Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 12 4 2017 12 26 522 523 Mohammad RAYANI Dept. of Microbiology and Parasitology, School of Health, Bushehr University of Medical Sciences, Bushehr, Iran AND The Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran AND Dept. of Medical Microbiology and arasitology, Faculty of Medicine and Health Sciences, University Putra Malaysia, Serdang, Malaysia Gholamreza HATAM Basic Sciences in Infectious Diseases Research Center, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran Ngah Zasmy UNYAH Dept. of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, University Putra Malaysia, Serdang, Malaysia Abdolmajid ASHRAFMANSORI Basic Sciences in Infectious Diseases Research Center, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran Wan Omar ABDULLAH Dept. of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, University Putra Malaysia, Serdang, Malaysia Rukman Awang HAMAT Dept. of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, University Putra Malaysia, Serdang, Malaysia 2017 12 26 2017 12 26 Background: This study is the first phylogenetic genotype analysis of Giardia lamblia in Iran. The main objective was to determine genotyping and identify the sub-assemblages of Giardia lamblia isolates involved in the transmission of giardiasis in Fars Province, south of Iran, in 2012. Methods: Forty G. lamblia isolates were collected from the patient’s fecal samples with gastrointestinal discomfort referred to the health centers and hospitals in Shiraz, Fars Province, south of Iran. Purification of G. lamblia cysts from fecal samples and DNA extraction were performed using monolayer of sucrose density gradient and Phenol-Chloroform-Isoamylalcohol (PCI) respectively. Semi-nested PCR and sequence analysis were then performed using the primers (GDHeF, GDHiF, and GDHiR) which amplified a 432-bp fragment of Giardia glutamate dehydrogenase (gdh) gene. Phylogenetic analysis was carried out using a neighbor-joining tree composed of the nucleotide sequences of G. lamblia isolates obtained in this study and the known sequences isolates published in GenBank. Results: G. lamblia sub-assemblage AII was the most prevalent genotype with 80% of the cases and 20% of the cases belong to sub-assemblage BIII and BIV based on the DNA sequence of the gdh. G. lamblia isolates at Fars Province were widely distributed within assemblage A cluster (sub-assemblage AII) and the remaining isolates were dispersed throughout the assemblage B cluster (sub-assemblage BIII and BIV). Conclusion: PCR Sequencing and phylogenetic analysis was a proper molecular method for genotyping and discriminating of the of G. lamblia sub-assemblages in fecal samples, using the glutamate dehydrogenase gene that suggests a human contamination origin of giardiasis. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/1926 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/1926/787