Investigation of Giardia intestinalis genotypes in giardiasis patients diagnosed in Celal Bayar University Medical School's Hospital (Manisa) with Real-Time PCR

Real time PCR has been used commonly in the diagnosis of many parasitogical diseases. Giardia is a genus of intestinal flagellate protozoa, including six species that infect several vertebrates. Giardia intestinalis is currently the only known species found in humans, while it is also found in other mammals such as pets and livestock. The morphological differences among the isolates of G. intestinalis are quite little; however, latest molecular biological studies have demonstrated seven distinct assemblages (A-G) belonging to G. intestinalis, which is not possible to discriminate with routine microscopic methods.The purpose of the study was to assess the genotypes of clinical isolates of Giardia intestinalis using Real Time PCR, and evaluate their epidemiological and clinical characteristics in Manisa, Turkey. Fourty-five isolates from G.intestinalis-infected patients diagnosed during the routine microscopic examination with wet mount, formalin ethyl acetate concentration and trichrome staining in the laboratory of Celal Bayar University School of Medicine Department of Parasitology, were included in the study. The isolates were amplified successfully with real time nested PCR by targeting triose phosphate isomerase and using sequence-specific DNA probs for identified genotypes by melting-point analysis. Thirty-three of 45 samples (73.3%) were found to be genotype A, 5 samples (11.1%) were found to be genotype B, while the remaining 7 (15.5%) samples were found to be mixed infection (A+B). Real time PCR was found tobe 100% sensitive and specific.In the present study, a Real Time PCR test procedure with 100% of sensitivity and specificity was identified to be used in the clinical diagnosis of giardiasis patients. In addition, the results showed that Assemblage A was more common in our patient series, as idenitified in the previous study conducted in Manisa. After confirmation of the method through assessments with more clinical samples, we will surely obtain more precise data concerning the epidemiology of giardiosis our region.Key words: Giardia intestinalis, genotype, real time PCR, Turkey