Clinical Significance and Subtype Distribution of Blastocystis Infection with Colonoscopy Findings
-
Erdogan Malatyali
,
Ismail Taskiran
,
Levent Durmus Guler
,
Adil Coskun
,
Evren Tileklioglu
,
Hatice Ertabaklar
,
ibrahim Yıldız
,
Sema Ertug
Abstract
Background: As the role of Blastocystis in the pathogenesis of intestinal disorders remains controversial, we aimed to clarify its clinical significance and subtype (ST) distribution in relation to colonoscopic findings.
Methods: Fecal samples were collected from adult patients scheduled for colonoscopy in Aydin Adnan Menderes University, Gastroenterology Department in 2023, 125 consecutive patients with colonic abnormalities and 125 with normal mucosa. Blastocystis positivity was determined with direct microscopy and amplification of the small subunit ribosomal RNA (SSU rRNA) gene. Subtypes were determined based on exact database matches. Demographic characteristics and clinical findings of participants were statistically analyzed.
Results: Blastocystis was detected in 26 fecal samples (10.4%) by direct microscopy and 32 samples (12.8%) by molecular test. Positivity was 16.0% (n=20) in controls and 9.6% (n=12) in patients with colonic abnormalities, with no significant difference (P>0.05). In males, Blastocystis was more prevalent in those with normal findings than with abnormalities (n=11, 19.6% vs. n=6, 7.7%, P<0.05), whereas no difference was observed in females (P>0.05). Subtype distribution was ST3 (59.4%, n=19), ST2 (21.8%, n=7), and ST1 (18.7%, n=6). No significant association was found between the overall Blastocystis positivity and age, gender, or gastrointestinal symptoms.
Conclusion: Although limited to routine colonoscopic findings, these results raise questions about the potential association of Blastocystis with a healthy gut or colonic abnormalities. ST3 was the predominant subtype, consistent with national and global reports.
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2. Pipatsatitpong D, Leelayoova S, Mungthin M, et al. Prevalence and Risk Factors for Blastocystis Infection Among Children and Caregivers in a Child Care Center, Bangkok, Thailand. Am J Trop Med Hyg. 2015;93(2):310-5.
3. Wawrzyniak I, Poirier P, Viscogliosi E, et al. Blastocystis, an unrecognized parasite: an overview of pathogenesis and diagnosis. Ther Adv Infect Dis. 2013;1(5):167-78.
4. Sejnohova A, Koutenska M, Jirku M, et al. A cross-sectional survey of Blastocystis sp. and Dientamoeba fragilis in non-human primates and their caregivers in Czech zoos. One Health. 2024; 19:100862.
5. Rauff-Adedotun AA, Meor Termizi FH, Shaari N, et al. The Coexistence of Blastocystis spp. in Humans, Animals and Environmental Sources from 2010–2021 in Asia. Biology (Basel). 2021; 10(10):990.
6. Tan KS, Mirza H, Teo JD, et al. Current Views on the clinical relevance of Blastocystis spp. Curr Infect Dis Rep. 2010;12(1):28-35.
7. Coskun A, Malatyali E, Ertabaklar H, et al. Blastocystis in ulcerative colitis patients: Genetic diversity and analysis of laboratory findings. Asian Pac J Trop Med. 2016;9(9):916-9.
8. Ragavan ND, Kumar S, Chye TT, Mahadeva S, et al. Blastocystis sp. in irritable bowel syndrome (IBS)-detection in stool aspirates during colonoscopy. PLoS One. 2015;10(9):e0121173.
9. Hong SM, Baek DH. A review of colonoscopy in intestinal diseases. Diagnostics (Basel). 2023;13(7): 1262.
10. Yoshikawa H, Wu Z, Nagano I, et al. Molecular comparative studies among Blastocystis isolates obtained from humans and animals. J Parasitol. 2003;89(3):585-594.
11. Piperni E, Nguyen LH, Manghi P, et al. Intestinal Blastocystis is linked to healthier diets and more favorable cardiometabolic outcomes in 56,989 individuals from 32 countries. Cell. 2024;187(17):4554- 4570.e18.
12. Issa YA, Ooda SA, Salem AI, et al Molecular diagnosis and subtyping of Blastocystis sp.: Association with clinical, colonoscopic, and histopathological findings. Trop Parasitol. 2023;13(1):46-53.
