Successful treatment of an extensively drug-resistant pseudomonal ulcer associated with contaminated artificial tears

PURPOSE: To report a case of bacterial keratitis caused by an extensively drug-resistant (XDR) Pseudomonas aeruginosa strain linked to contaminated artificial tears in the United States. The ulcer was successfully treated without perforation or extracorneal spread. OBSERVATIONS: An 81-year-old patient presented with a corneal ulcer of the right eye. The patient had a notable complex ocular history including glaucoma and corneal edema from corneal decompensation after prolonged retained lens fragment. Despite starting hourly fortified tobramycin and vancomycin eye drops, the infiltrate grew significantly by the next day. Bacterial culture grew Pseudomonas aeruginosa that was resistant to all tested antibiotics except for intermediate susceptibility to colistin and susceptibility to cefiderocol. Tobramycin-soaked collagen shields were applied daily for three days, and the patient was started on fortified colistin eye drops. The ulcer improved and, after seven weeks of therapy, the infiltrate resolved and resulted in a large central corneal scar. CONCLUSIONS AND IMPORTANCE: A combination of fortified colistin and tobramycin (administered via a combination of fortified eye drops and tobramycin-soaked collagen shields) appears to be an effective treatment option for extensively drug-resistant Pseudomonas aeruginosa corneal ulcers.