Multidrug-Resistant Acanthamoeba Keratitis Caused by the T4 Genotype: A Case Report Publisher Pubmed



Atighehchian M ; Latifi A ; Kazemirad E ; Kasiri M ; Zareighanavati M
Source: Parasitology Research Published:2026

Abstract

This report describes the case of a 28-year-old woman, who presented with a two-week history of severe ocular pain and photophobia in her right eye. She was a soft contact lens wearer with no history of ocular trauma or systemic illness. Ophthalmic examination revealed conjunctival hyperemia, epithelial irregularities, and a developing ring-shaped stromal infiltrate. In vivo confocal microscopy demonstrated double-walled hyperreflective cysts, and culture followed by PCR and sequencing confirmed the presence of Acanthamoeba T4 genotype. Despite intensive treatment with topical polyhexamethylene biguanide, chlorhexidine, propamidine, and voriconazole, as well as oral miltefosine, the infection progressed, leading to stromal necrosis. The patient underwent two therapeutic penetrating keratoplasties; however, the disease continued to advance, eventually resulting in phthisis bulbi and permanent vision loss. This case highlights the potential for aggressive, clinically refractory Acanthamoeba keratitis caused by the T4 genotype, emphasizing the importance of early diagnosis, vigilant monitoring, and timely surgical intervention in resistant cases. © The Author(s) 2026.