Stenotrophomonas maltophilia - A Case Series of a Rare Keratitis Affecting Patients With Bandage Contact Lens

OBJECTIVES:Stenotrophomonas maltophilia is an opportunistic pathogen known to form biofilms on contact lens and case surfaces that may result in permanent visual loss in cases of microbial keratitis. Because of its multiple drug resistance and extremely low incidence, there is little consensus on treatment. We investigated the predisposing factors, management, and visual outcomes in a small case series of patients to better inform the management of this rarely reported keratitis. METHODS:Retrospective analysis of medical records was performed at a single tertiary referral center between 2011 and 2017. The case notes of each microbiology confirmed S. maltophilia keratitis were examined. RESULTS:Six cases were identified (four men) with a median age of 62 years (range 1 month-90 years) and pre-existing ocular surface disease in all cases. At presentation, four patients were using bandage contact lenses and three were on topical antibiotic and steroid medications. Initial antibiotic treatment was intensive topical 0.3% ofloxacin and 5% cefuroxime, which was modified based on corneal scrape culture and sensitivity and clinical findings. One patient chose not to complete the treatment course. The 5 remaining patients had complete resolution of ulceration over a mean of 2.9 months (SD 0.8 months). CONCLUSIONS:Contact lens in the context of ocular surface problems, prolonged topical antibiotic and steroid treatments may predispose to S. maltophilia, a rare cause of keratitis. We report successful treatment with case-specific combinations of topical antibiotics such as fluoroquinolone, cotrimoxazole, and/or cephalosporin agents, although visual outcomes remain poor due to corneal scar.