13. Sulzyc-Bielicka V, Kolodziejczyk L, Adamska M, et al. Colorectal cancer and Blastocystis sp. infection. Parasit Vectors. 2021;14(1):200.
14. Kumarasamy V, Atroosh WM, Anbazhagan D, et al. Association of Blastocystis hominis with colorectal cancer: A systematic review of in vitro and in vivo evidences. World J Gastrointest Oncol. 2022;14(3):734-45.
15. Labania L, Zoughbor S, Ajab S, et al. The associated risk of Blastocystis infection in cancer: A case control study. Front Oncol. 2023; 13:1115835.
16. Toychiev A, Abdujapparov S, Imamov A, et al. Intestinal helminths and protozoan infections in patients with colorectal cancer: prevalence and possible association with cancer pathogenesis. Parasitol Res. 2018;117(12):3715-23.
17. Yakoob J, Abbas Z, Usman MW, et al. Cytokine changes in colonic mucosa associated with Blastocystis spp. subtypes 1 and 3 in diarrhoea-predominant irritable bowel syndrome. Parasitology. 2014;141(7):957-69.
18. Tocci S, Das S, Sayed IM. An Update on Blastocystis: Possible Mechanisms of Blastocystis-Mediated Colorectal Cancer. Microorganisms. 2024; 12(9):1924.
19. Krogsgaard LR, Engsbro AL, Stensvold CR, et al. The prevalence of intestinal parasites is not greater among individuals with irritable bowel syndrome: a population-based case-control study. Clin Gastroenterol Hepatol. 2015;13(3):507-513.e2.
20. Rossen NG, Bart A, Verhaar N, et al. Low prevalence of Blastocystis sp. in active ulcerative colitis patients. Eur J Clin Microbiol Infect Dis. 2015;34(5):1039-44.
21. Kim M-J, Won EJ, Kim SH, et al. Molecular detection and subtyping of human Blastocystis and the clinical implications: Comparisons between diarrheal and non-diarrheal groups in Korean populations. Korean J Parasitol. 2020;58(3):321-326.
22. Lucia JF, Aguilar C, Betran A. Blastocystis hominis colitis in a haemophilic patient as a cause of lower gastrointestinal bleeding. Haemophilia. 2007;13(2):224-5.
23. Tsaousis AD, Shaw D, Jirku K, et al. Rethinking Blastocystis: ubiquity and cyclical abundance in the human gut. Trends Parasitol. 2025;41(11):954-958.
24. Malatyali E, Ertabaklar H, Ertug S. Subtype Distribution of Blastocystis spp. with DNA Barcoding and Evaluation of Diagnostic Methods. Mikrobiyol Bul. 2019;53(3):308-18.
25. Popruk S, Adao DEV, Rivera WL. Epidemiology and subtype distribution of Blastocystis in humans: A review. Infect Genet Evol.2021;95:105085.
26. Jimenez P, Munoz M, Ramirez JD. An update on the distribution of Blastocystis subtypes in the Americas. Heliyon. 2022;8(12):e12592.
27. Maleki B, Olfatifar M, Dodangeh S, et l. Subtype distribution of Blastocystis sp. isolated from humans in Iran: a systematic review and meta-analysis. Gastroenterol Hepatol Bed Bench. 2022;15(4):294-310.
28. Mattiucci S, Crisafi B, Gabrielli S, et al. Molecular epidemiology and genetic diversity of Blastocystis infection in humans in Italy. Epidemiol Infect. 2016;144(3):635-46.
29. Yan Y, Su S, Lai R, et al. Genetic variability of Blastocystis hominis isolates in China. Parasitol Res. 2006;99(5):597-601.
30. Malheiros AF, Stensvold RC, Clark GC, et al. Short Report: Molecular characterization of Blastocystis obtained from members of the indigenous Tapirapé Ethnic Group from the Brazilian Amazon Region, Brazil. Am J Trop Med Hyg. 2011;85(6):1050-3.
31. Khaled S, Gantois N, Ly AT, et al. Prevalence and subtype distribution of blastocystis sp. in Senegalese school children. Microorganisms. 2020; 8(9):1408.
