Polymicrobial Corneal Ulcer Following Plant Trauma And Oral Contamination: A Case Report

To report a rare case of polymicrobial corneal ulcer involving Streptococcus pyogenes, Acinetobacter species and Capnocytophaga sputigena, and to discuss diagnostic challenges and treatment strategies.

Department of Ophthalmology at Aier-Intech Eye Hospital in Beijing, China. The patient was initially evaluated at a local hospital before referral to our institution for advanced management of progressive corneal infection.

A 61-year-old male patient presented with left eye redness, pain, and decreased vision for 3 days following ocular trauma with Artemisia stalk. A companion attempted to remove visible foreign material from the eye using tongue.  Symptoms initially improved but then progressively worsened with increased pain and purulent discharge.

At the local hospital, he was diagnosed with left corneal ulcer and hypopyon. Treatment with levofloxacin eye drops and oral cefdinir was initiated with limited efficacy. Upon admission to our hospital, examination revealed hand motion vision, severe conjunctival congestion and edema, abundant purulent discharge, total corneal ulcer, and a 5 mm hypopyon. Despite intensive topical antibiotic therapy (levofloxacin, tobramycin, 5% vancomycin, and 4% amikacin), the corneal ulcer progressed rapidly with total corneal dissolution. On Day 3, therapeutic sclerokeratoplasty was performed. Histopathology revealed severe suppurative inflammation with PAS-positive filamentous structures.  Bacterial culture identified Streptococcus pyogenes and Acinetobacter species. Subsequent metagenomic sequencing of corneal tissue identified Capnocytophaga sputigena (70.52% abundance), confirming a triple-pathogen infection.  The infection was successfully controlled without recurrence. Five months postoperatively, the patient underwent DMEK combined with cataract surgery.  At 6-month follow-up, visual acuity improved to 0.2 with no signs of infection recurrence.

This case demonstrates the complexity of mixed bacterial corneal infections following plant-related trauma complicated by oral bacterial contamination.  The unique history of tongue contact with the ocular surface introduced Capnocytophaga sputigena, a typical oral commensal bacterium, into the wound, resulting in a polymicrobial infection. Metagenomic sequencing was crucial for identifying this fastidious pathogen, which was not detected by routine culture.  Early surgical intervention with penetrating keratoplasty combined with targeted antibiotic therapy based on comprehensive microbiological evaluation is essential for managing severe, rapidly progressive polymicrobial corneal infections.