Double-Biguanide Therapy for Resistant Acanthamoeba Keratitis

AIMS: To report the clinical and diagnostic findings of a patient with Acanthamoeba keratitis resistant to both polyhexamethylene biguanide (PHMB)-hexamidine and chlorhexidine-hexamidine treatment. METHODS: Slit-lamp biomicroscopy, corneal cell scraping and histopathology were performed on a 39-year-old woman presenting with corneal ulcer in her left eye. RESULTS: The patient was successfully treated with PHMB-chlorhexidine association therapy. Subsequent perforating keratoplasty remained clear at the last follow-up visit after 7 months and increased visual acuity to 20/20 with correction. CONCLUSIONS: This case emphasizes the proteiform aspects of Acanthamoeba drug resistance, and suggests that PHMB-chlorhexidine association might represent an additional option for cases resistant to standard therapy.