Revisiting fecal metatranscriptomics analyses of macaques with idiopathic chronic diarrhoea with a focus on trichomonad parasites

Abstract

Trichomonads, anaerobic microbial eukaryotes members of the phylum Parabasalia, are common obligate extracellular symbionts that can lead to pathological or asymptomatic colonization of various mucosal surfaces in a wide range of animal hosts. Results from previous in vitro studies have suggested a number of intriguing mucosal colonization strategies by Trichomonads, notably highlighting the importance of interactions with bacteria. However, in vivo validation is currently lacking. A previous metatranscriptomics study into the cause of idiopathic chronic diarrhoea in macaques reported the presence of an unidentified protozoan parasite related to Trichomonas vaginalis. In this work, we performed a reanalysis of the published data in order to identify the parasite species present in the macaque gut. We also leveraged the information-rich metatranscriptomics data to investigate the parasite behaviour in vivo. Our results indicated the presence of at least 3 genera of Trichomonad parasite; Tetratrichomonas, Pentatrichomonas and Trichomitus, 2 of which had not been previously reported in the macaque gut. In addition, we identified common in vivo expression profiles shared amongst the Trichomonads. In agreement with previous findings for other Trichomonads, our results highlighted a relationship between Trichomonads and mucosal bacterial diversity which could be influential in health and disease.

Prevalence of intestinal trichomonads in captive non-human primates in China

“…( Table 1 ), and P. hominis and Tetratrichomonas sp. have previously been documented in NHPs [ 2 , 18 , 24 ]. Importantly, P. hominis has a wide range of hosts and has frequently been detected in many mammals including humans, highlighting its zoonotic potential [ 12 , 28 ].…”

Unraveling the pathogenic potential of the Pentatrichomonas hominis PHGD strain: impact on IPEC-J2 cell growth, adhesion, and gene expression

“…In the past, it was considered a symbiotic or conditionally pathogenic entity within the intestines of both humans and animals. However, recent studies have reported the presence of P. hominis in the feces of affected individuals and animals [ 2 , 3 , 6 , 24 ].…”

“…Experimental evidence has shown that one T. vaginalis TvBspA-like and two TvPmp-like proteins promoted interactions between T. vaginalis and vaginal epithelial cells. Additionally, Bailey and Hirt [ 2 ] emphasized the interplay between trichomonads and the mucosal bacteria, highlighting its impact on overall health. These parasitic entities engage in competition with the intestinal microflora for adhesion with the host’s epithelial cells.…”