Listeria monocytogenes sclerokeratitis: a case report and literature review

To report a case of Listeria monocytogenes sclerokeratitis and to review the literature.

Case report.

A 25-year-old non-contact lens-wearing male rugby player was referred with progressive infective sclerokeratitis unresponsive to topical antivirals and antibiotics. On examination, visual acuity was perception of light, and a large corneal abscess with overlying epithelial defect and hypopyon was present. The corneal lesion was cheesy white and raised with nasal scleritis. This raised the suspicion of a fungal keratitis. Empirical treatment with intensive topical antifungals was unsuccessful. A previous corneal scrape had been negative for bacteria and fungi. A corneal biopsy was performed, and Listeria monocytogenes was eventually isolated from enrichment culture. Antibiotic sensitivities showed it to be resistant to cefuroxime, methicillin, and ceftazidime but sensitive to all other antibiotics tested including ofloxacin. The treatment course was complicated by a corneal perforation that needed an emergency therapeutic penetrating keratoplasty. Five months later, best-corrected visual acuity was 6/9 + 4, with a clear functioning graft.

Listeria monocytogenes is a rare cause of corneal/scleral infection in humans. It often runs an aggressive course and responds poorly to initial intensive antibiotic treatment despite favorable in vitro sensitivities. It can be difficult to culture, and we suggest a corneal biopsy with extended incubation to improve diagnostic yield.