Intraocular protothecosis: a case report and literature review

Area of Science:

• Ophthalmology
• Infectious Diseases
• Medical Mycology

Background:

• Protothecosis is a rare human infection caused by Prototheca algae.
• Ocular involvement is exceptionally uncommon, with limited reported cases.
• This study details a unique case of ocular protothecosis.

Purpose of the Study:

• To report a rare case of ocular protothecosis in an immunocompetent patient.
• To describe the diagnostic process and treatment outcomes.
• To contribute to the limited literature on eye infections caused by Prototheca.

Main Methods:

• A case of an immunocompetent patient with visual loss post-cataract surgery was investigated.
• Ocular examination revealed retrolental deposits.
• Vitrectomy was performed; vitreous, snowbank, and fibrin samples were cultured and identified using MALDI-TOF.
• Antifungal susceptibility testing was conducted in vitro.
• Treatment involved vitrectomy, corticosteroids, posaconazole, and topical anti-inflammatories.

Main Results:

• Prototheca wickerhamii was identified as the causative agent.
• In vitro susceptibility testing showed low MICs for amphotericin B, posaconazole, isavuconazole, itraconazole, and voriconazole.
• The patient showed clinical improvement after combined treatment, though with residual visual acuity reduction.

Conclusions:

• Ocular protothecosis is rare, with diagnosis often relying on algal morphology and proteomic/molecular confirmation.
• Effective treatment typically combines surgical intervention, antifungal agents, and corticosteroids.
• This case underscores the importance of considering protothecosis in atypical ocular infections and the potential for good outcomes with multimodal therapy.