Isolation and Genotyping of Acanthamoeba Strains from Corneal Scraps

Purpose: To determine the prevalence and genotype of Acanthamoeba keratitis (AK) in patients referred to Farabi referral eye center Methods: In this study, corneal scraping specimens that obtained from keratitis patients examined for Acanthamoeba and its genotype identifications. Direct smears, cultivation in non-nutrient agar (NNA) followed by PCR were chosen as the basic diagnostic methods. The positive patients checked by confocal microscopy. For genotypic identifications of isolates from keratitis patients, DF3 region of rRNA gene amplified in PCR. Results: Five clinical specimens (5.6%) out of 89 collected samples showed positive by culture and PCR analysis. Then the results compared with confocal microscopy and all five patients confirmed as AK. The statistical analysis showed significant relation between infection with Acanthamoeba and wearing contact lenses (p=0.001). A logistic regression analysis showed, there is an inverse weak statistical relation between age and infection (p=0.07). Sequence analysis demonstrated that T4 is the predominant genotype in these isolates and the primary genotype in AK. All cases were unilateral and pain, redness, tearing, and light sensitivity were the most common clinical symptoms among them. Conclusion: Genotypic identification of the microorganism helps epidemiologists and parasitologists to study the transmission routes of infection in different areas. The results of this study also showed that NNA as diagnostic and economical method could be used in areas with low ophthalmic equipment such as confocal microscopy, but it is time consuming.