Molecular Detection and Subtype Characterization of Blastocystis spp. in Symptomatic Children Using PCR and Sequencing
-
Samaneh Boulaghi
,
Amirali Reihani
,
BiBi Razieh Hosseini Farash
,
Yousef Sharifi
,
Omid Ahmadi
,
Alireza Samadi
,
Ghodratollah Salehi Sangani
,
Mohsen Najjari
,
Fariba Berenji
,
Mehdi Zarean
Abstract
Background: Blastocystis spp. is a globally distributed intestinal protozoan that infects humans and various animals. This protozoan is a common pathogen among humans and animals and can be transmitted from animal species to humans. Therefore, the present study aimed to identify and characterize Blastocystis subtypes in children with gastrointestinal symptoms using PCR and sequencing.
Methods: Overall, 150 stool samples were collected from children referred to academic hospitals in Mashhad, Iran over a period of seven months in 2020. Participants were divided into two groups: symptomatic cases (n = 50) and asymptomatic controls (n = 100). DNA was extracted from Blastocystis-positive samples and analyzed by PCR followed by sequencing for subtype identification.
Results: Blastocystis spp. was found in 6 (12%) of the symptomatic children and 7 (7%) of the asymptomatic group. All isolates from symptomatic cases belonged to subtype ST1, whereas isolates from the control group included ST1, ST2, ST3, and ST7. ST1 was the most frequently detected subtype overall. Among symptomatic children, abdominal pain was the most frequent symptom.
Conclusion: ST1 was the predominant subtype in both symptomatic and asymptomatic children, though it was the only subtype observed in symptomatic cases. These findings suggest a potential link between ST1 and gastrointestinal symptoms. Further studies with larger populations and in diverse geographic regions are warranted to investigate the clinical significance and distribution patterns of Blastocystis subtypes.
1. Xu N, Jiang Z, Liu H, et al. Prevalence and genetic characteristics of Blastocystis hominis and Cystoisospora belli in HIV/AIDS patients in Guangxi Zhuang Autonomous Region, China. Sci Rep. 2021;11(1):15904.
2. Alexeieff A. Sur la nature des formations dites kystes de Trichomonas intestinalis. CR Soc Biol. 1911;71:296-8.
3. Villalobos G, López-Escamilla E, Olivo-Díaz A, et al. Genetic Variation among the Partial Gene Sequences of the Ribosomal Protein Large-Two, the Internal Transcribed Spacer, and the Small Ribosomal Subunit of Blastocystis sp. from Human Fecal Samples. Microorganisms. 2024; 12(6):1152.
4. Valença-Barbosa C, do Bomfim TCB, Teixeira BR, et al. Molecular epidemiology of Blastocystis isolated from animals in the state of Rio de Janeiro, Brazil. PLoS One. 2019;14(1):e0210740.
5. 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(1):8821885. https://doi.org/10.1155/2021/8821885
6. Stenzel D, Boreham P. Blastocystis hominis revisited. Clinical Microbiol Rev. 1996;9(4):563-84.
7. Vinoth K, Deepa A, Vetriselvan S, Shalini V. Blastocystis sp., Parasite Associated with Gastrointestinal Disorders: An Overview of its Pathogenesis, Immune Modulation and Therapeutic Strategies. Curr Pharm Des. 2018;24(27):3172-5.
8. Javanmard E, Niyyati M, Ghasemi E, Mirjalali H, Aghdaei HA, Zali MR. Impacts of human development index and climate conditions on prevalence of Blastocystis: a systematic review and meta-analysis. Acta Trop. 2018;185:193-203.
9. Fusaro C, Bernal JE, Baldiris-Ávila R, et al. Molecular Prevalence and Subtypes Distribution of Blastocystis spp. in Humans of Latin America: A Systematic Review. Trop Med Infect Dis. 2024;9(2):38.
10. Liu L, Wang L, Tan F, Zhao W, Zeng F. Molecular investigation of Blastocystis sp. infections in wild rodents from the Inner Mongolian Autonomous Region and Liaoning province, China: High prevalence and dominance of ST4. Parasite. 2024;31. https://doi.org/10.1051/parasite/2024031
11. Jiménez PA, Jaimes JE, Ramírez JD. A summary of Blastocystis subtypes in North and South America. Parasit Vectors. 2019;12:1-9.
12. Ramírez JD, Sánchez A, Hernández C, et al. Geographic distribution of human Blastocystis subtypes in South America. Infect Genet Evol. 2016;41:32-5.
13. Salehi R, Rostami A, Mirjalali H, Stensvold C, Haghighi A. Genetic characterization of Blastocystis from poultry, livestock animals, and humans in the southwest region of Iran - zoonotic implications. Transbound Emerg Dis. 2021: 69(3):1178-1185.
