Objective To identify the frequencies (F) of ferredoxin and nitroreductase mutations on Iranian clinical isolates of Giardia lamblia in order to predict whether the nitazoxanide can be prescribed as suitable drug for symptomatic to metronidazole-resistant giardiasis. Methods Forty Giardia lamblia isolates as of 38 symptomatic and two metronidazole-resistant patients were collected from Iran. DNAs were extracted and amplified by targeting ferredoxin and GlNR genes. The amplicons were directly sequenced to determine gene mutations. Results The various amino acid substitutions (F: 20%, Haplotype diversity: 0.891, Tajima's D: −0.440 13) were identified by analyzing ferredoxin gene in four symptomatic and two resistant isolates. Only two haplotypes (F: 5%, HD: 0.345; Tajima's D: 0.778 15) characterized in metronidazole-resistant isolates of GlNR, however, no point mutations was found in symptomatic isolates. Conclusions Non-synonymous mutations of ferredoxin oxidoreductase gene reduce translational regulatory protein's binding affinity which concludes reduction of ferredoxin expression and its activity. This leads to decrease in metronidazole drug delivery into the cells. Mutations in these isolates may lead to their resistance to metronidazole. No to low synonymous mutations of GlNR demonstrates that nitazoxanide can be prescribed as promising alternative treatment for symptomatic to metronidazole-resistant giardiasis in Iranian clinical isolates.

Objective To examine all evidence about Microsporidia infection in vertebrate/invertebrate hosts and Iranian populations distributed in different regions of the country. Methods All published articles up to December 2015, including descriptive and cross-sectional studies related to the prevalence and genotyping of Microsporidia infection in Iran, was considered in this systematic review. The meta-analysis was done using the random-effects model and Stats Direct statistical software. MEGA 5.05 software and maximum likelihood algorithm with Kimura 2-parameter model were used for phylogenetic analysis. Results Of the 1152 investigated studies, 33 eligible studies reported a prevalence of Microsporidia infection in vertebrate and invertebrate hosts. According to this systematic review, the overall prevalence rate of Microsporidia infection in immunocompromised patients in Iran was 8.18%. Furthermore, the overall prevalence rate of Microsporidia infection in immunocompromised patients with chronic diarrhoea, patients with non-diarrhoea, gastroenteritis, and patients with CD4 (<200 cells/μL) was 15.4%, 4.1%, 0.5%, and 12.9% respectively. The highest prevalence rate of human and animal Microsporidia was estimated in Kerman (29%) and Khuzestan (26.5%). The overall prevalence rate of Microsporidia infection in honeybees using the random-effects model was 40%. Furthermore, the highest prevalence rate of nosemosis was described in East Azerbaijan (48.2%). The most Microsporidia isolates from immunocompromised patients and pigeons in Iran belonged to genotypes D (n = 16; 50%) and E (n = 6; 20.6%) of Enterocytozoon bieneusi. Conclusions This study may be the first systematic review and meta-analysis that provides a broad outlook on the prevalence of microsporidiosis in Iran. It is necessary to investigate Microsporidia infection in vertebrate and invertebrate hosts and environmental resources in Iran.