Moraxella nonliquefaciens superinfecting herpes simplex keratitis

Moraxella nonliquefaciens (M. nonliquefaciens) is a low pathogenicity microorganism, which rarely causes ocular infections, unless there is a predisposing factor. The main clinical manifestation of M. nonliquefaciens ocular infections is endophthalmitis and only five cases of corneal infection have been reported. This work shows an update in M. nonliquefaciens corneal infections, and the first reported case of keratitis due to M. nonliquefaciens superinfecting herpes simplex infection.

A 84-year old woman with worsening of her herpes simplex keratitis, diagnosed, and treated 2 days before. The slit lamp showed deep paracentral infiltrate and hypopyon. A corneal sample was collected for culture prior to initiation of empiric antibiotic therapy with vancomycin and ceftazidime fortified, oral acyclovir, and cyclopentolate. The strain was identified as M. nonliquefaciens and topical antibiotic therapy was adjusted to ciprofloxacin and ceftazidime. After 2 weeks, the epithelial defect and the infiltrate were resolved and prednisolone was added to the regimen. As the corneal oedema and neovascularization decreased, acyclovir, and prednisolone were slowly tapered. About 4 months later, the visual outcome was 20/50 and the ophthalmic examination showed a clear cornea with a paracentral leucoma.

Keratitis due to M. nonliquefaciens is rare and should be suspected in patients with local predisposing factors such as corneal damage or previous corneal infection. Prompt and appropriate combined treatment for the predisposing lesions and the keratitis may improve the prognosis and avoid a more aggressive approach.