The interplay between Blastocystis and human gut microbiota.

Gut microbiota, consisting of multiple beneficial microorganisms, significantly impacts host health. Recent investigations have revealed that the gut microbiota influences the pathogenicity of eukaryotes such as Blastocystis, and conversely, the protist can impact the composition of the bacterial community. This review focuses on both, beneficial and adverse interactions between Blastocystis and human gut microbiota communities. Blastocystis can modulate both the structure and composition of the gut microbiota. Research has demonstrated that Blastocystis colonization is associated with increased gut microbiota diversity, a higher abundance of beneficial bacteria like Firmicutes and Clostridiales, and reduced Bacteroides, indicating a potential beneficial relation. However, its exact role is still unknown, and it may be associated with dysbiosis in some gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Moreover, some researchers presented the contradictory study results of interactions between specific Blastocystis subtypes and gut bacteria. The bidirectional influence between microorganisms is complex, with distinct subtypes that can display varying effects on the microbiota. These discrepant findings might reflect variations in the host factors, microbial environment, or strain-level diversity.