Biofilm formation in infectious crystalline keratopathy due to Candida albicans

Infectious crystalline keratopathy (ICK) is an uncommon, indolent corneal infection in which the slow clinical course contrasts with the rapid laboratory growth and microbiological sensitivities of the infecting organism. This prospective study aimed to determine whether biofilm production was the cause of this disparity. A case of failed medical management of ICK in a patient with Stevens-Johnson syndrome is presented. A penetrating keratoplasty yielded corneal tissue that was freshly fixed for electron microscopy using 0.05% ruthenium red and 2.5% gluteraldehyde. Candida albicans was grown from 3/3 broths, and fungi with morphology consistent with Candida were seen on histological examination. Electron microscopy revealed microorganisms morphologically typical of Candida surrounded by a polysaccharide-rich glycocalyx consistent with a biofilm. We concluded that Candida albicans is capable of producing a biofilm and is a known cause of ICK. This case is supportive evidence that biofilm production is associated with cases of ICK and may explain the chronic, pauciinflammatory features of ICK and its relative resistance to antibiotic treatment.