To report a case of corneal ulcer due to Alcaligenes xylosoxidans in a soft contact lens wearer.

A 20-year-old female patient presented with a corneal ulcer. The patient had been wearing soft contact lenses over 6 months. The ulcer had a typical appearance, similar to that of immune infiltration due to contact lenses. However, the corneal scraping and culture yielded Alcaligenes xylosoxidans, which is susceptible to ceftazidime and levofloxacine in the antibiotic susceptibility test. After treatment with topical antibiotics, her eye improved, with only a mild corneal scar remaining.

Alcaligenes xylosoxidans should be considered as a potential causal pathogen of keratitis upon wearing soft contact lenses. Additionally, any lesion should be suspected as a bacterial corneal ulcer, even if appearing as an immune infiltration due to contact lenses.