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.