Abstract
Pythium insidiosum is a parasitic oomycete that can cause keratitis and closely resembles fungus, both clinically and morphologically. It requires a trained microbiologist for its differentiation from fungal filaments and has poor response to antifungal therapy. We present a case of primary isolation of the organism from the vitreous cavity in a case of endophthalmitis. The infection spread quickly and involved all the ocular tissues. The eye had poor visual outcome despite a sequence of rapidly completed retinal and corneal surgeries along with initiation of anti-Pythium therapy.