14. Shams M, Shamsi L, Sadrebazzaz A, et al. A systematic review and meta-analysis on the global prevalence and subtypes distribution of Blastocystis sp. infection in cattle: A zoonotic concern. Comp Immunol Microbiol Infect Dis. 2021;76:101650.
15. Sharifi Y, Abbasi F, Shahabi S, Zaraei A, Mikaeili F, Sarkari B. Comparative genotyping of Blastocystis infecting cattle and human in the south of Iran. Comp Immunol Microbiol Infect Dis. 2020;72:101529.
16. Šloufová M, Lhotská Z, Jirků M, et al. Comparison of molecular diagnostic approaches for the detection and differentiation of the intestinal protist Blastocystis sp. in humans. Parasite. 2022;29:30.
17. El Safadi D, Cian A, Nourrisson C, et al. Prevalence, risk factors for infection and subtype distribution of the intestinal parasite Blastocystis sp. from a large-scale multi-center study in France. BMC Infect Dis. 2016;16(1):451.
18. Nithyamathi K, Chandramathi S, Kumar S. Predominance of Blastocystis sp. infection among school children in Peninsular Malaysia. PloS One. 2016;11(2):e0136709. https://doi.org/10.1371/journal.pone.0136709
19. Qadri S, al-Okaili GA, al-Dayel F. Clinical significance of Blastocystis hominis. J Clin Microbiol. 1989;27(11):2407-9.
20. Légeret C, Rüttimann C, Furlano RI, et al. Blastocystis in Swiss children: a practical approach. Eur J Pediatr. 2020;179(6):979-84.
21. Salem AI, El-Taweel HA, Madkour MA, Abd El-Latif NF, Abd-Elrazeq ES. Irritable bowel syndrome in Egyptian patients: plausible risk factors and association with intestinal protozoa. Trop Doct. 2019;49(3):184-8.
22. Kumarasamy V, Atroosh WM, Anbazhagan D, Abdalla MMI, Azzani M. 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.
23. Dogruman-Al F, Yoshikawa H, Kustimur S, Balaban N. PCR-based subtyping of Blastocystis isolates from symptomatic and asymptomatic individuals in a major hospital in Ankara, Turkey. Parasitol Res. 2009;106(1):263-8.
24. Niaraki SR, Hajialilo E, Delshad A, et al. Molecular epidemiology of Blastocystis spp. in children referred to Qods hospital in northwest of Iran. J Parasit Dis. 2020;44:151-8.
25. Cinek O, Polackova K, Odeh R, et al. Blastocystis in the faeces of children from six distant countries: prevalence, quantity, subtypes and the relation to the gut bacteriome. Parasit Vectors. 2021;14:1-16.
26. Wakid MH, Aldahhasi WT, Alsulami MN, El-Kady AM, Elshabrawy HA. Identification and genetic characterization of Blastocystis species in patients from Makkah, Saudi Arabia. Infect Drug Resist. 2022:491-501.
27. El-Wakil ES, Zalat RS, El-Badry AA. Mapping gut parasitism patterns in a cohort of Egyptians. Sci Rep. 2023;13(1):9961.
28. Khalili B, Khani MR, Taghipour S. Blastocystis hominis infection among hospitalized children due to diarrhea in Hajar hospital, Shahre-Kord, Iran. Arch Clin Infect Dis 2012.
2. Alexeieff A. Sur la nature des formations dites kystes de Trichomonas intestinalis. CR Soc Biol. 1911;71:296-8.
3. Villalobos G, López-Escamilla E, Olivo-Díaz A, et al. Genetic Variation among the Partial Gene Sequences of the Ribosomal Protein Large-Two, the Internal Transcribed Spacer, and the Small Ribosomal Subunit of Blastocystis sp. from Human Fecal Samples. Microorganisms. 2024; 12(6):1152.
4. Valença-Barbosa C, do Bomfim TCB, Teixeira BR, et al. Molecular epidemiology of Blastocystis isolated from animals in the state of Rio de Janeiro, Brazil. PLoS One. 2019;14(1):e0210740.
5. 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(1):8821885. https://doi.org/10.1155/2021/8821885
6. Stenzel D, Boreham P. Blastocystis hominis revisited. Clinical Microbiol Rev. 1996;9(4):563-84.
7. Vinoth K, Deepa A, Vetriselvan S, Shalini V. Blastocystis sp., Parasite Associated with Gastrointestinal Disorders: An Overview of its Pathogenesis, Immune Modulation and Therapeutic Strategies. Curr Pharm Des. 2018;24(27):3172-5.
8. Javanmard E, Niyyati M, Ghasemi E, Mirjalali H, Aghdaei HA, Zali MR. Impacts of human development index and climate conditions on prevalence of Blastocystis: a systematic review and meta-analysis. Acta Trop. 2018;185:193-203.
9. Fusaro C, Bernal JE, Baldiris-Ávila R, et al. Molecular Prevalence and Subtypes Distribution of Blastocystis spp. in Humans of Latin America: A Systematic Review. Trop Med Infect Dis. 2024;9(2):38.
