Molecular characterisation of echinococcus granulosus isolates from Aydin/Turkey BY sequenci̇ng of mitochondrial cytochrome c oxidase I

Echinococcus granulosus (E. granulosus), the aetiological agent of Cystic Echinococcosis (CE) in humans and livestock, is a widely distributed zoonotic pathogen tapeworm that causes significant morbidity and economic loses in many countries, and also in Turkey. A high level of genetic diversity was reported between the isolates of E. granulosus. Up to now, ten genotypes (G1-10) of E. granulosus have been identified from different hosts by molecular genetic analysis. In most of the studies from Turkey and all around the world, G1 (sheep strain) was reported as the prevalent genotype in human and other hosts. Additionally, G3, G6 and G7 were also reported from Turkey. However, we still have limited information about the genotypes of human E. granulosus in Turkey. The aim of the present study was to determine genotypes of E. granulosus isolates in Aydın, Turkey. The study was conducted in Adnan Menderes University, Parasitology Laboratory. Genomic DNA was isolated with a commercially available kit (QIAamp DNA Mini Kit, Germany) from cyst fluids, aspirated during surgery. Mitochondrial, cytochrome oxidase subunit I (cox1) gene, was amplified with a single round PCR and sequenced. The sequences were analysed by using BLAST tool on website of NCBI. Genotypes were determined according to closest or exact matches in comparison with previously deposited reference sequences in Genbank. Additionally, a phylogenetic tree was constructed by using Neighbour Joining Tree. A total of 20 isolates were successfully amplified and sequences were acquired. DNA was isolated from of cyst fluids and 22 isolates were amplified with PCR. However, two of sequences showed little similarity with E. granulosus cox1 gene and they were eliminated. Four different sequences were identified by the alignment of isolate sequences in the present study. Sheep strain G1 was accounted the greatest majority of our isolates (15 isolates, 75%). The other genotype was G 6/7 (5 isolates 25%) which might be pig or camel originated genotypes. Similarly, for the 15 isolates which were identified as G1 there was one base substitution in one of them (C234T). Our study confirms the previous findings in Turkey that have indicated the predominance of sheep strain (G1). Additionally, similar to our findings pig or camel (G6/7) strain was reported less than sheep strain in previous studies from Turkey. It may be concluded that sheep and wild boars and camels in the study area may be the main agent of human CE cases in study area. The research has also shown that cox1 gene is a valuable target for determination of E. granulosus genotypes. It may be concluded that further studies in the field of CE concerning the genotypes of E. granulosus from different regions of Turkey will be important and will contribute the control of CE. Keywords: Echinococcus granulosus, cystic echinococcosis, genotyping, cox1, Aydin