Pharmacotherapy of Pythium insidiosum keratitis - a contemporary update

Pythium insidiosum keratitis is an emerging, vision-threatening corneal infection that is increasingly recognized worldwide, particularly in tropical and agrarian regions. Owing to its close clinical resemblance to fungal keratitis, delayed diagnosis and inappropriate antifungal therapy frequently result in rapid stromal destruction, therapeutic keratoplasty, and poor visual outcomes. Unlike true fungi, Pythium insidiosum is an oomycete lacking ergosterol in its cell membrane, rendering conventional antifungal agents largely ineffective and necessitating a paradigm shift toward targeted pharmacotherapy.

This review summarizes contemporary advances in the pharmacologic management of Pythium insidiosum keratitis, including mechanisms underlying antifungal resistance, current evidence supporting antibacterial-based therapy such as linezolid and azithromycin, adjunctive anti-collagenolytic and anti-inflammatory approaches, and emerging anti-oomycete therapeutics. Literature from PubMed, Scopus, Embase, and Web of Science was reviewed to evaluate drug susceptibility patterns, translational therapeutic strategies, and evolving precision medicine approaches.

Management of Pythium keratitis is transitioning from empirical antifungal therapy toward targeted anti-oomycete (antibacterial) treatment guided by rapid diagnostics and susceptibility profiling. Future advances will likely integrate molecular diagnostics, AI-assisted therapeutic prediction, nanotechnology-enabled drug delivery, and personalized pharmacologic and surgical strategies to improve globe salvage and visual outcomes.