32. Khoshnood S, Rafiei A, Saki J, et al. Prevalence and Genotype Characterization of Blastocystis hominis Among the Baghmalek People in Southwestern Iran in 2013-2014. Jundishapur J Microbiol. 2015;8(10):e23930.
33. Salehi M, Mardaneh J, Niazkar HR, et al. Prevalence and subtype analysis of Blastocystis hominis isolated from patients in the northeast of Iran. J Parasitol Res. 2021; 2021:8821885.
34. Salazar-Sanchez RS, Ascuna-Durand K, Ballon-Echegaray J, et al. Socio-Demographic Determinants Associated with Blastocystis Infection in Arequipa, Peru. Am J Trop Med Hyg. 2020;104(2):700-7.
2. Pipatsatitpong D, Leelayoova S, Mungthin M, et al. Prevalence and Risk Factors for Blastocystis Infection Among Children and Caregivers in a Child Care Center, Bangkok, Thailand. Am J Trop Med Hyg. 2015;93(2):310-5.
3. Wawrzyniak I, Poirier P, Viscogliosi E, et al. Blastocystis, an unrecognized parasite: an overview of pathogenesis and diagnosis. Ther Adv Infect Dis. 2013;1(5):167-78.
4. Sejnohova A, Koutenska M, Jirku M, et al. A cross-sectional survey of Blastocystis sp. and Dientamoeba fragilis in non-human primates and their caregivers in Czech zoos. One Health. 2024; 19:100862.
5. Rauff-Adedotun AA, Meor Termizi FH, Shaari N, et al. The Coexistence of Blastocystis spp. in Humans, Animals and Environmental Sources from 2010–2021 in Asia. Biology (Basel). 2021; 10(10):990.
6. Tan KS, Mirza H, Teo JD, et al. Current Views on the clinical relevance of Blastocystis spp. Curr Infect Dis Rep. 2010;12(1):28-35.
7. Coskun A, Malatyali E, Ertabaklar H, et al. Blastocystis in ulcerative colitis patients: Genetic diversity and analysis of laboratory findings. Asian Pac J Trop Med. 2016;9(9):916-9.
8. Ragavan ND, Kumar S, Chye TT, Mahadeva S, et al. Blastocystis sp. in irritable bowel syndrome (IBS)-detection in stool aspirates during colonoscopy. PLoS One. 2015;10(9):e0121173.
9. Hong SM, Baek DH. A review of colonoscopy in intestinal diseases. Diagnostics (Basel). 2023;13(7): 1262.
10. Yoshikawa H, Wu Z, Nagano I, et al. Molecular comparative studies among Blastocystis isolates obtained from humans and animals. J Parasitol. 2003;89(3):585-594.
11. Piperni E, Nguyen LH, Manghi P, et al. Intestinal Blastocystis is linked to healthier diets and more favorable cardiometabolic outcomes in 56,989 individuals from 32 countries. Cell. 2024;187(17):4554- 4570.e18.
12. Issa YA, Ooda SA, Salem AI, et al Molecular diagnosis and subtyping of Blastocystis sp.: Association with clinical, colonoscopic, and histopathological findings. Trop Parasitol. 2023;13(1):46-53.
13. Sulzyc-Bielicka V, Kolodziejczyk L, Adamska M, et al. Colorectal cancer and Blastocystis sp. infection. Parasit Vectors. 2021;14(1):200.
14. Kumarasamy V, Atroosh WM, Anbazhagan D, et al. Association of Blastocystis hominis with colorectal cancer: A systematic review of in vitro and in vivo evidences. World J Gastrointest Oncol. 2022;14(3):734-45.
15. Labania L, Zoughbor S, Ajab S, et al. The associated risk of Blastocystis infection in cancer: A case control study. Front Oncol. 2023; 13:1115835.
16. Toychiev A, Abdujapparov S, Imamov A, et al. Intestinal helminths and protozoan infections in patients with colorectal cancer: prevalence and possible association with cancer pathogenesis. Parasitol Res. 2018;117(12):3715-23.
17. Yakoob J, Abbas Z, Usman MW, et al. Cytokine changes in colonic mucosa associated with Blastocystis spp. subtypes 1 and 3 in diarrhoea-predominant irritable bowel syndrome. Parasitology. 2014;141(7):957-69.
