Isolation and identification of free-living amoeba from contact lenses: Thermal and osmotic tolerance in relation to their pathogenicity.

doi:10.21608/aunj.2022.219654

Isolation and identification of free-living amoeba from contact lenses: Thermal and osmotic tolerance in relation to their pathogenicity.

10.21608/aunj.2022.219654

Abstract

Free-living amoeba (FLA) such as Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris, and Sappinia diploidea are widely distributed natural and human-made environments which may cause human diseases. For example, N. fowleri causes fatal encephalitis, Acanthamoeba and Balamuthia cause chronic granulomatous encephalitis and Acanthamoeba also can cause cutaneous lesions and Amoebic Keratitis (AK) that is associated with the use of contact lens. In the present work, FLA were isolated from new and used lenses and lenses preservative solutions and identified by morphological characteristics then their tolerance to high temperature and osmosis were studied. The results showed that Acanthamoeba spp. is the main amoeba isolated from lenses and lens solution, and A. polyphaga had higher pathogenicity than the rest of the genera due to its ability to grow at all temperatures and osmosis tested. While both N. fowleri did not grow at any of the tested osmotic levels but grew at the tested temperatures so they were considered as non-pathogenic.

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