Novel data from Italian Vermamoeba vermiformis isolates from multiple sources add to genetic diversity within the genus.

Vermamoeba vermiformis represents one of the most common free-living amoebae identified in worldwide environmental surveys. We analyzed 56 water samples with varying characteristics, including temperature and the particular settings in which humans may be exposed to water, plus one corneal scraping from a keratitis patient, with the following aims: (i) to investigate the presence of V. vermiformis; (ii) to identify the isolate subtypes; (iii) to place the Italian isolates in the broader picture of the genetic diversity within V. vermiformis. Twenty-two isolates were identified upon culturing and sequencing of > 600 bp in the 18S ribosomal RNA (rRNA) gene sequence, bringing to 27 the number of sequences recovered from Italian sources. By adding deposited sequences, we assembled a dataset of 74 isolates. Three of our isolates were characterized by allelic code 7-5-1-1, never reported before, and two showed 100% identity with an uncultured eukaryote and carried the 719T>C variant. We show that the variable segments E5, E3, F, and G convey most of the information on diversity, enabling the clustering of the isolates in a replicable fashion. The presence of different strains in natural thermal waters and in distribution systems indicated heterogeneity of the amoebic populations. Also, ours and the only other sequence from human infection were mapped in different clades. Overall, we enlarged the repertoire of single nucleotide and indel variants and the list of allelic codes, proceeding one step further in the description of the diversity within the genus.

Identification and phylogenetic position of Naegleria spp. from geothermal springs in Italy.

Naegleria spp. are free-living amoebae belonging to the family Vahlkampfiidae, in the class Heterolobosea. Among the recognized species, Naegleria fowleri causes primary amoebic meningoencephalitis (PAM), while two other species, Naegleria australiensis and Naegleria italica, have been reported as pathogenic in experimental animals. Due to the thermotolerance properties of some species, geothermal water sources including hot springs represent suitable habitats for their proliferation. The main aim of this study was a year-round sampling in two geothermal springs in Central Italy, to investigate the presence of Naegleria spp. using PCR/DNA sequencing based methods. The affinities between the sequences generated here and others reported in the literature were explored by using POY, which implements the concept of dynamic homology. Naegleria australiensis, Naegleria italica, and Naegleria lovaniensis, plus an unassigned Naegleria spp. were detected. Indels in the rDNA ITS1 and ITS2 turned out to be critical to distinguish the three species and confirmed their phylogenetic relationships. This is the first molecular report on the Naegleria spp. occurrence in geothermal waters in Central Italy, coupled with a fine genetic characterization.

Molecular identification of Mesocestoides sp. metacestodes in a captive gold-handed tamarin (Saguinus midas).

Mesocestoides spp. are tapeworms harbored in the intestine of many domestic and wild carnivores, birds of prey and, rarely, of humans. The life cycle is assumed to involve three hosts and the metacestode juvenile stage (tetrathyridium) may reproduce asexually, provoking severe systemic infections. In the present study, a case of a peritoneal infection by Mesocestoides sp. occurred in a captive gold-handed tamarin (Saguinus midas) is described. Phylogenetic positions based on CO1 and 12S loci were analysed to describe in details this unusual finding of Mesocestoides in a callitrichid monkey. The phylogenetic analyses has not clearly resolve relationships between the metacestode forms from the tamarin and any of the described Mesocestoides species available so far, including those described from non-human primates, thus supporting the hypothesis of a new taxon within the genus.