Unveiling the hidden threat: prevalence of Enterocytozoon bieneusi and other intestinal parasitic infections among organ transplant recipients in Southern Iran.

Background: Individuals with compromised immune systems, such as organ transplant recipients who are on immunosuppressive therapy to prevent graft rejection, are at an increased risk of acquiring, disseminating, or experiencing recurrence parasitic infections.

Methods: This study aimed to identify the types and prevalence of parasitic diseases among transplant patients at a comprehensive transplant center in Fars Province, southern Iran. The subjects of the study were 150 organ transplant recipients (kidney, liver, intestine, simultaneous pancreas and kidney [SPK]) who were at least two months post-transplantation. Stool samples were collected from each participant, and demographics along with clinical features were recorded. The stool samples underwent parasitological examination, including direct examination, zinc sulfate flotation, formalin-ethyl acetate sedimentation, trichrome, and acid-fast staining to detect protozoan and helminthic infections. Samples positive for Blastocystis sp., as well as all diarrheal samples suspected of having microsporidia or intestinal coccidia, were further investigated using molecular methods. Sequencing was performed on the PCR products obtained from 10 Blastocystis samples. The resulting sequences were submitted to the Blastocystis 18 S database for GenBank sequence queries.

Results: The mean age of the participants was 46.24 (± 15.13), ranging from 18 to 85 years. Among the 150 subjects, 96 (64%) were male and 54 (36%) were female. The majority had undergone kidney transplantation (52.66%), followed by liver transplantation (46%). The participants resided in various provinces of Iran, with the majority (61.33%) living in Fars province. Overall, 63 (42%) individuals were found to be infected with at least one type of intestinal parasite. Blastocystis sp., the most commonly detected parasite, was detected in 58 (38.66%) cases, Entamoeba coli and Iodamoeba butchlii were each detected in 2 (1.33%) cases, while Enterocytozoon bieneusi was identified in 1 (0.66%) case. No helminth infections were detected in any of the subjects. Sequencing of Blastocystis sp. revealed subtype 3 (ST3).

Conclusion: The study highlights a high prevalence of intestinal protozoa, particularly Blastocystis sp., among transplant recipients in southern Iran. The detection of E. bieneusi underscores the critical need for greater awareness of these parasitic agents, especially in cases presenting with diarrhea.