The taxonomic situation in the genus Tritrichomonas is
the
subject of controversial discussion: potentially T. foetus and
T. suis, the tritrichomonads from cattle and swine, respectively,
could belong to the same species. In order to shed some
light on this question, a molecular biological analysis was performed.
The
5·8S rRNA gene and the flanking internal
transcribed spacer regions (ITS1 and ITS2) of 12 different isolates of
3
Tritrichomonas species T. foetus, T. suis and
T.
mobilensis were enzymatically amplified by PCR and subcloned. Also,
the
corresponding regions of the trichomonads
Trichomonas vaginalis, T. tenax, T. gallinae
and
Pentatrichomonas hominis were included in this study. Sequence
analysis
of cloned fragments was used to compare the parasite isolates. The genus
Tritrichomonas exhibited an extremely high
degree of homogeneity. All T. foetus and T. suis isolates
had identical sequences, and only 1 substitution was found in the
ITS2 region of T. mobilensis. In contrast, the genus Trichomonas
shared more diversity. The results obtained in this study
support a possible future revision of the taxonomic classification of
tritrichomonads.