The role of Blastocystis sp. as an etiology of irritable bowel syndrome

Abstract

Blastocystis is a common intestinal protozoan of humans and animals. The role of this organism as a pathogen is still controversial. The Blastocystis infection could be asymptomatic or could include nausea, anorexia, abdominal pain, flatulence, and/or diarrhea. An association between Blastocystis infection and acute chronic digestive disorders such as irritable bowel syndrome (IBS) have also been suggested. In this article, the evidence concerning Blastocystis infection causing IBS will be discussed, with regard to the subtypes of the parasite. An association between the parasite and IBS has been suggested in the recent literature. The explanations of pathogenicity include an intra-subtype difference (ST4 and ST7) with regard to protease activity during infection with Blastocystis. It is most likely that the presence of Blastocystis in the human intestine plays a significant role in IBS. On the other hand, it is still not known if Blastocystis is the etiological agent responsible for this type of gut dysfunction. There are many reports in the literature which are mutually exclusive. More studies are needed to confirm this hypothesis.