10. Liu L, Wang L, Tan F, Zhao W, Zeng F. Molecular investigation of Blastocystis sp. infections in wild rodents from the Inner Mongolian Autonomous Region and Liaoning province, China: High prevalence and dominance of ST4. Parasite. 2024;31. https://doi.org/10.1051/parasite/2024031
11. Jiménez PA, Jaimes JE, Ramírez JD. A summary of Blastocystis subtypes in North and South America. Parasit Vectors. 2019;12:1-9.
12. Ramírez JD, Sánchez A, Hernández C, et al. Geographic distribution of human Blastocystis subtypes in South America. Infect Genet Evol. 2016;41:32-5.
13. Salehi R, Rostami A, Mirjalali H, Stensvold C, Haghighi A. Genetic characterization of Blastocystis from poultry, livestock animals, and humans in the southwest region of Iran - zoonotic implications. Transbound Emerg Dis. 2021: 69(3):1178-1185.
14. Shams M, Shamsi L, Sadrebazzaz A, et al. A systematic review and meta-analysis on the global prevalence and subtypes distribution of Blastocystis sp. infection in cattle: A zoonotic concern. Comp Immunol Microbiol Infect Dis. 2021;76:101650.
15. Sharifi Y, Abbasi F, Shahabi S, Zaraei A, Mikaeili F, Sarkari B. Comparative genotyping of Blastocystis infecting cattle and human in the south of Iran. Comp Immunol Microbiol Infect Dis. 2020;72:101529.
16. Šloufová M, Lhotská Z, Jirků M, et al. Comparison of molecular diagnostic approaches for the detection and differentiation of the intestinal protist Blastocystis sp. in humans. Parasite. 2022;29:30.
17. El Safadi D, Cian A, Nourrisson C, et al. Prevalence, risk factors for infection and subtype distribution of the intestinal parasite Blastocystis sp. from a large-scale multi-center study in France. BMC Infect Dis. 2016;16(1):451.
18. Nithyamathi K, Chandramathi S, Kumar S. Predominance of Blastocystis sp. infection among school children in Peninsular Malaysia. PloS One. 2016;11(2):e0136709. https://doi.org/10.1371/journal.pone.0136709
19. Qadri S, al-Okaili GA, al-Dayel F. Clinical significance of Blastocystis hominis. J Clin Microbiol. 1989;27(11):2407-9.
20. Légeret C, Rüttimann C, Furlano RI, et al. Blastocystis in Swiss children: a practical approach. Eur J Pediatr. 2020;179(6):979-84.
21. Salem AI, El-Taweel HA, Madkour MA, Abd El-Latif NF, Abd-Elrazeq ES. Irritable bowel syndrome in Egyptian patients: plausible risk factors and association with intestinal protozoa. Trop Doct. 2019;49(3):184-8.
22. Kumarasamy V, Atroosh WM, Anbazhagan D, Abdalla MMI, Azzani M. 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.
23. Dogruman-Al F, Yoshikawa H, Kustimur S, Balaban N. PCR-based subtyping of Blastocystis isolates from symptomatic and asymptomatic individuals in a major hospital in Ankara, Turkey. Parasitol Res. 2009;106(1):263-8.
24. Niaraki SR, Hajialilo E, Delshad A, et al. Molecular epidemiology of Blastocystis spp. in children referred to Qods hospital in northwest of Iran. J Parasit Dis. 2020;44:151-8.
25. Cinek O, Polackova K, Odeh R, et al. Blastocystis in the faeces of children from six distant countries: prevalence, quantity, subtypes and the relation to the gut bacteriome. Parasit Vectors. 2021;14:1-16.
26. Wakid MH, Aldahhasi WT, Alsulami MN, El-Kady AM, Elshabrawy HA. Identification and genetic characterization of Blastocystis species in patients from Makkah, Saudi Arabia. Infect Drug Resist. 2022:491-501.
27. El-Wakil ES, Zalat RS, El-Badry AA. Mapping gut parasitism patterns in a cohort of Egyptians. Sci Rep. 2023;13(1):9961.
28. Khalili B, Khani MR, Taghipour S. Blastocystis hominis infection among hospitalized children due to diarrhea in Hajar hospital, Shahre-Kord, Iran. Arch Clin Infect Dis 2012.
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| Issue | Vol 21 No 2 (2026) | |
| Section | Original Article(s) | |
| Keywords | ||
| Blastocystis spp. Genotype Children Iran | ||
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How to Cite
1.
Boulaghi S, Reihani A, Hosseini Farash BR, Sharifi Y, Ahmadi O, Samadi A, Salehi Sangani G, Najjari M, Berenji F, Zarean M. Molecular Detection and Subtype Characterization of Blastocystis spp. in Symptomatic Children Using PCR and Sequencing. Iran J Parasitol. 2026;21(2):258-264.
