A comprehensive molecular survey of Echinococcus granulosus in formalin-fixed paraffin-embedded tissues in human isolates in Turkey.

Cystic echinococcosis (CE) due to the formation of a hydatic cyst is a disease commonly seen in humans and animals that can be mortal sometimes. This disease, which is present in many countries around the world, constitutes a great problem for public health and the economy. The aim of this study was to identify Echinococcus granulosus genotypes in formalin-fixed, paraffin-embedded tissues. Tissue samples from 70 human patients with histologically confirmed echinococcosis were analysed by direct PCR of the 12S rRNA gene and by DNA sequence analysis of the CO1 gene of E. granulosus. Of the 70 samples, 29 (41.6%) could be genotypically characterized. Specifically, 26 of 70 were positive by direct G1-3 PCR of the 12S rRNA gene, two of which were identified as G1 by additional CO1 gene sequencing. All the 44 unidentified samples underwent CO1 sequencing, which yielded one G3 and two G6 records, while the remaining 41 samples gave no or inconclusive results. In conclusion, the results from the analysis of human isolates of E. granulosus confirmed the occurrence of G1, G3 and G6 genotypes in Turkey and indicated G1/G3 cluster (E. granulosus sensu stricto) as the predominant genotype.