Mycobacterium chelonae Keratitis

Abstract

To describe the microbiologic diagnosis of putative Mycobacterium chelonae keratitis in a soft contact lens wearer by initial evaluation of Gram- and Kinyoun (acid fast)-stained smears of fluid from patient's contact lens care system. Corneal ulcer of suspected Acanthamoeba etiology developed in a 28-year-old soft contact lens wearer. After corneal scrapings were negative, microbiologic consultation led to evaluation of stained smears and culture of fluid from patient's contact lens care system. Gram stain of smears showed a polymicrobic flora distinguished by numerous gram-positive, beaded, tightly banded, "diphtheroid-like" bacilli strongly suggestive of a rapidly growing mycobacterial species. Kinyoun-stained smears revealed innumerable acid-fast bacilli singly and in tightly woven bundles (cords), which culturally proved to be M. chelonae. Treatment with ciprofloxacin and amikacin resolved the ulcer. Diagnosis of M. chelonae keratitis in contact lens wearers is often delayed or even overlooked. Additionally, in the absence of overt corneal injury, eg, trauma or surgery, a source for the infecting mycobacterial species in the setting of contact lens wear has not been identified. If searched for, however, as in the present case, the patient's contact lens care system may serve as the reservoir for the microorganism. Staining for acid-fast bacilli is further recommended when smears of contact lens care solution of a patient with a corneal ulcer shows the presence of gram-positive "diphtheroid-like" organisms.