Pentatrichomonas hominis: first isolation from the feces of a dog with diarrhea in China

Abstract

A trichomonad-like parasite isolated from canine fecal samples in Changchun, China was successfully cultivated in vitro using RPMI1640 medium supplemented with 10% heat-inactivated calf serum and antibiotics. These were then subjected to scanning and transmission electron microscopy for ultrastructural study. This parasite has four anterior flagella of unequal length, one independent flagellum, and one recurrent flagellum. It exhibits an anterior nucleus, a Golgi complex, an axostyle, food vacuoles, and hydrogenosomes. These features are consistent with the ultrastructural characteristics of previously described Pentatrichomonas hominis. Polymerase chain reaction and sequence analysis of three genetic loci, including ITS1-5.8S rRNA-ITS2, 18S rRNA, and EF-1α, were also used to compare these samples with other trichomonad species. Molecular identification was also consistent with P. hominis. This is the first time that isolation of P. hominis has been isolated from dog in China, although several other strains of P. hominis have been isolated from human samples.

Co-infection by Tritrichomonas foetus and Pentatrichomonas hominis in asymptomatic cats

“…According to the results obtained on the morphology, small differences in the size and shape of the analyzed T. foetus trophozoites and to other morphological studies may be related with the medium used, cultivation time or fixing methods, or even with bacteria present in the medium (Kirby 1951, Tachezy et al 2002, Clothier et al 2015. The trophozoites of T. foetus show consistently three anterior flagella, unlike P. hominis which presents five flagella (Li et al 2014b). This is one of the features which can be used to differentiate among species (Kirby 1951).…”

Prevalence and Molecular Characterization of Intestinal Trichomonads in Pet Dogs in East China

“…Trichomonads consist of both pathogenic and presumably non-pathogenic species and are frequently encountered in veterinary medicine [ 1 , 2 ]. These single-celled obligate organisms are characterized morphologically by multiple anterior flagella and a single recurrent flagellum that functions as an undulating membrane [ 3 ].…”

“…These single-celled obligate organisms are characterized morphologically by multiple anterior flagella and a single recurrent flagellum that functions as an undulating membrane [ 3 ]. They commonly inhabit warm, moist, anaerobic locations within the gastrointestinal and genitourinary tracts of a variety of vertebrate and invertebrate hosts [ 2 , 4 , 5 ]. Two trichomonad species found in dogs have received scientific attention, Tritrichomonas foetus (family Tritrichomonadidae) and Pentatrichomonas hominis (family Trichomonadidae) [ 1 , 2 , 6 – 10 ].…”

“…In contrast, P. hominis has frequently been reported in dogs [ 1 , 2 , 6 – 10 ] and is presumed to be a commensal organism that may overgrow opportunistically in dogs with diarrhea from other causes [ 1 , 2 ]. However, several authors have described P. hominis as the probable causative agent of gastrointestinal disturbances in children [ 16 , 17 ], and this protozoan has also been found occasionally outside its natural habitat, in patients with liver abscesses [ 18 ] or empyema thoracis [ 9 , 19 ].…”

“…Unfortunately, few data are available on the epidemiology of trichomonads in pets in China. Recently, our laboratory identified P. hominis infections in dogs [ 2 ] and investigated their prevalence in dogs in northeast China [ 10 ]. Given China’s vast territory, the occurrence of the parasite may vary greatly in different regions.…”