Blastocystis and Clostridioides difficile: Evidence for a Synergistic Role in Colonization Among IBD Patients with Emphasis on Ulcerative Colitis

Abstract

Background: Regarding the controversial role of Blastocystis in inflammatory bowel diseases (IBD) patients, it seems that this protozoan

may lead to an overgrowth of some non-beneficial bacteria. The current study aimed to investigate the co-existence of Blastocystis and

Clostridioides difficile in IBD patients.

Methods: Stool samples of 102 IBD patients were collected and cultivated for C. difficile and Blastocystis. DNA extraction was performed

on positive samples and C. difficile and Blastocystis were toxinotyped and subtyped, respectively. Fisher’s exact test and logistic regression

were employed to calculate the correlation between the existence of Blastocystis and its subtypes (ST) with C. difficile and its type

of toxins. Also, the co-existence of Blastocystis and C. difficile with the frequency of defecations was evaluated.

Results: Blastocystis and C. difficile were observed in 17 (16.7%) and 26 (25.5%) of stool samples, respectively. From 26 C. difficilepositive

isolates, 24 (92.3%) and 2 (7.7%) were tcdA+/B+ and tcdA+/B-, respectively. Also, 10 (58.8%) and 7 (41.2%) were Blastocystis

ST1 and ST3, respectively. Statistically significant correlations between co-existence of Blastocystis and C. difficile and co-existence

of these microorganisms and frequency of defecation (P < .035) were seen. There was no statistically significant correlation between

subtypes of Blastocystis and colonization of C. difficile or its toxinotypes.

Conclusion: The co-existence of Blastocystis and C. difficile in IBD patients was observed in the current study. Moreover, it can be proposed

that these microorganisms may have synergistic effects on their colonization in the gastrointestinal tract.