Genotyping and molecular analysis of Enterocytozoon bieneusi isolated from immunocompromised patients in Iran

- We identified E. bieneusi from different immunocompromised patients using SSU rDNA and characterize all isolates using ITS fragment.
- We performed molecular analysis upon ITS fragment of our isolates and the isolates that were retrieved from GenBank.
- ITS fragment in E. bieneusi has highly variable region among different genotypes and even in the same genotypes.
- Specific genotypes more likely do not have relationship with type of immunodeficiency.
- Importance of zoonotic transmission should be a concern.

Microsporidia are known as opportunistic unicellular pathogens, particularly so in individuals with congenital or acquired immunodeficiency. Enterocytozoon bieneusi is one of the most common species infecting both immunocompromised and immunocompetent individuals. The aim of this study was to assess the distribution of E. bieneusi genotypes among immunocompromised patients in Iran. From 329 stool samples referred for parasitological analysis during 2011-2014, 14 samples from immunocompromised patients proving positive for E. bieneusi by SSU rDNA analysis were selected. Genotyping was carried out using specific primers targeting the Internal Transcribed Spacer (ITS) region. Subsequently, all samples were sequenced and results queried against the GenBank database. Moreover, sequences were subject to phylogenetic analysis. The expected amplification product was generated for all samples. Genotype D was identified in patients with HIV +/AIDS, transplant recipients, and cancer patients, while Genotype E was identified only in cancer and HIV +/AIDS patients. Phylogenetic analysis revealed that there was no relationship between genotypes and types of immunosuppression, whereas most genotype D isolates grouped with those described previously from cattle, horses, birds, and humans. E. bieneusi genotype D appears to be the most frequent genotype in immunocompromised patients, while Genotype E was observed only in HIV +/AIDS patients and cancer patients, not transplant recipients.