Infectious keratitis after corneal crosslinking for keratoconus caused by levofloxacin-resistant microorganisms

INTRODUCTION: We present seven cases of infectious keratitis after corneal crosslinking (CXL) to attenuate keratoconus progression. METHODS: Of 524 consecutive patients who underwent CXL, 7 cases (4 males and 3 females; 21.5 ± 7.1 years) developed postoperative infectious keratitis were retrospectively reviewed. CXL was performed using the Dresden protocol or an accelerated protocol involving epithelial removal. RESULTS: All cases appeared normal on the day after surgery, but subsequently developed eye pain, blurred vision, corneal infiltration, inflammation of the anterior chamber, and ciliary injection on day 2 or 3. Methicillin-resistant Staphylococcus aureus was cultured from two eyes, methicillin-sensitive Staphylococcus aureus from two eyes, and Streptococcus pneumoniae from one eye. All detected bacteria were resistant to levofloxacin (LVFX). Five of the seven cases, especially four of the five severe cases with hypopyon, had a history of atopic dermatitis. All cases were observed after 2015. CONCLUSIONS: Infectious keratitis after CXL caused by microbes resistant to LVFX is increasing. In addition to careful postoperative observation of the cornea, preoperative evaluation of bacteria within the conjunctival sac evident on nasal swab cultures may be useful to identify potentially problematic microbes and inform the selection of appropriate antibiotics.