Nontuberculous mycobacterial keratitis: report of two cases causing infectious crystalline keratopathy

We report two cases of nontuberculous mycobacterial keratitis, occurring after corneal trauma with superficial foreign body and after perforating keratoplasty for alkali burn, respectively. Patients initially presented with indolent white corneal infiltrates, which did not respond to topical treatment. Both secondarily developed infectious crystalline keratopathy with unequal intensity. In the first case, the excised flap of lamellar keratectomy was cultured, allowing identification of Mycobacterium abscessus. Mycobacterium chelonae was isolated from a corneal biopsy in the second case. The clinical course showed poor response to antibiotic therapy consisting of ciprofloxacin and amikacin drops in conjunction with a new-generation oral macrolide. Corneal infection recurred after lamellar keratectomy in the first patient. Topical corticosteroid interruption burst corneal inflammation and induced stromal necrosis in the other patient. These intractable mycobacterial infections were finally controlled with penetrating keratoplasty. Our data suggest that a rapidly growing mycobacteria culture is required when clinical presentation consists of chronic bacterial keratitis or infectious crystalline keratopathy.