Atopic keratoconjunctivitis complicated by Kocuria koreensis keratitis: the first case

BACKGROUND Patients with atopic dermatitis have a predisposition to Staphylococcus aureus and a Herpes simplex virus infection. The treatment of atopic diseases with steroid and immunosuppressive agents induces opportunistic infection. However, there is a concern regarding visual prognosis in patients with atopic keratoconjunctivitis (AKC) complicated with infectious keratitis. We report an unusual case of an atopic shield ulcer with Kocuria keratitis. CASE PRESENTATION A 51-year-old Japanese man presented with a 14-day history of eye pain and visual loss in his left eye. At the initial examination, a shield ulcer was observed in the upper-central cornea of the left eye, and the conjunctiva in both eyes had a velvety appearance due to papillary formation, as well as hyperemia and swelling in the palpebral area. The shield ulcer showed white stromal opacification in the marginal zone with a coral-like appearance. Samples were obtained by corneal scraping, and Kocuria sp. was identified by microbiological examination including culture and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The 16S rRNA gene sequence analysis was performed using isolated Kocuria strain from the patient. The obtained DNA sequence showed 99% homology with Kocuria koreensis. The combination of corneal scraping and instillation of cefmenoxime antibiotic ophthalmic solution was considered useful for the treatment of Kocuria keratitis. CONCLUSION Clinicians should be aware of Kocuria keratitis as a corneal complication of AKC, and that rapid diagnosis of Kocuria keratitis may improve visual prognosis.