Genetic Variation of Isolates from Food-handlers in Kashan, Central Iran.

Background: Based on genotyping study of human isolates of ; humans are mainly infected by two assemblages A and B. The present study was carried out to determine the sub-assemblages of isolated from food handlers referred to Kashan health centers, central Iran, 2015.

Methods: In this cross-sectional study, 3653 stool samples collected from food-handlers that annually refer to health center for getting a health certification and examined microscopically for cyst. Totally, 44 isolates were selected from 47 positive samples. Cysts were partially purified by the sucrose density gradient method. After freeze-thaw cycles, genomic DNA was extracted using QIAamp Stool Mini kit. A single step PCR-RFLP method was used to amplify a 458bp fragment at the glutamate dehydrogenase ) locus, restriction enzymes and were used for distinguish between genotypes A and B and their subgroups.

Results: Of 44 isolates, 24(54.5%) were sub-assemblage AII, 9(20.5%) group B including 7(15.9%) BIII and 2(4.6%) BIV sub-assemblage and 11(25%) isolates showed a mixed pattern of AII and B. Sub-assemblage AI was not detected in this study.

Conclusion: The higher rate of sub-assemblage AII demonstrated an anthroponotic origin of the infection so infected food-handlers could directly transmit this protozoan to consumers via contaminated food and water. For finding of pattern of transmission and distribution of assemblages and sub-assemblage, more studies in human and animal population in different regions are necessary.