Molecular characterisation and genetic diversity of Acanthamoeba spp. among contact lens wearers in Northern Algeria: a first report

Acanthamoeba spp. are ubiquitous free-living amoebae and important opportunistic pathogens capable of causing Acanthamoeba keratitis (AK), a painful and potentially sight-threatening corneal infection most commonly associated with contact lens use. Despite the increasing global recognition of AK, epidemiological data from Algeria remain extremely limited, and the environmental and molecular epidemiology of Acanthamoeba in contact lens–related materials has not been previously documented. In this study, we investigated the occurrence, molecular characterisation, and genetic diversity of Acanthamoeba spp. isolated from contact lens-related materials collected from northern Algeria. A total of 39 specimens, including contact lens rinsing solutions and lens-case biofilm swabs obtained from contact lens users attending ophthalmology and optometry facilities in the Tizi-Ouzou region, were analysed using both morphological and molecular approaches. Following culture on non-nutrient agar seeded with Escherichia coli , free-living amoebae morphologically consistent with Acanthamoeba spp. were detected in 31/39 (79.4%) specimens. Molecular confirmation was achieved by conventional PCR amplification and bidirectional sequencing of the 18 S-rRNA gene. Maximum-Likelihood phylogenetic analysis of obtained sequences demonstrated that all isolates belonged to genotype T4, the genotype most frequently associated with human AK worldwide. Three isolates (ALG011, ALG019, ALG023) suggested the circulation of closely related local variants and inter-specific genetic divergence. In addition, no evidence of recombinant forms or genotype hybridization was observed among the Acanthamoeba specimens. These findings provide the first molecular evidence of Acanthamoeba contamination in contact lens–related materials in Algeria and highlight a potentially under-recognised public health risk among contact lens users. The high contamination rate observed in this study underscores the urgent need to strengthen laboratory diagnostic capacity, improve clinician awareness, promote appropriate contact lens hygiene practices, and implement environmental and clinical surveillance programmes to better assess the true burden of AK in Algeria.