Evidence map›Paper›PMID 41928127›Full record

ArticleBMC infectious diseases2026

Association of Blastocystis species subtypes 3 and 4 with intestinal inflammation and response to metronidazole in symptomatic patients.

Noha M Amin, Amira R Ismail, Shimaa M Abdel Aal, Aly ELkazaz, Hala Ramadan, Ahmed Mohamed Shenawy, Shaimaa Mohamed Ali, Shimaa Saad El-Din, Magda Sa Abdeltawab

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Article in BMC infectious diseases, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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4 · The record

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5 · Who and what money

Authors and funding

9 authors.

Noha M AminDepartment of Medical Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.
Amira R IsmailDepartment of Medical Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.
Shimaa M Abdel AalDepartment of Medical Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.
Aly ELkazazDepartment of Pediatrics, Faculty of Medicine, Cairo University, Cairo, Egypt.
Hala RamadanDepartment of Internal medicine, Faculty of Medicine, Cairo University, Cairo, Egypt.
Ahmed Mohamed ShenawyDepartment of Internal medicine, Faculty of Medicine, Cairo University, Cairo, Egypt.
Shaimaa Mohamed AliDepartment of Internal medicine, Faculty of Medicine, Cairo University, Cairo, Egypt.
Shimaa Saad El-DinDepartment of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, Cairo, Egypt. dr.shimaa.saad@cu.edu.eg.
Magda Sa AbdeltawabDepartment of Medical Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundBlastocystis spp. (BC) often passes as a harmless resident of the gut. However, it may be associated with gastrointestinal disturbances, such as abdominal pain and diarrhea. The variation in the clinical spectrum of BC infection is, in part, due to its diverse genotypic profile, where ongoing research continues to discover new BC subtypes. This study aimed at investigating the association between different BC subtypes and intestinal inflammation as assessed by fecal calprotectin (FCP) and tumor necrosis factor alpha (TNF-α) levels.

methodsPatients complaining of gastrointestinal tract (GIT) symptoms were investigated for the presence of BC infection by microscopy and stool culture on Jones’ medium. Out of 163 patients, 88 were confirmed to be infected with BC. They were further divided according to the dominant BC subtype by RFLP genotyping. Patients were treated with metronidazole at a dose of 250 mg 3 times daily for ten days and were evaluated for symptom improvement after the treatment course. Moreover, FCP and TNF-α levels were measured in stool samples by ELISA before and after therapy.

resultsBC subtype 3 was found to be the dominant subtype in 62 samples (70.5%), while subtype 4 was dominant in 26 samples (29.5%). A higher number of patients infected with BC subtype 3 reported the presence of GIT manifestations. After treatment, 17 subtype 3-infected patients (27.4%) witnessed improvement of their GIT symptoms, as compared to 9 patients infected with BC subtype 4 (34.6%). In subtype 3 infected patients, 71% were free of BC stages by both microscopic examination and stool culture, while 92.3% of patients infected with subtype 4 showed fecal parasite clearance. FCP and TNF-α levels were higher in patients infected with BC subtype 3 as compared to BC subtype 4, both before and after treatment with metronidazole. In the BC subtype 3-infected groups, fecal TNF-α and FCP levels decreased significantly after treatment.

conclusionIn our cohort study, BC subtype 3 was the most prevalent subtype among patients reporting gastrointestinal symptoms. The ST3 group exhibited numerically higher inflammatory markers compared to ST4. These trends shed light on the potential link between Blastocystis genetic diversity and intestinal inflammation. Although the observational nature of this study and the unequal group sizes limit the ability to establish a definitive causal relationship, these findings provide a BC subtype-oriented diagnostic and therapeutic design within a hospital-based setting that could facilitate the design of more tailored management strategies for patients with BC-associated symptoms.

Indexed as

Antiprotozoal AgentsBlastocystisBlastocystis InfectionsMetronidazoleAdultAgedFecesFemaleGenotypeHumansInflammationLeukocyte L1 Antigen ComplexMaleMiddle AgedTumor Necrosis Factor-alphaAntiprotozoal AgentsLeukocyte L1 Antigen ComplexMetronidazoleTumor Necrosis Factor-alphaBC subtypesBlastocystis spp.Fecal calprotectinRFLPTNF-α

Identifiers

PMID41928127
PMCPMC13064339

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.