Genotyping of Acanthamoeba Species Isolated from Keratitis Patients by PCR Sequencing Methods in Tehran, Iran

Amoebae of the genus Acanthamoeba are unicellular amphizoic opportunistic pathogens that may cause fatal granulomatous encephalitis, eye keratitis, amebic pneumonitis and skin nodules as well as abscesses in humans and animals. Acanthamoeba keratitis is caused by trauma to the eye, contaminated cleaning solutions and the use of contact lenses. The aim of the present study was to identify the genotypes of Acanthamoeba in all patients with a clinical diagnosis of Acanthamoeba keratitis referring to eye clinic in Tehran using polymerase chain reaction (PCR).

In this study, samples were collected from 35 patients who had referred to the eye clinic and were cultured on 1.5% non-nutrient agar. DNA was extracted, and then PCR amplification was performed using genus specific primers. Sequencing analysis and basic local alignment search tool search were conducted to determine the genotypes. Phylogenetic tree was generated using maximum likely algorithm in phylogenetic program MEGA version 6.

Eight cases were positive for Acanthamoeba using genus specific primer pairs. All specimens were reported as genotype T4.

Determination of genotypes showed all isolates belonging to genotype T4; this abundance may be due to its higher prevalence in the environment or its greater virulence. However, further analysis of clinical and environmental samples is necessary to clarify this property.