18. Tocci S, Das S, Sayed IM. An Update on Blastocystis: Possible Mechanisms of Blastocystis-Mediated Colorectal Cancer. Microorganisms. 2024; 12(9):1924.
19. Krogsgaard LR, Engsbro AL, Stensvold CR, et al. The prevalence of intestinal parasites is not greater among individuals with irritable bowel syndrome: a population-based case-control study. Clin Gastroenterol Hepatol. 2015;13(3):507-513.e2.
20. Rossen NG, Bart A, Verhaar N, et al. Low prevalence of Blastocystis sp. in active ulcerative colitis patients. Eur J Clin Microbiol Infect Dis. 2015;34(5):1039-44.
21. Kim M-J, Won EJ, Kim SH, et al. Molecular detection and subtyping of human Blastocystis and the clinical implications: Comparisons between diarrheal and non-diarrheal groups in Korean populations. Korean J Parasitol. 2020;58(3):321-326.
22. Lucia JF, Aguilar C, Betran A. Blastocystis hominis colitis in a haemophilic patient as a cause of lower gastrointestinal bleeding. Haemophilia. 2007;13(2):224-5.
23. Tsaousis AD, Shaw D, Jirku K, et al. Rethinking Blastocystis: ubiquity and cyclical abundance in the human gut. Trends Parasitol. 2025;41(11):954-958.
24. Malatyali E, Ertabaklar H, Ertug S. Subtype Distribution of Blastocystis spp. with DNA Barcoding and Evaluation of Diagnostic Methods. Mikrobiyol Bul. 2019;53(3):308-18.
25. Popruk S, Adao DEV, Rivera WL. Epidemiology and subtype distribution of Blastocystis in humans: A review. Infect Genet Evol.2021;95:105085.
26. Jimenez P, Munoz M, Ramirez JD. An update on the distribution of Blastocystis subtypes in the Americas. Heliyon. 2022;8(12):e12592.
27. Maleki B, Olfatifar M, Dodangeh S, et l. Subtype distribution of Blastocystis sp. isolated from humans in Iran: a systematic review and meta-analysis. Gastroenterol Hepatol Bed Bench. 2022;15(4):294-310.
28. Mattiucci S, Crisafi B, Gabrielli S, et al. Molecular epidemiology and genetic diversity of Blastocystis infection in humans in Italy. Epidemiol Infect. 2016;144(3):635-46.
29. Yan Y, Su S, Lai R, et al. Genetic variability of Blastocystis hominis isolates in China. Parasitol Res. 2006;99(5):597-601.
30. Malheiros AF, Stensvold RC, Clark GC, et al. Short Report: Molecular characterization of Blastocystis obtained from members of the indigenous Tapirapé Ethnic Group from the Brazilian Amazon Region, Brazil. Am J Trop Med Hyg. 2011;85(6):1050-3.
31. Khaled S, Gantois N, Ly AT, et al. Prevalence and subtype distribution of blastocystis sp. in Senegalese school children. Microorganisms. 2020; 8(9):1408.
32. Khoshnood S, Rafiei A, Saki J, et al. Prevalence and Genotype Characterization of Blastocystis hominis Among the Baghmalek People in Southwestern Iran in 2013-2014. Jundishapur J Microbiol. 2015;8(10):e23930.
33. Salehi M, Mardaneh J, Niazkar HR, et al. Prevalence and subtype analysis of Blastocystis hominis isolated from patients in the northeast of Iran. J Parasitol Res. 2021; 2021:8821885.
34. Salazar-Sanchez RS, Ascuna-Durand K, Ballon-Echegaray J, et al. Socio-Demographic Determinants Associated with Blastocystis Infection in Arequipa, Peru. Am J Trop Med Hyg. 2020;104(2):700-7.
| Files | ||
| Issue | Vol 21 No 2 (2026) | |
| Section | Original Article(s) | |
| Keywords | ||
| Blastocystis Colonoscopy Subtype Clinical findings | ||
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How to Cite
1.
Malatyali E, Taskiran I, Guler L, Coskun A, Tileklioglu E, Ertabaklar H, Yıldız ibrahim, Ertug S. Clinical Significance and Subtype Distribution of Blastocystis Infection with Colonoscopy Findings. Iran J Parasitol. 2026;21(2):164-173.
