Molecular identification of Giardia lamblia; is there any correlation between diarrhea and genotyping in Iranian population?

Aim: The aim of this study is to investigate the molecular identification of Giardia lamblia in patients with diarrhea. Background: Giardiasis caused by Giardia lamblia is a common intestinal disease. Although this parasitic infection found in mammals including human, pets and livestock, but few species within the genus Giardia can infects humans. G. lamblia have seven complex genotypes termed (A-H). Genotype A and B the main causes of human infections. Patients and methods: Sixty seven microscopically positive G. Lamblia samples were collected from clinical laboratories in Isfahan province between June 2013 and February 2014. Extraction of genomic DNA was performed for 65 concentrated cysts and 2 cultured trophozoites. Partial sequences of tpi including 148-bp and 81-bp were amplified for detection the genotypes A and B using RFLP- PCR protocol respectively. Results: PCR results showed that out of 67 patients with giardiasis infection, genotype A (148 bp) was detected in 40 isolates (59.70%) compared to genotype B (81 bp) isolated was detected in 25 isolates (37.31%). Also two isolates (2.98%) had mix infection infected with genotype A and B. By comparing the frequency of genotype A (81.8%) and genotype B (13.6%), we found that genotype A is six times higher prevalence than genotype B in patients with diarrhea. Conclusion: We suggest that using sensitive techniques and larger sample for detection of G. lamblia genotypes and their subtypes would be necessary for investigation the immune system respond and correlation with diarrhea in the future studies in Iran.