Quadruple-Pathogen Spectrum In Rapidly Progressive Keratitis: Diagnostic And Surgical Challenges

To describe an aggressive keratitis exhibiting a quadruple microbiological spectrum, bacterial growth, Acanthamoeba-suggestive confocal findings, and culture-proven Pythium and filamentous fungi, culminating in graft reinfection and endophthalmitis. The case underscores the complexity of diagnosing and managing evolving polymicrobial infections.

Tertiary eye care center in North India

A 48-year-old female with rheumatoid arthritis presented with one month of pain, redness, and reduced vision in the right eye, worsening after topical steroid ointment was prescribed elsewhere for an eyelid lesion. Visual acuity was hand movements; the left eye was 6/6. Slit-lamp examination showed central corneal thinning with a 4 × 5 mm epithelial defect, minimal infiltrates, and stromal haze. AS-OCT confirmed severe thinning (248 µm). Infective keratitis was diagnosed, scrapings were obtained, and empirical fortified antibiotics were started.

Corneal perforation ensued, requiring therapeutic penetrating keratoplasty. Initial culture grew Staphylococcus aureus sensitive to Tobramycin. One week later, acute graft reinfection with deep stromal infiltrates developed. Fungal cultures were sterile, while confocal microscopy revealed hyperreflective cyst-like structures suggestive of Acanthamoeba. Owing to clinical deterioration despite inconclusive reports, repeat therapeutic keratoplasty was performed and broad-spectrum antibacterial and anti-amoebic therapy initiated.

Progressive limbal scleral involvement and ultrasonographic features of early endophthalmitis followed. Culture from the second host button demonstrated polymicrobial growth of Pythium, Alternaria, and Cladosporium. Despite intensive topical and intravitreal therapy, the infection progressed to fulminant endophthalmitis with no perception of light, and no further surgical intervention was planned.

This case highlights the diagnostic complexity of rapidly progressive keratitis with discordant microbiology and imaging findings in an immunologically vulnerable host. Discordance between clinical progression and initial microbiological results should prompt repeat sampling and reconsideration of atypical pathogens, including Pythium and mixed fungal infections. Host button analysis may reveal organisms not detected on surface scrapings. In rapidly progressive cases, early suspicion of deep or polymicrobial infection is critical, as delayed recognition can lead to graft failure and irreversible intraocular spread.