Molecular epidemiology of Enterocytozoon bieneusi and Encephalitozoon sp., among immunocompromised and immunocompetent subjects in Iran.

Intestinal microsporidiosis is known as an opportunistic infection in immunocompromised patients. The current study aimed to investigate intestinal microsporidia infection in human subjects with/without immunodeficiency. Totally, 600 stool samples were collected from immunocompromised (254) and immunocompetent (346) subjects. DNA extraction was performed and the SSU rRNA and the ITS genes were amplified to detect and characterize microsporidia and the relevant genotypes. Phylogenetic trees were drawn using MEGA7 software to illustrate the correlation between isolates. From 600 enrolled subjects, 283 and 317 were male and female, respectively. The average age ± SD of all tested subjects was 28.85 ± 26.92. The results of PCR demonstrated the presence of E. bieneusi and Encephalitozoon sp., among 10/600 (1.67%) and 26/600 (4.33%) of samples, respectively. Accordingly, E. bieneusi was seen among 4/346 (1.15%), 1/53 (1.88%), 3/124 (2.42%), and 2/63 (3.17%), and Encephalitozoon sp., was detected from 17/346 (4.91%), 3/53 (5.36%), 4/124 (3.22%) and 2/63 (3.17%) of healthy subjects, RA patients, cancer patients, and transplantation recipients, respectively. Statistical significant correlation was not seen between the presence of microsporidia and age, gender, stool appearance, and geographical region. Molecular analysis showed that all E. bieneusi were the genotype D. Phylogenetic tree demonstrated no classification according to the presence/absence of immunodeficiency, geographical locations and presence of diarrhea. The high prevalence of Encephalitozoon sp., in comparison to E. bieneusi in this study suggested the importance of this genus alongside with E. bieneusi in Iran. In addition, predominance of the genotype D highlighted the wide distribution of this genotype in Iran.