title: Determination of internal transcribed spacer regions (ITS) in Trichomonas vaginalis isolates and differentiation among Trichomonas species.
abstract: The nucleotide sequence of the 5.8S rRNA gene and the flanked internal transcribed spacer (ITS) regions of six Trichomonas vaginalis isolates with different metronidazole sensitivity and geographic origin were genotyped. A multiple sequence alignment was performed with different sequences of other isolates available at the GenBank/EMBL/DDBJ databases, which revealed 5 different sequence patterns. Although a stable mutation in position 66 of the ITS1 (C66T) was observed in 26% (9/34) of the T. vaginalis sequences analyzed, there was 99.7% ITS nucleotide sequence identity among isolates for this sequence. The nucleotide sequence variation among other species of the genus Trichomonas ranged from 3.4% to 9.1%. Surprisingly, the % identity between T. vaginalis and Pentatrichomonas hominis was ~83%. There was >40% divergence in the ITS sequence between T. vaginalis and Tritrichomonas spp., including Tritrichomonas augusta, Tritrichomonas muris, and Tritrichomonas nonconforma and with Tetratrichomonas prowazeki. Dendrograms grouped the trichomonadid sequences in robust clades according to their genera. The absence of nucleotide divergence in the hypervariable ITS regions between T. vaginalis isolates suggests the early divergence of the parasite. Importantly, these data show this ITS1-5.8S rRNA-ITS2 region suitable for inter-species differentiation.
authors.affiliation: CEI Campus Moncloa, UCM-UPM and CSIC, Madrid, Spain; Departamento de Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain. Electronic address: alexandraibanez@ucm.es.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ibáñez-Escribano
authors.affiliation: CEI Campus Moncloa, UCM-UPM and CSIC, Madrid, Spain; Departamento de Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Nogal-Ruiz
authors.affiliation: CEI Campus Moncloa, UCM-UPM and CSIC, Madrid, Spain; Instituto de Química Médica (IQM), Spanish National Research Council (CSIC), C/Juan de la Cierva no 3, 28006 Madrid, Spain.
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Arán
authors.affiliation: CEI Campus Moncloa, UCM-UPM and CSIC, Madrid, Spain; Departamento de Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Escario
authors.affiliation: CEI Campus Moncloa, UCM-UPM and CSIC, Madrid, Spain; Departamento de Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Gómez-Barrio
authors.affiliation: School of Molecular Bioscience, College of Veterinary Medicine, Washington State University, Pullman WA, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Alderete
mesh_terms: D000818:Animals; D001483:Base Sequence; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D010802:Phylogeny; D016415:Sequence Alignment; D013045:Species Specificity; D014246:Trichomonas vaginalis / Q000235:genetics*
chemical_list: D021903:DNA, Ribosomal Spacer
keywords: Clades; Internal transcribed spacers (ITS); Phylogenetic study; Protozoa; Trichomonas vaginalis; rDNA