Abiotrophia defectiva causing infectious crystalline keratopathy and corneal ulcer after penetrating keratoplasty: a case report

BACKGROUND Infectious crystalline keratopathy is commonly caused by Streptococcus viridans and other gram positive organisms. We present the first case of infectious crystalline keratopathy that developed into a corneal ulcer and grew Abiotrophia defectiva which responded well to topical and systemic antimicrobial therapy and did not require re-grafting. A 78-year-old man underwent penetrating keratoplasty for pseudophakic bullous keratopathy. He presented 1.5 years later with infectious crystalline keratopathy which progressed to a corneal ulcer. The patient received topical fortified vancomycin and moxifloxacin, as well as oral moxifloxacin. FINDINGS The corneal ulcer base was cultured and grew A. defectiva, or nutritionally deficient streptococcus. Complete resolution of the corneal infiltrates was obtained within three months. CONCLUSIONS Nutritionally deficient streptococcus has been implicated in numerous human diseases, including endocarditis, and is increasingly being recognized as an important pathogen. This represents the second reported case of A. defectiva causing infectious crystalline keratopathy in humans and the first case of A. defectiva successfully treated with antibiotics. This case shows that aggressive antibiotic therapy can be effective in A. defectiva-associated infectious crystalline keratopathy.