soil samples collected between 2012 and 2013 in Gran Canaria Island, Canary Islands, Spain. Samples were inoculated onto non-nutrient agar (NNA) plates and were checked for the presence of Acanthamoeba. Identification of Acanthamoeba strains was based on the morphology of the cyst and trophozoite forms. Subsequently, positive samples were cloned for their molecular characterization at the genotype level by sequencing the DF3 region located in the 18S rDNA gene of Acanthamoeba as previously described. Sequencing results revealed the presence of T2, T5 and T4 genotypes within the studied samples. To the best of our knowledge, this is the first report demonstrating the presence of Acanthamoeba in Gran Canaria Island and the first study at the genotype level in the Canary Islands.
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